07-Jul-19 12:54 AM Everything about detecting, quantifying and producing all sorts of (mostly ionizing) radiation! 07-Jul-19 12:54 AM Pinned a message. 07-Jul-19 11:03 AM I use my trusty Ludlum Model 3 with pancake detector it see if tungsten wire is thoriated or not. I also use it to demonstrate how alpha particles can be blocked by just about anything using canary glass as the source. Good safe demonstration for The uninitiated. 07-Jul-19 03:18 PM I use my ludlum 3 mostly with the pancake or scintillator, both having the advantage of seeing low energy photons, which are the biggest part of the spectrum in most medium high voltage systems 07-Jul-19 03:18 PM I wrote something about russian neutron detectors a while ago https://gigabecquerel.wordpress.com/2019/05/22/collection-of-information-about-russian-snm-tubes/ 07-Jul-19 03:18 PM if I find the time I could to a presentation of the most common radiation detectors, what they detect, how to use them etc 07-Jul-19 03:39 PM Now this is a channel I can get behind 07-Jul-19 03:44 PM I knew it 07-Jul-19 03:44 PM if you want to get behind something, try shielding 07-Jul-19 03:48 PM But that takes away the risk factor D: 07-Jul-19 03:48 PM you can always be hit by falling lead 07-Jul-19 03:49 PM Where am I supposed to get that thrill of possibly giving myself cancer in 20+ years from then? 07-Jul-19 03:49 PM Though if I really want to do that I'm gonna need a bigger tube 07-Jul-19 03:50 PM you could try smoking 07-Jul-19 03:50 PM I think lung cancer is way worse than skin cancer 07-Jul-19 03:51 PM The asthma it'd revive would be worse than all of it combined 07-Jul-19 03:51 PM I got a reminder of the hell that was my childhood the other month when I got bronchitis 07-Jul-19 03:52 PM oof 07-Jul-19 08:47 PM Anyone happen to know if the soviet SI-19N tubes that were available a few years ago are B10 lined corona tubes or He3 filled corona tubes? Was pretty sure it was the boron when I bought it but now there seem to be people claiming they are He3... 07-Jul-19 08:47 PM Probably doesn't make a huge difference for using one I suppose 08-Jul-19 12:02 AM they're He3 08-Jul-19 12:02 AM https://consensus-group.ru/radiation-counters/neutron-counters/corona-counters/209-snk-30200-46om 08-Jul-19 12:02 AM and it does make a huge difference! 08-Jul-19 12:08 AM Interesting...was a pretty big score for $50 then 08-Jul-19 12:08 AM yep, not bad 08-Jul-19 12:08 AM http://physicsopenlab.org/2017/01/30/neutron-detector/ I had seen this when looking into driving it which says that it is B10 lined 08-Jul-19 12:08 AM I only got my smallest HE3 tube for 50 08-Jul-19 12:08 AM there's a lot of bullsh wrong information floating around bout the SNM tubes 08-Jul-19 12:08 AM most of which comes from higgins paper 08-Jul-19 12:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190708_090914-154BB.jpg 08-Jul-19 12:08 AM (isn't it cute? ❤ ) 08-Jul-19 12:10 AM So basically trust the datasheet for the SNK-30 as a reference more than those guys haha 08-Jul-19 12:11 AM Yep 08-Jul-19 12:11 AM biasing is easy af, over a huge range of hundreds of volts 08-Jul-19 12:11 AM 47Mohm resistor for bias, and decoupling into 100 p / 16 k 08-Jul-19 12:11 AM it's all described in detail in the link above, the one with the friendly yellow bucket 08-Jul-19 12:13 AM That is a cute little tube! Probably would be easier to set up a moderator for than mine will be 08-Jul-19 12:14 AM of I've got moderators for all of my tubes 08-Jul-19 12:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190707_170839974-498A8.jpg 08-Jul-19 12:15 AM just buy some PVC from the hardwarestore and do some casting with paraffine 08-Jul-19 12:15 AM well if you want to go there 08-Jul-19 12:15 AM one sec 08-Jul-19 12:15 AM Considering that or just buying some HDPE sheet and cutting it up 08-Jul-19 12:15 AM It was way bigger than I expected it to be when I ordered it heh 08-Jul-19 12:15 AM Was buying some pancake geiger counter tubes and decided why not 08-Jul-19 12:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190708_091641-AAD1E.jpg 08-Jul-19 12:17 AM Mine's bigger :P 08-Jul-19 12:18 AM Very nice! 08-Jul-19 12:18 AM hehe 08-Jul-19 12:18 AM the only thing I'm unsure about is the Si-10n 08-Jul-19 12:18 AM but I assume it's He3 08-Jul-19 12:18 AM I've got all the operating data here, but no info about whether it's B10 or He3 08-Jul-19 12:18 AM but it'd proportional, so either BF3 or He3 08-Jul-19 12:18 AM and iirc the BF3 ones were called SNMO 08-Jul-19 12:21 AM I feel like I remember there being a couple great websites with info about the soviet surplus tubes when I bought this stuff in 2017 but I cant seem to find them anymore 08-Jul-19 12:22 AM there are many 08-Jul-19 12:22 AM but there's no information about the SI-10n 08-Jul-19 12:22 AM just like the SNM50 (the tiny tube above) 08-Jul-19 12:23 AM Ah, place I remember had the original russian datasheets all scanned but no dice 08-Jul-19 12:23 AM Google translate works wonders on photos and made it easy to figure out the info 08-Jul-19 12:24 AM that's what I've done over the last couple years 08-Jul-19 12:24 AM eg. there's this http://www.quartz1.com/price/techdata/Priemniki_i_detektory_izluchenij_2012.pdf 08-Jul-19 12:24 AM which mentions all the operating data, but not the magic ingredient 08-Jul-19 12:25 AM What an oversight 08-Jul-19 12:25 AM Have you considered emailing/messaging one of the sellers asking for photos of a broken tube? 08-Jul-19 12:27 AM ...I just ordered two 08-Jul-19 12:27 AM it's proportional, and via the pulse height spectrum it gives you can determine the pressure, fill gas and whatnot 08-Jul-19 12:28 AM Hopefully you don't find out the magic ingredient through negative postal experiences. 08-Jul-19 12:28 AM nah, I know that seller, he'S great 08-Jul-19 12:29 AM Didn't mean to imply the seller wasn't...just the postal services 08-Jul-19 12:29 AM he's also great at packaging safely 08-Jul-19 12:29 AM funny thing is I've never had something broken from the ukraine, but lot's of things in national shipping 08-Jul-19 12:32 AM Interesting. I had one box of geiger counter tubes from ukraine go missing somewhere between arriving in the USA and getting to customs...was super weird. Had to pay postage for the replacements and added in the SI19N to the order. Everything worked out perfect in the end 08-Jul-19 12:32 AM Still wonder what ever happened to the first box and who ended up with some nice soviet pancake tubes 08-Jul-19 12:32 AM USPS is hit and miss for shipping damage...more likely to lose things entirely! 08-Jul-19 12:33 AM feels like customs like "loosing" stuff 08-Jul-19 12:33 AM I've sent a package to someone from this server and at first the whole package was missing according to tracking, after they found it it was delivered but still missing two things 08-Jul-19 12:33 AM which are still missing to this day 08-Jul-19 12:35 AM Very odd 08-Jul-19 12:35 AM Are you just interested in neutron counters or have you played with any of the soviet pancake geigers? I was pretty impressed by the sensitivity of the SBT-10A tubes. The SBT-11A tubes I picked up could have been better but they are a cute little alpha tube with a huge window 08-Jul-19 12:38 AM I've played with pretty much every kind of detector out there 08-Jul-19 12:38 AM my main issue with most russian window geiger tubes is the lack of any light shielding 08-Jul-19 12:38 AM 90% of those tubes tick when hit by a 405 nm laser 08-Jul-19 12:41 AM Havent tried that but i am sure that is probably an issue with them. I usually leave the aluminum cover on the big one I have 08-Jul-19 12:47 AM tbh I'm a bigger fan of scintillators than GM or even prop 08-Jul-19 12:48 AM My only real experience with scintillators was brief joy and perfect spectra and then lots of frustration haha 08-Jul-19 12:48 AM Should revisit that someday but too many other projects that do not really need it 08-Jul-19 12:49 AM ...yet 08-Jul-19 12:50 AM Haha I suppose 08-Jul-19 12:50 AM Need to get a new oscilloscope to really debug that since I lost mine (loaned tools are great till they need to go home!) 08-Jul-19 12:52 AM oof, that sucks 08-Jul-19 12:52 AM I really like the TDS754D I have 08-Jul-19 12:52 AM but it really isn't for everyone 08-Jul-19 12:57 AM That is a much nicer scope than I should probably even be looking at 08-Jul-19 12:59 AM ah well 08-Jul-19 12:59 AM after that my all time favourite is the 1054z 08-Jul-19 01:00 AM I was looking at those or the Siglent SDS1104X-E 08-Jul-19 01:00 AM Cannot justify buying one at all right now but maybe if I get some more consistent machining work lined up 08-Jul-19 01:01 AM hmm, I don't really like siglent 08-Jul-19 01:01 AM but after the last few scopes I can't really argue against them with facts 08-Jul-19 01:01 AM Definitely open to input on nonfactual reasons to reconsider 08-Jul-19 01:01 AM Sometimes that can prove to be pretty important 08-Jul-19 01:02 AM well their first stuff just flat out rusted when it arrived 08-Jul-19 01:03 AM That isnt a great sign 08-Jul-19 01:03 AM Not a huge concern (I am in sunny Southern California) for me but raises build quality questions. 08-Jul-19 01:04 AM yep 08-Jul-19 01:04 AM I liked the 1054z's user interface a little bit more but I only have about 2mins of navigating around the menus of each as experience 08-Jul-19 01:04 AM The specs of the siglent for the price (and ability to hack the upgrades) make it tempting though 08-Jul-19 01:05 AM the rigol can be hacked as well 08-Jul-19 01:05 AM but only up to 100 MHz etc 08-Jul-19 01:05 AM what do you usually do? That should decide what scope you get 08-Jul-19 01:10 AM I am a bit all over the place, I probably do not do anything that would likely need more than the 50MHz the 1054z offers. 08-Jul-19 01:10 AM Couple projects that need the scope would be debugging the scintillator to figure out where exactly things are going awry (PMT, preamp, etc) 08-Jul-19 01:10 AM And working with the si19n tube to make sure everything is working right 08-Jul-19 01:10 AM Then a couple similar projects using SiPIN detectors 08-Jul-19 01:10 AM Sorta learning as I go for some of this stuff 08-Jul-19 01:13 AM that sounds a lot like you'd need great single shot performance 08-Jul-19 01:13 AM => high sampling rate and deep memory 08-Jul-19 01:15 AM My lack of first hand experience with this stuff makes it hard for me to really know what baselines to really aim for in the specs 08-Jul-19 01:15 AM Cant remember the model of scope I was using in the past but it was some ancient CRT display unit that was having trouble keeping up and zero data logging 08-Jul-19 01:16 AM some of the devices you've mentioned are really fast, so 100+ MHz would be great 08-Jul-19 01:16 AM Not a whole lot of comparison 08-Jul-19 01:16 AM and 1+ Gs/s, but that's a given nowadays 08-Jul-19 01:19 AM Guess this will be another thing that stretches my budget once I decide I can really justify it to myself. Are you familiar with any of the other options that would be comparable to the 1104x-e? It seemed like the best value for the feature set it offered but you know a lot more about this subject than I do 08-Jul-19 01:20 AM well the 1054z has the same sampling rate and bandwidth, but higher memory and a smaller screen 08-Jul-19 01:20 AM BUT the rigol doesn't have siglents SPO thingy, which is a great feature 08-Jul-19 01:20 AM which I'd prefer, even over the deeper memory 08-Jul-19 01:28 AM on the bandwidth...isnt the 1054z 50MHz (hackable to 100 and cheaper ~$350) and the 1104x-e 100MHz (hackable to 200 and ~$500)? 08-Jul-19 01:29 AM yep 08-Jul-19 01:29 AM higher bandwidth is better 08-Jul-19 01:29 AM atm it all points towards the siglent 08-Jul-19 01:30 AM Just wanted to make sure I had not missed something when you said the 1054z has the same sampling rate and bandwidth 08-Jul-19 01:32 AM Wasn't 100% sure about the Hackability of the siglent ^^ 08-Jul-19 01:33 AM Ahh, seemed pretty well figured out when I was looking into scopes last (few months ago) - hope that hasnt changed 08-Jul-19 01:35 AM maybe go to an Electronics store that has both ahd try them 08-Jul-19 02:00 AM Totally unrelated to the earlier subject...super interesting video: https://www.youtube.com/watch?v=ssH9o32CZtg 08-Jul-19 02:00 AM Cannot even imagine their reaction when they were told "You need to set these plutonium buttons on fire...for science" 08-Jul-19 02:03 AM I'd start thinking veeeery hard if that really is the workplace for me 08-Jul-19 02:03 AM that video is scary 09-Jul-19 03:50 AM Considering the test conductors are handling the leftovers from a nuclear weapons programme, It'd be a pretty late opportunity for that realisation… 09-Jul-19 07:37 AM My brother works at Hanford. That place is pretty messed up. 09-Jul-19 09:59 AM ohh, cool! 09-Jul-19 09:59 AM any shareable pics? 09-Jul-19 01:00 PM got a cute little Am source today 09-Jul-19 01:00 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190709_215851-68D89.jpg 09-Jul-19 01:00 PM now, let's measure it's activity! 09-Jul-19 01:00 PM (SMA for scale) 09-Jul-19 01:00 PM looks like a slightly oversized smoke detector source 09-Jul-19 01:00 PM I have a few of them in my cookie jar 09-Jul-19 01:00 PM Which I should probably post here since it's relevant 09-Jul-19 01:02 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190709_220158-EE5AC.jpg 09-Jul-19 01:02 PM trusty old ludlum 3 and a tungsten shielded pancake 09-Jul-19 01:02 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190709_220511-0AD87.jpg 09-Jul-19 01:02 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190709_220516-7E89C.jpg 09-Jul-19 01:02 PM 290 kcpm 09-Jul-19 01:02 PM but how much is that in activity? 09-Jul-19 01:02 PM first, let's convert it to cps, that's easy 09-Jul-19 01:02 PM 4833 counts per second 09-Jul-19 01:02 PM now let's look for the efficiency 09-Jul-19 01:02 PM I don't have a datasheet for that exact probe, but I know it has the same tube as the ludlum 44-9 09-Jul-19 01:02 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B236B.png 09-Jul-19 01:02 PM There's no Am-241 in that list, but Pu293 comes pretty close, as they are both high energy alpha emitters with only slight gamma emission 09-Jul-19 01:02 PM so I'm gonna assume 15% over 4pi, meaning that 15% of all decays in my sample result in one detection 09-Jul-19 01:02 PM so that would be 32220 decays per second, or 32.22 kBq 09-Jul-19 01:02 PM The source is rated at 33.3 kBq, with an unknown tolerance 09-Jul-19 01:02 PM not too bad for a simple geiger counter with an uncalibrated detector! 09-Jul-19 01:11 PM how manu uCi is that? 09-Jul-19 01:12 PM 0.9 09-Jul-19 01:12 PM so standard detector source 09-Jul-19 01:12 PM last I checked standard was 1uCi 09-Jul-19 01:13 PM How many gBq though 09-Jul-19 01:13 PM @Treehouseman depends on where you are, model and whatnot 09-Jul-19 01:13 PM :/ looks like I don't have any pictures on my phone of my cookie jar 09-Jul-19 01:13 PM @AdamMcCombs that would be 0.000322 Gigasquirrels 09-Jul-19 01:14 PM I have a lead glass cookie jar I found at a thrift store I use as my lead pig 09-Jul-19 01:14 PM I have a lead pig I use as my lead pig 09-Jul-19 01:15 PM I don't have money for that, or the sources to require it :P 09-Jul-19 01:15 PM just a watch with some radium dots, crappy uranium glass, and a handful of smoke detetor sources 09-Jul-19 01:15 PM well, there's the fiestaware platter but that doesn't fit 09-Jul-19 01:15 PM it's also my hottest source lol 09-Jul-19 01:15 PM well, when the xray is off 09-Jul-19 01:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190709_221845-08535.jpg 09-Jul-19 01:19 PM 16 kg and at least 3 cm lead to every side 09-Jul-19 01:19 PM and I have some sources I still can detect from the outside 09-Jul-19 01:19 PM found it at the scrapyard for cheap 09-Jul-19 01:19 PM a backpack with three of those and a 2 km hike back to the train station 09-Jul-19 01:19 PM that was fun 09-Jul-19 01:36 PM :P 09-Jul-19 02:13 PM Nice score though 09-Jul-19 02:13 PM There is an old shooting range out in the mountains near me that I have been meaning to go grab some more lead from 09-Jul-19 02:25 PM good luck with that! 09-Jul-19 02:25 PM too bad they don't shoot spectroscopy lead 09-Jul-19 03:05 PM Hmm, collecting bullets for science???!!! 09-Jul-19 03:05 PM Sounds like a good reason for me to rig up a target that can collect rounds for me as I shoot. 10-Jul-19 01:28 AM http://www.hurriyetdailynews.com/18-grams-of-radioactive-californium-seized-in-bolu-144744 Welll... 10-Jul-19 01:28 AM The most long-lived isotope of Cf is around 60 GBq per gram 10-Jul-19 01:28 AM but that's fairly uncommon, most of the time you'd find Cf 252, which is around 20 TBq per gram 10-Jul-19 01:28 AM http://atom.kaeri.re.kr:8080/cgi-bin/decay?Cf-252%20A 15.7% of the time there's a 43 keV gamma 10-Jul-19 01:28 AM some very coarse maths later 10-Jul-19 01:28 AM 0.5 Sv/h 11-Jul-19 09:46 AM Anyone know what the (I am assuming) source in this listing? Was looking through this guys auctions after giga linked those proportional neutron tubes the other day 11-Jul-19 09:46 AM https://www.ebay.com/itm/113766859411 11-Jul-19 09:47 AM yep, it's a 20-50 kBq Sr/Y 90 source, from a DP-5B geiger 11-Jul-19 09:48 AM Interesting - haven't seen one of those before 11-Jul-19 09:48 AM Suppose not many of those have made their way out of Europe 11-Jul-19 09:48 AM that's it 11-Jul-19 09:48 AM the source itself looks like the pull tab of a can 11-Jul-19 09:48 AM but it's glued to the piece of tube here 11-Jul-19 09:48 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190711_185004-704A6.jpg 11-Jul-19 10:51 AM oof 11-Jul-19 10:51 AM I just got green light for a complete HPGe setup ❤ 11-Jul-19 10:51 AM 1.9 keV at 1.33 MeV :3 11-Jul-19 02:37 PM omg 11-Jul-19 02:37 PM like, for keepsies? :o 11-Jul-19 02:39 PM yep! 11-Jul-19 02:39 PM 40%, 1.9 keV and a nim bin with everything it needs 11-Jul-19 02:40 PM omg nice 11-Jul-19 02:41 PM yes! 11-Jul-19 02:41 PM I'm so f*ing happy 11-Jul-19 02:41 PM but I think the dewar needs to be pumped down again 11-Jul-19 02:41 PM according to them it holds 30 L LN2 for 7-10 day 11-Jul-19 02:41 PM my 18 L dewar has a holding time of... 220 days 11-Jul-19 02:47 PM how much is that setting you back? 11-Jul-19 02:47 PM congrats though! 11-Jul-19 02:50 PM all I have to do is drive 3 hours and get it 11-Jul-19 02:50 PM woah major score 11-Jul-19 02:50 PM thats awesome 11-Jul-19 02:51 PM ohhh yes 11-Jul-19 02:51 PM I visited that lab some months ago, and straight up asked for that detector, since it was replaced with a newer one 11-Jul-19 02:51 PM today I got an email "If you say yes you'll get it, if not this and that university will get it 11-Jul-19 02:51 PM now I just need to get my fusor up and running 11-Jul-19 02:51 PM ...and do some neutron guiding magic 11-Jul-19 02:51 PM a hollow beryllium half sphere would be awesome 11-Jul-19 02:51 PM but on the other hand... 11-Jul-19 03:01 PM i have yet to really wrap my mind around what exactly it is that makes beryllium a neutron 'reflector' 11-Jul-19 03:01 PM that kind of seems like a misnomer because when i think 'neutron reflection' i think niobium supermirrors and ultracold neutrons 11-Jul-19 03:02 PM it's actually quite simple 11-Jul-19 03:02 PM most neutron interactions are just elastic scattering 11-Jul-19 03:02 PM and if a neutron bumps into a particle with many times the neutron mass it will change direction 11-Jul-19 03:02 PM it will go back where it came from, or deflect up to 90° from its original path, depending on the position it hit 11-Jul-19 03:02 PM and beryllium just has a high scattering cross section, but don't ask me why 11-Jul-19 03:02 PM that's why many heavy elements are good neutron reflectors as well, their mass is way higher than the neutrons, so only the condition of high cross section has to be met 11-Jul-19 03:02 PM neutron moderation and most other stuff is just billiards with 10^22 balls per cm³ 11-Jul-19 04:22 PM ah, so it's the scattering cross section that does it, then 11-Jul-19 04:22 PM it's just a very diffuse reflector, not like a total internal reflection thing 11-Jul-19 07:26 PM I'd take a look at neutron optics, some really crazy stuff for manipulating neutron beams. I think it would pretty cool to see someone do some neutron beamline stuff using a fusor as a source 11-Jul-19 11:12 PM 11-Jul-19 11:12 PM i think i have literally everything to just.. build a fusor, make some neutrons, and pull it apart once i'm bored of burning up my tungsten wire 11-Jul-19 11:14 PM @Applied_Ion we look at lobster lensing for nuetrons. I think a geant sim was ran on it at some point with promising results 11-Jul-19 11:14 PM but really i'd like to go the pulsed route for neutron studies, an attempt at a TOF beamline on a DPF is still on the table for me 11-Jul-19 11:14 PM googles lobster lensing 11-Jul-19 11:14 PM oh it's a microchannel thing, neat 11-Jul-19 11:14 PM kinda like a collimator i guess? 11-Jul-19 11:18 PM mx.qualia, same boat here... just need some pressure measuring hardware and to hook everything up 11-Jul-19 11:18 PM Sorta want to try replicating these down the line: https://www.youtube.com/watch?v=fOsoueOIURo 11-Jul-19 11:27 PM they need really high voltage afaict, they're just a beam-on-target widget i think 11-Jul-19 11:31 PM definitely would be basically pointless due to the very very very low neutron output (think they say in the video 200 neutrons...total? ...per second? who knows) 11-Jul-19 11:31 PM just an amusingly small form factor 11-Jul-19 11:34 PM i actually don't know what legitimate use those things could have besides maybe really sensitive low-flux backscatter NAA forsolid-state moisture gauges, or, like, weapons 11-Jul-19 11:34 PM but they are really cute.. 12-Jul-19 12:50 AM 200 neutrons in total would be a bit... disappointing 12-Jul-19 01:46 AM I've got papers on the neutristor lol 12-Jul-19 01:46 AM I'll post them 12-Jul-19 01:46 AM Very low yields, and they require DT targets still to get them 12-Jul-19 01:46 AM Fortunately voltage input is pretty low, they take advantage of large field enhancement to create acceleration potential 12-Jul-19 01:46 AM @qualia @Mason_Yu is building a TOF beamline for his dpf, though for ion energies not neutrons. 12-Jul-19 01:46 AM Collimators shoukd be pretty easy to make, just chunks of different material. At the linac it's usually brass, plastic, lead, steel, etc 12-Jul-19 01:51 AM well, a neutron collimator is somewhat different 12-Jul-19 01:51 AM you can't work with fields, but have to go the scattering or interference route 12-Jul-19 01:51 AM @LRM actually I think pyroelectric crystal neutron generators put out a lot more than the neutristor, and would be easier to make in theory 12-Jul-19 01:51 AM @GigaSquirrel yeah lol but physically just chunks of material in a pipe 12-Jul-19 01:52 AM if you put it like that it's just all material in a pipe 12-Jul-19 01:53 AM True, but haven't seen it done on amateur systems yet 12-Jul-19 01:53 AM because it's hard to get the materials and needed geometry 12-Jul-19 01:54 AM Brass, plastic, and steel as cylinders? 12-Jul-19 01:54 AM You can practically buy the stock as is. 12-Jul-19 01:54 AM Or get water jet cut 12-Jul-19 01:54 AM Maybe harder for European fusioneers if material sourcing is an issue, but no excuse for US folks lol 12-Jul-19 01:54 AM I'll post the neutristor and pyroelectric papers in the resources area. @LRM you may be interested in these if you are looing to explore them lol 12-Jul-19 02:02 AM sourcing brass, steel and whatnot is easy here, but I don't see how that would help in guiding neutrons? 12-Jul-19 02:04 AM depends on geometry. Like you said, its all about scatter. Thats just common material used at the lab for collimators I have seen 12-Jul-19 02:04 AM of course I think they design them in like MCNP 12-Jul-19 02:04 AM huh, I only have 1 paper on the neutristor, thought I had more lol 12-Jul-19 02:05 AM huh, do you have a source for that? 12-Jul-19 02:05 AM I've only ever seen supermirrors for guiding and borated steel or something similar for absorbing everything you don't want 12-Jul-19 02:05 AM I'll dig through my papers, see what I have. Haven't looked much into neutron stuff, but I know for collimators you definitely don't need anything exotic 12-Jul-19 02:06 AM and I'm trying to avoid the latter, as it is per definition very inefficient, which cannot be tolerated, considering the already low yield of a fusor 12-Jul-19 02:06 AM pied piper 12-Jul-19 02:06 AM what are the devices used as an ignitor in thermonuclear weapon systems? 12-Jul-19 02:06 AM i mean in modern bombs 12-Jul-19 02:12 AM @Applied_Ion that paper you posted about neutron optics, that's just absorbing whatever you don't want 12-Jul-19 02:12 AM and considering the fusor as a point source that's far from efficient 12-Jul-19 02:13 AM yeah lol, that's essentially what a lot of it is. Or changing the energy via thermalizing. Sorry, I don't have many papers on the subject. When I get back to work after my parental leave though I can certainly ask more about it 12-Jul-19 02:13 AM you know the linac is a point source too 12-Jul-19 02:13 AM hits a target which radiates a burst of neutrons pretty isotropically, except in massive numbers 12-Jul-19 02:14 AM that's the point 12-Jul-19 02:14 AM some are more directional, but still crap them out everywhere lol 12-Jul-19 02:14 AM what are you looking for? 12-Jul-19 02:14 AM generating many neutrons is easy, so most people don't care about the efficiency of their guiding, since they can always make more neutrons if needed 12-Jul-19 02:14 AM kinda coherent neutron source? ^^ 12-Jul-19 02:14 AM as close to a parallel beam as I can get 12-Jul-19 02:14 AM thermal, that is 12-Jul-19 02:16 AM for that, you essentially block out most the neutrons for everything except a small cross-section down a large flight tube 12-Jul-19 02:16 AM which is very, very inefficient 12-Jul-19 02:16 AM its a dirt inefficient process by nature lol 12-Jul-19 02:16 AM so I'm trying to reflect most of the neutrons going the wrong way 12-Jul-19 02:17 AM hence why a lot of emphasis is placed on high quality detectors 12-Jul-19 02:17 AM lead is good at bouncing neutrons lol 12-Jul-19 02:18 AM yep, that would be my first try 12-Jul-19 02:18 AM we have a massive, massive pile of lead as a large block called the lead slowing down mass spectrometer at the end of one beamline. Essentially, neutrons enter and bounce around a bunch of times and make multiple passes through the detector, increasing S/N 12-Jul-19 02:18 AM what's the best moderator to cool them down? 12-Jul-19 02:18 AM i mean cooling the neutrons in the thermal domain 12-Jul-19 02:19 AM everything with high hydrogen density 12-Jul-19 02:19 AM any good absorber. Water, polyethylene, anything with high hydrogen content 12-Jul-19 02:19 AM beat me to it lol 12-Jul-19 02:19 AM ok, and scattering on beryllium? 12-Jul-19 02:19 AM I think you're mixing absorber and moderator here @Applied_Ion 12-Jul-19 02:20 AM they use poly to thermalize them too 12-Jul-19 02:20 AM well, essentially moderators are also good absorbers lol 12-Jul-19 02:20 AM no, they should not be 12-Jul-19 02:20 AM moderating neutrons is just shifting their spectrum closer to thermal temperatures 12-Jul-19 02:21 AM i mean if they scatter long enough with the beryllium they will get into thermal equilibrium with it, right? 12-Jul-19 02:21 AM and absorbing them is just that, a nuclear reaction for stopping a neutron 12-Jul-19 02:21 AM Yep 12-Jul-19 02:21 AM that's moderation 12-Jul-19 02:22 AM if you thermalize them enough they are eventually stopped though right? 12-Jul-19 02:22 AM no? 12-Jul-19 02:22 AM moderator and absorber are often mixed, as in borated polyethylene, maybe you're getting that mixed up 12-Jul-19 02:24 AM maybe I am mixing them up lol, I think we use moderators more than absorbers. Borated poly and lithiated poly are popular ones, I think we use lithiated more 12-Jul-19 02:24 AM @GigaSquirrel you are the expert in this area lol, I'll leave it to you. I don't really cross into the neutron stuff that much, other than in passing what I see used in experiments or help setting up stuff 12-Jul-19 02:25 AM so hmm, would it be possible to build a source from i dunno UD3 and Be? in the right geometric configuration? 12-Jul-19 02:25 AM with a modulated source on one end 12-Jul-19 02:26 AM @N00N you're describing a nuclear reactor 12-Jul-19 02:26 AM yeah i know, i mean a compact configuration 12-Jul-19 02:26 AM as a thermal neutron source 12-Jul-19 02:26 AM like deskside 12-Jul-19 02:26 AM :3 12-Jul-19 02:27 AM I would advise against that, considering heat and gamma output of a reactor... 12-Jul-19 02:27 AM most thermal neutron sources I "know" are larger facilities 12-Jul-19 02:27 AM ok hmm 12-Jul-19 02:27 AM but it would be a nice thing to have 12-Jul-19 02:28 AM you can do that with a fusor 12-Jul-19 02:28 AM waaaay lower flux but also not instantly dead 12-Jul-19 02:29 AM yeah, fusor as the source for modulation and then the tube reactor in front of it 12-Jul-19 02:29 AM ahh, I see where you're coming from 12-Jul-19 02:29 AM i mean, we could chat over neutrons 12-Jul-19 02:29 AM IP over thermal neutron communication 12-Jul-19 02:30 AM that's actually used in highly sensitive neutron detectors 12-Jul-19 02:30 AM surround them with a subcritical mass of uranium and let the incoming neutrons be multiplied by the U 12-Jul-19 02:30 AM yes kinda that's what i mean 12-Jul-19 02:30 AM Fission chamber? 12-Jul-19 02:31 AM "the neutron link corp" 12-Jul-19 02:31 AM not a fission chamber, but just uranium around sth like a He3 tube 12-Jul-19 02:31 AM Ah, though fission chambers also use uranium right? 12-Jul-19 02:32 AM Yep, but not for multiplication 12-Jul-19 02:32 AM https://inis.iaea.org/collection/NCLCollectionStore/_Public/16/031/16031513.pdf 12-Jul-19 02:33 AM yeo 12-Jul-19 02:33 AM yep 12-Jul-19 02:33 AM oh boy, that neutron stuff is amazing 12-Jul-19 02:37 AM Makes sense, though this stuff is all pretty new to me lol 12-Jul-19 02:37 AM I'll stick to beams and pulses lol 12-Jul-19 02:40 AM let'S work together and build the biggest spallation source 12-Jul-19 02:40 AM ehehe 12-Jul-19 02:40 AM if you have the money, let's go \o/ 12-Jul-19 02:41 AM Biggest amateur or biggest biggest lol 12-Jul-19 02:41 AM i'm on board! %) 12-Jul-19 02:41 AM biggest biggest of course 12-Jul-19 02:41 AM biggest 12-Jul-19 02:41 AM Sounds big lol 12-Jul-19 02:42 AM goal is >10^18 n/s 12-Jul-19 02:43 AM Spallation put out more than reactors? 12-Jul-19 02:43 AM That's a lot lol 12-Jul-19 02:43 AM Like 4 orders magnitude more than our linac 12-Jul-19 02:43 AM I was looking at the european spallation source, which is being build atm 12-Jul-19 02:43 AM but how to fund? 12-Jul-19 02:43 AM neutron-candy? 12-Jul-19 02:43 AM neutron-mate softdrinks? 12-Jul-19 02:44 AM nukacola! 12-Jul-19 02:44 AM wow yeah 12-Jul-19 02:44 AM und nuclear is pure light water 12-Jul-19 02:44 AM nuclear shower gel 12-Jul-19 02:44 AM nuclear TP 12-Jul-19 02:46 AM nuclear everything! 12-Jul-19 02:46 AM and a homecomputer named "the neutron" 12-Jul-19 02:46 AM but nuclear candy would be quite fun 12-Jul-19 02:46 AM m&m style, protons, neutrons etc 12-Jul-19 02:46 AM with quarks inside - if that's not to expensive 12-Jul-19 08:59 AM my TOF beamline idea is basically going to be an in-vacuum scintillator stuck on a small viewport with a pmt on the other side of said viewport in atmosphere; it'll be interesting to see if i can do pulse-shape discrimination and also how far it'll have to be from the focus to be able to pick out fast neutrons and x-rays as separate pulses 12-Jul-19 08:59 AM if i could encase the whole thing minus this beampipe in a big beryllium hemisphere it'd be interesting to see how that smears out whatever amount of the reflected pulse makes it back 12-Jul-19 09:02 AM Quick note probably a good idea to not use optical oil for coupling. It does improve optical performance but even vacuum compatible oil will deposit on unwanted surfaces on the scintillator. A bigger concern with phosphor for sure but will quickly affect low energy x Ray performance 12-Jul-19 09:03 AM fair; was going to go looking for a low-volatility optical adhesive and make it a permanent fixture 12-Jul-19 09:06 AM There might be something good out there in the LIGO vacuum handbook. Any optical compound on scintillators in vacuum has literally cost me hundreds and clients thousands of dollars in new scintillators. 12-Jul-19 09:08 AM >.>` 12-Jul-19 09:08 AM welp 12-Jul-19 09:08 AM clearly i should pop the glass out of a viewport and just remount the scintillator in place on an o-ring or however that's done 12-Jul-19 09:10 AM It's just been contamination because it's so close together. Optical loss is only a few percent if I recall. Thinking about it though ligo does a massive amount of optics stuff so they probably know the right solution that wouldn't cause a problem 12-Jul-19 09:10 AM I think I wrong on optical loss so correct me if so 12-Jul-19 09:10 AM This is what ligo uses Optocast 3553LV-UTF-HM 12-Jul-19 09:15 AM use vacuum grease for coupling 12-Jul-19 09:15 AM it's thick enough to hold a small scintillator 12-Jul-19 09:15 AM What makes there vacuum compatible materials list so nice is it's written from the perspective of not contaminating optics 12-Jul-19 09:15 AM Vacuum grease to causes problems 12-Jul-19 09:16 AM huh? 12-Jul-19 09:16 AM Yeah 12-Jul-19 09:16 AM Found out the hard way 12-Jul-19 09:16 AM The local outgassing causes contamination that changes the surface properties of the scintillator. Il see if I can find the guide 12-Jul-19 09:19 AM oh 12-Jul-19 09:19 AM If non hydrocarbon oil is ok you can get away with more 12-Jul-19 09:19 AM I only used it with hermetic scintillators so far 12-Jul-19 09:20 AM But you don't want to use silicone oil or more than absolutely necessary ptfe on systems with charged anything 12-Jul-19 09:20 AM Silicone oil results in contamination that's almost impossible to clean off and ptfe once broken down forms hydrofluoric acid on the surface of stuff heavily degrading it over time 12-Jul-19 09:44 AM Also this is all best case no compromise of course... I'm just touchy after wrecking my scintillators... 16-Jul-19 11:26 AM anyone know the max. output current of a ludlum ratemeter? 16-Jul-19 11:26 AM because 16-Jul-19 11:26 AM https://vid.pr0gramm.com/2019/07/12/1d0daabd24dbea11.mp4 16-Jul-19 11:26 AM I wonder how big the cap in there can be if you still want reasonable reprate and power it off a ludlum 16-Jul-19 12:13 PM it's very strongly current limited, i've zapped myself off my ludlum 3 once or twice and it was extremely mild 16-Jul-19 12:13 PM conversely, i wonder how much current a bug zapper puts out.. 16-Jul-19 12:19 PM time to get one and measure it 16-Jul-19 12:19 PM too bad stores here are already closed down 16-Jul-19 12:21 PM :D 16-Jul-19 12:21 PM i have an old bug zapper somewhere, if i ever feel up to cleaning and gutting it i kinda want to try something ridiculous with the 1mA spellman 16-Jul-19 12:21 PM tune the voltage to just below where it flashes over.. 16-Jul-19 12:22 PM alpha spark detector! 16-Jul-19 12:22 PM https://www.youtube.com/watch?v=-8GlzUjYazs 16-Jul-19 12:22 PM oh yeah those things 16-Jul-19 12:25 PM make it big enough and you've got a spark chamber 16-Jul-19 12:25 PM a big one, made of hundreds of bug zappers 16-Jul-19 12:37 PM @GigaSquirrel does your CSA do any pulse shaping? 16-Jul-19 12:39 PM it basically does this 16-Jul-19 12:39 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1029E.png 16-Jul-19 12:40 PM https://gigabecquerel.wordpress.com/2019/05/22/diy-charge-sensitive-amplifier/ some of the image links are busted for some reason 16-Jul-19 12:40 PM i think because maybe fusor.net doesn't allow embeds? 16-Jul-19 12:40 PM ahhh right they changed that 16-Jul-19 12:40 PM thanks for the info! 16-Jul-19 12:40 PM it outputs a somewhat gaussian pulse with 50µs FWHM 16-Jul-19 12:42 PM ah ok, so it does widen it 16-Jul-19 12:42 PM i talked with a friend a bit ago about sound card shenanigans wrt: MCAs and he recommended i go looking for a particular model of thing that happens to be DC coupled 16-Jul-19 12:42 PM and thus gets used a whole bunch for eurorack stuff to get constant voltage inputs/outputs 16-Jul-19 12:42 PM so that way i could do my own uncoupling and factor out an additional potential time constant issue 16-Jul-19 12:45 PM the time constant in mine comes from a simple CR(RC)² filter 16-Jul-19 12:45 PM can be changed to whatever you like 16-Jul-19 12:45 PM do you know the input impedance of a soundcard? 16-Jul-19 12:45 PM if your AC coupling cap and the input impedance form a time constant that's way higher than the signal coming through it can be ignored alltogether 16-Jul-19 12:45 PM if your soundcard has 600 ohm and you use a 10 µF capacitor it has a constant of 6 ms and can be completely ignored 16-Jul-19 12:52 PM looks like 27kohm on the crappier soudncard and 10kohm on the nicer one i haven't gotten around to testing yet 16-Jul-19 12:52 PM really feel like i ought to hook up a pulser to these soundcards and spend some quality time in audacity 16-Jul-19 01:05 PM Are the pics working now? 16-Jul-19 01:15 PM https://gigabecquerel.files.wordpress.com/2019/07/ds1z_quickprint4.png?w=723 -- this 404s 16-Jul-19 01:24 PM what the hell 16-Jul-19 01:24 PM but thanks 16-Jul-19 01:31 PM now it should work 16-Jul-19 01:31 PM maybe 16-Jul-19 01:31 PM perhaps? 16-Jul-19 01:37 PM yeah there it goes :D 16-Jul-19 01:37 PM ty! 16-Jul-19 01:37 PM https://giphy.com/gifs/fury-kung-hackerman-QbumCX9HFFDQA 16-Jul-19 01:37 PM for some reason it didn't like the PNG, so I turned it into a JPEG 16-Jul-19 01:37 PM but don't focus too much on that CSA, as the new revision is already on it's way 16-Jul-19 01:37 PM which should work better, lower noise and such 16-Jul-19 01:37 PM but the only thing changed is the frontend, the pulse shaping etc is still the same 16-Jul-19 03:49 PM I found the Gaussian shaping amplifiers from Cremat work very well for use with charge sensitive preamplifiers 16-Jul-19 03:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Cremat_Pulse_Shaping_Amplifier-C3A84.pdf 16-Jul-19 03:49 PM They are $55 from Amazon, I've been using the 500 ns FWHM version with a PIN diode and a home-made preamp for x-ray detection 16-Jul-19 04:02 PM They do help a lot with noise if your preamplifier tend to pick up high frequency signals. And at lower count rates, you can directly feed the output into an MCA (theremino with an external USB sound card in my case). 16-Jul-19 05:19 PM https://gigabecquerel.wordpress.com/2019/05/22/collection-of-information-about-russian-snm-tubes/ not to be that person, @GigaSquirrel , but there's busted images here too :D 16-Jul-19 05:19 PM probably in other bolg potsts too 17-Jul-19 12:39 AM @qualia no, please be that of person, I would not have found the errors otherwhise 17-Jul-19 01:01 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190717_094512-ED352.jpg 17-Jul-19 01:01 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190717_094621-ECD2B.jpg 17-Jul-19 01:01 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190717_095252-4E18B.jpg 17-Jul-19 01:01 AM got those СИ-10Н today 17-Jul-19 01:01 AM most surprising thing is that the glass seal survived shipping 17-Jul-19 01:01 AM only thing I know is that is is proportional and some voltages 17-Jul-19 01:01 AM no idea if He based, Boron based or what now 17-Jul-19 01:01 AM and I don't know, something about those just screams prototype... 17-Jul-19 01:50 AM ok, pics on the website should work now 17-Jul-19 08:30 AM oh wow, that's scary 17-Jul-19 08:30 AM those cheap electric fly swatters 17-Jul-19 08:30 AM open circuit voltage is 1.65 kV and short circuit current is 7.4 mA! 17-Jul-19 08:30 AM milliamperes! 17-Jul-19 08:30 AM so there's the option of adding a cascade... 17-Jul-19 10:47 AM been there, done that 17-Jul-19 10:47 AM there are different versions of the circuit. some already have a multiplier, some don't 17-Jul-19 10:47 AM in my experience you need to somewhat match the multiplier stages, just any random values might not work 17-Jul-19 11:00 AM match to what? 17-Jul-19 11:01 AM the transformer 17-Jul-19 11:02 AM in what way? 17-Jul-19 11:02 AM impedance matching 17-Jul-19 11:02 AM somehow it needs resonance or something. 17-Jul-19 11:03 AM well mine doesn't 17-Jul-19 11:03 AM transformer => diode => capacitor 17-Jul-19 11:04 AM oh, the simpler version 17-Jul-19 11:05 AM simplest possible 17-Jul-19 02:24 PM Youtube is just full of interesting videos...plutonium burning and now someone eating uranium... https://youtu.be/ejCQrOTE-XA?t=4023 17-Jul-19 02:24 PM Not sure I would trust most of what this guy has to say 17-Jul-19 02:24 PM Done any tests with the new neutron tubes, @GigaSquirrel? curious to see what sort of sensitivity you get out of those СИ-10Н 17-Jul-19 02:26 PM nothing yet, sorry ^^ 17-Jul-19 02:26 PM will take some time, I'm currently in the exams phase and will be at a maker event all weekend next week 17-Jul-19 02:26 PM + my new CSAs haven't arrived yet 17-Jul-19 02:26 PM BUT 17-Jul-19 02:26 PM I am currently printing a case for them, that also acts as a holder for (as a first test) my SNM-18 and 18-1 17-Jul-19 02:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-34856.png 17-Jul-19 02:31 PM Looking good 17-Jul-19 02:31 PM Waiting on your results before I consider ordering one of СИ-10Н tubes heh not that I really need one anyway 17-Jul-19 02:35 PM beware, as if they are He3 I will order every single on of them 17-Jul-19 02:35 PM oh and they will need a special version of my CSA, since 3 kV is it's upper limit and they want 2.95 kV... 17-Jul-19 02:35 PM just different caps and some more cleaning 17-Jul-19 02:40 PM hah well you could probably put them to better use than I will 17-Jul-19 02:40 PM maybe I will just toss out a super low offer and see if the seller will bite 17-Jul-19 02:41 PM seller accepted my $40 offer 17-Jul-19 04:55 PM @GigaSquirrel Just heard this from the seller "Its 99% B10 than He-3" with a counter of $50 18-Jul-19 01:37 AM Hmm, I assumed that, there's no way the piece of glass can hold a couple bar of helium 18-Jul-19 01:37 AM BUT I have no definite answer yet, and until that point I'll just tell myself there's a chance it's He 18-Jul-19 01:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_103253-C0EBE.jpg 18-Jul-19 01:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_103343-B027B.jpg 18-Jul-19 01:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_103413-7415A.jpg 18-Jul-19 02:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_111650-5FD40.jpg 18-Jul-19 02:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_111659-7FE9E.jpg 18-Jul-19 02:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_114424-BDA93.jpg 18-Jul-19 03:29 AM https://www.youtube.com/watch?v=ejCQrOTE-XA&feature=youtu.be&t=4404 18-Jul-19 05:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_141908-D9B77.jpg 18-Jul-19 05:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_141710-3B765.jpg 18-Jul-19 06:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190718_150549-95F9A.jpg 18-Jul-19 09:22 AM Looking good! You electroformed copper on top of it is what was going on in the last few photos, right? 18-Jul-19 09:34 AM Yep! 18-Jul-19 09:37 AM Had any trouble with it flaking off? 18-Jul-19 09:43 AM No, thanks to some Special ingrediant it sticks perfectly! 18-Jul-19 02:12 PM oooo 18-Jul-19 02:13 PM oooo yes 19-Jul-19 08:00 AM Is that copper head gasket spray? 19-Jul-19 08:13 AM Nope! Look at my link in #show-and-tell , it's all explained there 19-Jul-19 12:02 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190719_205615-BDA09.jpg 19-Jul-19 12:02 PM whoop whoop the connectors didn't fit xD 19-Jul-19 12:10 PM lol 19-Jul-19 12:12 PM so let's recoat this thing again 19-Jul-19 12:12 PM once it's done 19-Jul-19 12:12 PM 30 min left to go 26-Jul-19 01:27 AM https://www.youtube.com/watch?v=P99C051arMo 26-Jul-19 01:27 AM Just started watching this but it seems very promising to be full of interesting shots of the facility 26-Jul-19 02:21 AM the professor!!! 05-Aug-19 03:27 PM hi @GigaSquirrel 05-Aug-19 03:27 PM what do you want to know? 05-Aug-19 03:28 PM Hello! 05-Aug-19 03:28 PM http://www.quartz1.com/price/techdata/Priemniki_i_detektory_izluchenij_2012.pdf I have this PDF, but it does not state what neutron detector is what active medium 05-Aug-19 03:28 PM B, BF3, He3 or whatever 05-Aug-19 03:28 PM Yeah it just doesn't 05-Aug-19 03:28 PM Tell me which detector in particular 05-Aug-19 03:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190806_002934-F07CA.jpg 05-Aug-19 03:30 PM SI10N? SN10N? SN10I? 05-Aug-19 03:30 PM SN10N 05-Aug-19 03:30 PM looks to be one-off 05-Aug-19 03:30 PM I have two 05-Aug-19 03:30 PM there's a СИ-10Н in the pdf 05-Aug-19 03:31 PM probably labelled by someone who didn't speak the language then :P 05-Aug-19 03:32 PM SI - impulse counter SN - neutron counter SNM - slow neutron counter SNMO - boron-based slow neutron counter 05-Aug-19 03:32 PM Yours is proportional 05-Aug-19 03:32 PM hmmm, I have different information 05-Aug-19 03:32 PM SNMO is BF3 proportional, but SNM can be corona, boron lined 05-Aug-19 03:33 PM No info on the actual gas, but given it's proportional I'm going to guess it's a weird mix of helium-something. 05-Aug-19 03:33 PM He or BF3 05-Aug-19 03:33 PM and SI, what impulses does it count? 05-Aug-19 03:33 PM SNM is счётчик нейтронов медленных(schotchik neytronov medlennyh), which is literal for "counter neutron slow" 05-Aug-19 03:33 PM SI is just a counting tube 05-Aug-19 03:34 PM but counting what? regular GM, neutron counter, etc? 05-Aug-19 03:34 PM GM 05-Aug-19 03:34 PM But I think sensitive to neutrons 05-Aug-19 03:34 PM slightly 05-Aug-19 03:34 PM https://consensus-group.ru/radiation-counters/neutron-counters There are some pure He SI counters, both corona and proportional 05-Aug-19 03:35 PM Consensus took over most of the designs 05-Aug-19 03:35 PM And improved them considerably 05-Aug-19 03:35 PM They're the company that still makes old Soviet tubes but in a new format 05-Aug-19 03:36 PM yep 05-Aug-19 03:36 PM how do you know my tube is proportional? 05-Aug-19 03:37 PM Found it mentioned somewhere 05-Aug-19 03:37 PM That's basically how you do research on anything Soviet 05-Aug-19 03:37 PM Ruffle through google results for random snippets of text 05-Aug-19 03:38 PM the ebay offering sold it as proportional, and as SI-10N 05-Aug-19 03:38 PM И and Н is easy to confuse 05-Aug-19 03:38 PM and sellers tend to be clueless 05-Aug-19 03:39 PM but the product photos have names printed on them, where it's very obviously a И 05-Aug-19 03:39 PM https://www.ebay.com/itm/113695765135 05-Aug-19 03:39 PM It could be some custom run from a million years ago 05-Aug-19 03:39 PM it certainly feels like it 05-Aug-19 03:39 PM Very few products were standard back then 05-Aug-19 03:40 PM as the tubes have datecodes of 87 and still look like new 05-Aug-19 03:40 PM Because they're often new old stock 05-Aug-19 03:40 PM and the anode contact is just a glass stem, none of the plastic / ptfe caps like on the others 05-Aug-19 03:40 PM They're all glass inside 05-Aug-19 03:41 PM but usually with some mechanical protection 05-Aug-19 03:42 PM Yep 05-Aug-19 03:42 PM Usually some sort of ceramic cement 05-Aug-19 03:42 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190806_004120-A0C3B.jpg 05-Aug-19 03:42 PM Same inside for SBM-20 and whatnot 05-Aug-19 03:42 PM Just cemented in 05-Aug-19 03:43 PM I know, I'm just saying that this adds to the feeling of them being a prototype or whatever 05-Aug-19 03:44 PM Earlier versions look more like prototypes 05-Aug-19 03:44 PM hmm 05-Aug-19 03:44 PM so no information on the fill gas 05-Aug-19 03:44 PM guess I need to measure it myself 05-Aug-19 05:36 PM got a handy mass spec? :P 05-Aug-19 11:25 PM no, but I know how to read detection spectra :P 07-Aug-19 08:40 AM https://carlwillis.files.wordpress.com/2011/10/p1030360_gs.jpg 07-Aug-19 08:40 AM only a tiny bit scary 07-Aug-19 09:11 AM Tube looks odd 07-Aug-19 09:16 AM very 07-Aug-19 09:16 AM https://carlwillis.files.wordpress.com/2011/10/p1030365_gs.jpg 07-Aug-19 09:16 AM Oh, not that odd 07-Aug-19 09:16 AM maybe an early microfocus? 07-Aug-19 09:16 AM Definitely microfocus, the weird tubular wehnelty channel identifies that 07-Aug-19 09:16 AM Looks like my soviet BS series microfocus tubes, except mine have a straight through transmission anode 07-Aug-19 09:16 AM Whereas this one seems to be a target directional one 07-Aug-19 09:17 AM BS series 07-Aug-19 09:17 AM Screws in like a light bulb :D 07-Aug-19 09:17 AM "Honey will you change the x-ray tube in the toilet" 07-Aug-19 09:18 AM "Honey, why is there a x-ray tube in the bathroom?" Well you did not specify visible light! Plus, it's antimicrobial! 07-Aug-19 09:18 AM https://carlwillis.wordpress.com/2011/10/30/trick-or-treat/ Got the pics from here 07-Aug-19 09:18 AM Here's a BS6 07-Aug-19 09:18 AM https://i.spirit.re/MXvKP.JPG https://i.spirit.re/PxUbQ.JPG https://i.spirit.re/8KmaA.JPG 07-Aug-19 09:18 AM The window is thinner than 4 microns 07-Aug-19 09:18 AM I believe 2 07-Aug-19 09:19 AM and that thing sticking out is the anode? 07-Aug-19 09:19 AM Still tight and emits over 25 years later! 07-Aug-19 09:19 AM Yeah 07-Aug-19 09:19 AM -100kV, 40 micron focus 07-Aug-19 09:19 AM And a whopping 2 watts of output 07-Aug-19 09:19 AM Not x-ray output, that is. 2 watts at 100kV. 07-Aug-19 09:20 AM two watts dissipated in a transmission anode? 07-Aug-19 09:20 AM Yes! 07-Aug-19 09:20 AM that's impressive 07-Aug-19 09:20 AM At 40 microns to boot 07-Aug-19 09:20 AM Here's a BS10 07-Aug-19 09:20 AM https://i.spirit.re/pBLi5.JPG 07-Aug-19 09:20 AM It's an itsy bitsy version of the BS6 07-Aug-19 09:20 AM Not a single clue what it's rated at, what the voltage or current or focus are 07-Aug-19 09:20 AM I just got this adorable x-ray machine for cheap 07-Aug-19 09:20 AM https://i.spirit.re/QV42i.jpg 07-Aug-19 09:20 AM Issotiny 07-Aug-19 09:22 AM naww, cute 07-Aug-19 09:22 AM But I did get it to run 07-Aug-19 09:22 AM https://i.spirit.re/AvL9L.png 07-Aug-19 09:22 AM I believe I made it run in the worst possible conditions you could ever make it run 07-Aug-19 09:22 AM that detector looks digital 07-Aug-19 09:22 AM Indeed 07-Aug-19 09:22 AM a Hamamatsu C9732DT 07-Aug-19 09:22 AM 120x120mm single-wafer CMOS, 5.5MP 07-Aug-19 09:23 AM noice 07-Aug-19 09:24 AM I also have a Gendex GXS-700 07-Aug-19 09:24 AM But it's sad and dead 07-Aug-19 09:24 AM I can read it, but get no noise 07-Aug-19 09:24 AM Ah, found it. The ghettoray. https://i.spirit.re/9DBqc.jpg 07-Aug-19 09:24 AM When your x-ray tube can be run through a laptop CCFL inverter and a multiplier stack, you know you have a low power tube 07-Aug-19 09:24 AM It was running at so low of a voltage that I got no backscatter when I was standing at the door 07-Aug-19 09:24 AM But running any tube in the open makes you a not very smart person, so that was only a once-off test to verify that they work. 07-Aug-19 10:23 AM yep, that's a very... optimistic setup 07-Aug-19 10:23 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2019-08-02_20-32-24-258F7.jpg 07-Aug-19 10:23 AM but I can't say that we were any better... 07-Aug-19 10:32 AM I like the stand made out of dosimeters 07-Aug-19 10:32 AM That's the nuclear physics equivalent of putting your monitor on a stack of expensive physics books 07-Aug-19 11:36 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/snowglobe-9E0E8.avi 07-Aug-19 11:48 AM 300R/hr is quite a field 07-Aug-19 11:48 AM but then again I think that's Carl Willis, the guy who poked inside the Chernobyl plant for fun 07-Aug-19 11:49 AM yep, that's him 07-Aug-19 11:50 AM I may or may not get a ridiculous x-ray system in early September 07-Aug-19 11:50 AM 160kV, 250W, and a 6um focus 07-Aug-19 11:50 AM Continuously pumped with a turbo. 07-Aug-19 11:50 AM 330kg :< 07-Aug-19 11:55 AM oh my 07-Aug-19 11:55 AM where do you get all of that stuff from 07-Aug-19 11:55 AM and what do you do with that many x-ray sources 07-Aug-19 12:32 PM I don't know if I'll get this one 07-Aug-19 12:32 PM I advertised and someone reached out to send me a scrap unit that's leaky 07-Aug-19 12:32 PM I have NO x-ray sources 07-Aug-19 12:32 PM only 4 tubes 07-Aug-19 12:33 PM hehe 09-Aug-19 10:21 AM By the way, is anybody intrested in some russian PMTs and geiger counters? (also with berillium windows for Xray spectroscopy) 09-Aug-19 11:23 AM are you selling or offering info / pics? 09-Aug-19 11:48 AM i have some extra and can sell/exchange to vacuum stuff. 09-Aug-19 02:20 PM Oh I need some beryllium windows 09-Aug-19 02:20 PM Just small pieces of beryllium foils will do actually, need them to cover some small PIN diodes 09-Aug-19 03:05 PM Once I get around to a DIY x-ray tube, I'll want some windows too 09-Aug-19 09:51 PM Stay tuned. I may have some available. I wish I knew a year ago people wanted X ray tube parts. We packed it all away in storage units for the new owner and in a couple months when it all comes out they may be willing to part with some. We had beryllium foil, sheet, and I believe some already formed windows attached to ofc ports ready to seal. Also if you need leads and stems I have them here. Also matching nonex bulbs. 09-Aug-19 09:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-BE3A1.jpg 09-Aug-19 09:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-11737.jpg 09-Aug-19 09:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-259BF.jpg 09-Aug-19 09:51 PM Some tubes we used to make. 09-Aug-19 09:54 PM this is really cool 09-Aug-19 09:54 PM I want to manufacture ultra small spot size microfocus tubes 09-Aug-19 09:54 PM <10um ideally 09-Aug-19 09:54 PM Foil/sheet/windows are practically unobtainable, especially if thin. It'd be awesome to have a stock for experiments. 09-Aug-19 09:56 PM It’s somewhere in the boxes. We had a good amount too. 09-Aug-19 09:57 PM I've got a source on qnty 1 vacuum windows. About 4-500 depending on spec 09-Aug-19 09:57 PM $4 is fine 09-Aug-19 09:57 PM $500 isn't :P 09-Aug-19 09:57 PM Yeah it's high but at least they do it 09-Aug-19 09:57 PM I'm not looking to manufacture en masse, only a few for myself and people who can't obtain them otherwise 09-Aug-19 09:58 PM How large of a window do you need and what kind of flange? 09-Aug-19 09:58 PM I have no idea 09-Aug-19 09:58 PM As many as possible is the only criteria :P 09-Aug-19 09:58 PM Because I'll probably wreck a bunch 09-Aug-19 09:58 PM (I have never worked with Be foil) 09-Aug-19 09:59 PM Hold on. I have to go check something. 09-Aug-19 09:59 PM @AdamMcCombs do you have a source on stems? 09-Aug-19 09:59 PM That'd be a very useful thing to have 09-Aug-19 09:59 PM Glass to metal seals are a massive pain 09-Aug-19 10:14 PM I tried to look some things up on the SCHOTT website but once again they have changed things. Yes I have many boxes of stems and the equipment to make more 09-Aug-19 10:17 PM I'm building a high vacuum station right now 09-Aug-19 10:17 PM And have pretty much all of the parts for a torch system 09-Aug-19 10:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-B4AB3.jpg 09-Aug-19 10:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-64DCE.jpg 09-Aug-19 10:18 PM That's pretty much exactly what I need 09-Aug-19 10:18 PM But also pretty much exactly what I can't afford to buy or ship :P 09-Aug-19 10:18 PM This is one of the stations used to make the X ray tubes. Pretty basic 09-Aug-19 10:18 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-94FD6.jpg 09-Aug-19 10:18 PM Sorry about the mess 09-Aug-19 10:18 PM Looks fairly simple 09-Aug-19 10:18 PM Are the tubes still made? Sounds like it went under 09-Aug-19 10:18 PM I see a couple valves, the regular diffpump, forepump, and a filament flashing(?) supply 09-Aug-19 10:21 PM These are the gland fittings and the packings. These were made by a machine at near the factory. The manifold is copper silver brazed together 09-Aug-19 10:21 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-FE3E1.jpg 09-Aug-19 10:21 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-FADC4.jpg 09-Aug-19 10:21 PM Oh and I'm assuming at the top is a bakeout oven 09-Aug-19 10:21 PM Make the tube, seal them to the fittings, lower it, and bake to get the crap out 09-Aug-19 10:21 PM Then seal off 09-Aug-19 10:22 PM Correct. For hard glass tubes I bake at about 525C and sometimes spike it up to just at the annealing point. 09-Aug-19 10:22 PM Which glass do you use? 09-Aug-19 10:22 PM I don't fully recall at the moment but I know one tolerates heating/cooling cycles and funny expansion differentials, the other is fragile 09-Aug-19 10:22 PM borosilicate and soda lime was it? 09-Aug-19 10:23 PM Mostly nonex or soft glass. Just depends on what I am doing 09-Aug-19 10:23 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-FA09C.jpg 09-Aug-19 10:24 PM My goal is to try making numitrons first, then x-ray tubes 09-Aug-19 10:24 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-F7161.jpg 09-Aug-19 10:24 PM Stems for days 09-Aug-19 10:24 PM Or months in my case 09-Aug-19 10:24 PM Nonex tungsten sealing glass... huh 09-Aug-19 10:24 PM Well, it's borosilicate 09-Aug-19 10:26 PM I have 15,000 sets of 6AQ5 size 7 pin bulbs and stems. And about 4K 9 pin 12AX7 size 09-Aug-19 10:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-25A97.jpg 09-Aug-19 10:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-25F48.jpg 09-Aug-19 10:26 PM Sylvania and attention of 09-Aug-19 10:26 PM Those sets are older than me! :P 09-Aug-19 10:26 PM I guess I'll make a tiny bakeout kiln, just for one tube 09-Aug-19 10:26 PM But now that you've given yourself away, expect to get prodded with questions for insider knowledge! 09-Aug-19 10:30 PM Yeah. There was a half hearted attempt when Phillips bought sylvania and they moved everything from Emporium to Altoona that some of the critically essential types production capability be moved to MU who was already doing second source government tube work. The founder bought much of what was still useable on the surplus equipment market and lots of materials from sylvania to do sample batches of things. 5687’s 6c4’s and a few sweep tubes. 09-Aug-19 10:31 PM I'd be interested in buying a few sets of stems and maybe the glass tubes, plus the window stuff, once I get my high vacuum system working 09-Aug-19 10:31 PM Single tube bakeout oven is hard cause they sometimes heat too fast. We tried it and did get it to work but it was not easy. 09-Aug-19 10:32 PM I can implement a closed loop controller 09-Aug-19 10:32 PM Regulating power to get the right rate 09-Aug-19 10:32 PM Tube making is going more and more extinct each day, and while I don't have an interest in the audiophile stuff, making stuff that might still be useful(x-rays) or pretty(numitrons, nixies) today is definitely of interest to me. 09-Aug-19 10:33 PM It’s more the thermal characteristics of the chamber itself. I would use like a PWM or some other kind of variable current drive for the heating elements to slowly ramp up and down. Not unlike a reflow controller 09-Aug-19 10:34 PM Yeah, that's what I was thinking of 09-Aug-19 10:34 PM I'll probably use IR heating elements 09-Aug-19 10:34 PM Since glass is opaque(and quite shiny) in LWIR 09-Aug-19 10:34 PM Also old fashioned variac is quite useful 09-Aug-19 10:34 PM I have a variac here 09-Aug-19 10:34 PM It's rugged, soviet, hums a lot, and has been a house for one too many spiders, but it still chugs along 09-Aug-19 10:35 PM No. Use kanthall elements or like small oven elements. 09-Aug-19 10:35 PM IR heaters are oven elements in quartz tubes 09-Aug-19 10:35 PM I have a pile of slightly cracked ones from a massive industrial extruder 09-Aug-19 10:35 PM Don’t use them. They preferentially heat the metal seals and crack the tube 09-Aug-19 10:35 PM ah 09-Aug-19 10:35 PM well, regular oven heating spiral then 09-Aug-19 10:35 PM a bit of PWM control, with zone sensing to ensure even heating 09-Aug-19 10:36 PM Kanthal elements in ceramic bushings 09-Aug-19 10:36 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-2EAEA.jpg 09-Aug-19 10:36 PM I'll probably use high temperature fire brick 09-Aug-19 10:36 PM After some gentle cooking for a day or two they become brittle but very resistant to high temps 09-Aug-19 10:38 PM Glo bar used in the soft glass station. The shield I am holding out of the way is required to keep the glass from melting from direct heat radiating. You want a smooth consistent heat 09-Aug-19 10:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-70D26.jpg 09-Aug-19 10:38 PM I could put a metal tube between the actual glass and the heater element 09-Aug-19 10:38 PM Would probably even out the temps as well 09-Aug-19 10:38 PM What's the time frame on the ramp and bakeout time? 09-Aug-19 10:41 PM Other items you will need is a reduction atmosphere furnace. I like quartz tube types cause they heat and cool down fast and you can see what’s happening. Tilt then at an angle so the hydrogen pushes out the air and with diameters up to two inches you can just burn the excess hydrogen flow off as an open pale flame. Otherwise you need weighted muffles with inert gas blowers at the ends 09-Aug-19 10:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-D1C60.jpg 09-Aug-19 10:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-C6C3C.jpg 09-Aug-19 10:42 PM quartz tube ovens are painfully expensive 09-Aug-19 10:49 PM These stations are sorted out pretty well. Generally a exhaust cycle on a already hot and too proper vacuum level station, which is in the -7 range for the larger one and top end of the -6 range for the little one (which is about as good as you can do with rubber or buna seals for the tube ports) about 2 hours is the cycle time is rushing. 3 is what I normally do. It takes about 30 minutes to come up to temp and depending on construction I leave it there from 30 minutes to a few hours for tubes with ceramic spacers. Then about 40 minutes to come back down cool enough. I usually give a quick induction heat before bake out. It seems to help get the ball rolling as far as outgassing metals go. The glass gives off so much water vapor and since it heats faster than the internal parts much of it can re condense in them so I want them cleaned a bit first so there is no spotting. After bake out the big RF bombing takes place, and then filament lighting, then another bombing with the filaments lit, then flash the filament for whatever treatment it needs and then back to just above operating voltage for the final bombing, the. Tip off and getter flash. If there are other tubes on the Manifold I will give a quick additional flash and bomb before tipping them off too 09-Aug-19 10:49 PM Get a Chinese quartz tube used on patio heaters. They are silly cheap 09-Aug-19 10:51 PM The first thing is getting to -7 09-Aug-19 10:51 PM Now here's a question I've been brooding over 09-Aug-19 10:51 PM Ever had the tubes fail catastrophically in terms of vacuum? 09-Aug-19 10:52 PM Happens all the time 09-Aug-19 10:52 PM I have a turbopump system, so if it fails somewhere mid-pumpdown, I no longer have a turbopump system 09-Aug-19 10:53 PM Stress crack or pin seal fail or cold seal or just a freak accident. Sometimes they get too hot and collapse or vibrations break the exhaust tubeulation. 09-Aug-19 10:53 PM That’s why I only will ever use diffusion pumps and no tube factory ever used turbos. Also they have a really hard time with the gas load of a tube unless you get a super expensive one. 09-Aug-19 10:54 PM Mine is only rated at 56l/s 09-Aug-19 10:54 PM But it's tiny 09-Aug-19 10:54 PM And very fast 09-Aug-19 10:56 PM Extra 2” pumps. Theese were the mainstay of the tube and crt industry. Either the Consolidated vacuum Corp MCF-60 or the NRC H-2-P pumps backed by a dual seal two stage rotary pump. 09-Aug-19 10:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-3C1BA.jpg 09-Aug-19 10:56 PM Some people have christmas lights 09-Aug-19 10:56 PM Others have diffpumps 09-Aug-19 10:59 PM We threw out about 50 of them. Kept the best looking ones. After DC 704 fluid came out they didn’t even bother putting valves on the systems. Just shut the rotary pump off after tip off, hit an air admittance bleeder pull out the remaining glass tube, shove in the new one to exhaust, turn the rotary pump back on and back into the bake out like it would go. 09-Aug-19 10:59 PM That was for CRT’s 09-Aug-19 11:00 PM Should've kept them 09-Aug-19 11:00 PM Now it's a hobbyist goldmine :P 09-Aug-19 11:01 PM I tried for 5 years to get hobbyists to come get the stuff. We would have given a lot of it away, but because it was not modern they all turned their noses up at it 09-Aug-19 11:01 PM "I'd like a brand new 500l/s turbopump for the price of a KF40 flange" 09-Aug-19 11:01 PM Diffpumps are indestructible, I do sometimes regret not buying one 09-Aug-19 11:03 PM Dozens have come to@me and wanted to learn how to make tubes but they never listen. Once they find out it’s hard work and not a cooking recipie they loose interest. Just because you put the parts together properly does not@mean they will work. I could never get them to understand that. It’s years of development with statistical analysis of minute incremental changes 09-Aug-19 11:03 PM I know pretty much nothing but the basics about making tubes 09-Aug-19 11:03 PM But I've yet to step on the road of exciting garden rakes 09-Aug-19 11:05 PM The people who bought all the stuff are going to make a try of it, but I got myself set up in my garage years ago just in case. 09-Aug-19 11:05 PM And a stock to single-handedly revitalize the audiophool market 09-Aug-19 11:07 PM No real interest in that. They are all too silly. Now fun early day stuff for playing around with or RF stuff I am more interested in. I just realized everybody else here will be mad for us blabbing on in the radiation post. Time for bed anyways 09-Aug-19 11:07 PM Yeah, same here 09-Aug-19 11:07 PM My goal is to make a practical microfocus x-ray tube 09-Aug-19 11:07 PM Tough 09-Aug-19 11:07 PM ~100kV, ~10-20um, a couple watts at most 09-Aug-19 11:07 PM Enough to fully utilize the detectors I have 09-Aug-19 11:08 PM Something to aspire to 09-Aug-19 11:08 PM Good night 09-Aug-19 11:08 PM Good night 10-Aug-19 01:10 AM you could build a fancy bong out of the 2" diffusion pumps 10-Aug-19 08:50 AM Hmmmmm... not sure the dynamics would be quite right, but people have made them from lesser things! I think a glass pump would work better! Hahahaha. Actually when I was selling the glass lathes off the directive was try to find customers who would use them for lab or tube work and give them a deal before selling to the bong and pipe people 10-Aug-19 09:29 PM diffusion pumps are tuned for supersonic flow dynamics 10-Aug-19 09:29 PM you'd have to pull Real hard 11-Aug-19 08:23 AM i mean using them as a bong 11-Aug-19 08:23 AM not diffusion pumping the bong thing 11-Aug-19 08:23 AM no suicide just use them as a bong! 12-Aug-19 08:29 PM Anybody want any thorium oxide? I unfortunately found some here in a box of other stuff. There is about two pounds and I would prefer not to have my house turned into a super fund site! I made sure it’s safe. Made up a lead box and it’s all in well sealed original jars or in earthenware rolling mill containers. Outside the lead box it’s still putting off .1 mR/hr at about 6 inches. Hot stuff for an alpha emitter! 12-Aug-19 08:29 PM Build your own project thoria nuke plant! Hahahaha 12-Aug-19 08:30 PM That's a lot of ThO2 12-Aug-19 08:30 PM Yes it is. It’s probably a problem here in California 12-Aug-19 08:31 PM oh it's 100% guaranteed to cause cancer in the state of California 12-Aug-19 08:31 PM :P 12-Aug-19 08:31 PM Don’t get me started. We now have 10 employees so we meet the threshold that we need to start prop 65 labeling everything 12-Aug-19 08:31 PM but it's not really that dangerous, as long as you don't Goiana incident yourself 12-Aug-19 08:32 PM I was even going to see if any brokers want to buy it. I hear it’s super rare theese days 12-Aug-19 08:32 PM oh dear no 12-Aug-19 08:32 PM I'm almost entirely sure that this quantity is way more than the unlicensed limit 12-Aug-19 08:32 PM even in the US 12-Aug-19 08:32 PM so unless it's regulated and you have licensing for it, shush about it :P 12-Aug-19 08:33 PM Hahaha 12-Aug-19 08:34 PM I have a few grams of ThO2, but sintered into tungsten 12-Aug-19 08:34 PM hot enough to set off my radiation pager from ~30cm away 12-Aug-19 08:34 PM I also have a bit of Sr-90+Y-90 and even less Am-241 12-Aug-19 08:34 PM a good enough-ish set to calibrate my spectrometers 12-Aug-19 08:34 PM though it's in dire need of Cs-137 and Co-60 sources 12-Aug-19 08:34 PM but getting those while staying under the legal limit is hard, as most are rather angry 12-Aug-19 09:02 PM Just read the laws. It’s actually not so bad. I am under any amount where the really bad stuff would happen regulation wise. After a second look too I don’t have that much. Realistically about a half pound. 12-Aug-19 09:02 PM If memory serves limit is around 15lbs? 12-Aug-19 09:02 PM It’s worth a freaking fortune, but I can’t sell it. I could get a liscence to handle it 12-Aug-19 09:02 PM Actually 2 pounds per year 12-Aug-19 09:03 PM I must be thinking for uranium 12-Aug-19 09:03 PM Is the NRC limit for thorium. Of course thorium dioxide will have a much lower content 12-Aug-19 09:03 PM There is a guy selling it on eBay for a fortune, however I just pulled up the rules he is siting and he was a warped understanding of that document 12-Aug-19 09:03 PM But then again most hucksters are not science or regulatory literate anyways 12-Aug-19 09:03 PM Essentially sitting in a lead box In my garage is not illegal. 12-Aug-19 09:06 PM oh charles you're in california? do you mind if I ask whereabouts? 12-Aug-19 09:06 PM Hahahahaha.... wait a second...... 12-Aug-19 09:06 PM Central 12-Aug-19 09:07 PM I'm in the south bay area 12-Aug-19 09:07 PM You want it? 12-Aug-19 09:07 PM no, no 12-Aug-19 09:08 PM Darn 12-Aug-19 09:08 PM just curious, I haven't seen many californians on this server 12-Aug-19 09:08 PM qualia is the only other I know of 12-Aug-19 09:09 PM Anybody with a standard liscence can have it. Somebody from a university lab or other research lab can have it and can legally just take it away 12-Aug-19 09:09 PM You just can't sell it? 12-Aug-19 09:11 PM Not sure. If anybody has any insight let me know. I know thorium metal is very illegal to sell. But I see no rules about thorium oxide 12-Aug-19 09:11 PM But I never like being in the gray area when it comes to Gray exposure (ok, nerd joke) 12-Aug-19 09:11 PM I think you should reach out to Twitter's radiation/laser safety officer 12-Aug-19 09:12 PM ????? 12-Aug-19 09:12 PM Who is that? 12-Aug-19 09:12 PM Check out Funranium Labs (@funranium): https://twitter.com/funranium?s=09 12-Aug-19 09:17 PM Message sent to him 12-Aug-19 09:17 PM Oh. Just found another document. I’m all good. 3.3 pounds is the limit for an industrial firm (which I am) to possess 12-Aug-19 11:12 PM He was able to confirm what we found and make a good suggestion who to call if I want to get rid of it. 12-Aug-19 11:49 PM So you basically just fond the stuff lying around? 13-Aug-19 12:17 AM @Charles I KNOW WHAT YOU CAN DO 13-Aug-19 12:17 AM make check sources! 13-Aug-19 12:17 AM you're allowed to process it as well as possess, right? 13-Aug-19 12:17 AM because if you process it down to the uCi/source level, you have yourself a couple thousand dollars worth of worldwide-shipping-safe thorium check sources for hobbyists 13-Aug-19 12:17 AM the way I'd do it is just acrylic disks with small holes in them 13-Aug-19 12:17 AM drop a tiny bit in(measured of course, maybe a screw dosing thing), then carefully pour second acrylic layer on top 13-Aug-19 12:17 AM maybe a pin head worth of air inside just to account for the eventual buildup of radon 13-Aug-19 12:17 AM there was a seller on ebay that sold close to 100 sources that way before stopping 13-Aug-19 12:17 AM 2 lbs of ThO2 is ~6435kBq or ~173uCi 13-Aug-19 12:17 AM so you have enough for ~1700 sources (legal to own and ship worldwide, more or less), minus some losses and keeping some 13-Aug-19 12:17 AM 1700 sources, at what... $10 each, I reckon? 13-Aug-19 12:17 AM do the math :P 13-Aug-19 07:01 AM The thought had occurred to me. That is pretty much the only reason I would keep it. I would probably do it in glass ampoules. I have the means to make those. 13-Aug-19 09:13 AM Glass is fragile 13-Aug-19 09:13 AM But you could, yeah 13-Aug-19 09:13 AM You don't want it to be thick walled tube, since Th is a very weak emitter 13-Aug-19 09:43 AM If it's old it will have daughters that spit out beta and gamma. 13-Aug-19 09:50 AM all thorium is old 13-Aug-19 09:50 AM it's all in an equilibrium 13-Aug-19 09:50 AM unless it was chemically separated 13-Aug-19 10:38 AM I've seen check sources suggested before, Ampouled and then sealed in epoxy. Sounds like a decent plan to me. 13-Aug-19 10:38 AM I've just checked the local laws and if you can ship internationally I'm interested 13-Aug-19 11:23 AM Same 13-Aug-19 11:47 AM Few messages back adam asked if I found it. In a manner of speaking yes. It was in a box of things given to me and I did not expect it to be in there. Some years back a friend decided I should have all of his materials for producing particular rectifier tubes with bonded thoria filaments. We had been buying the filaments pre coated from a vendor so I was not expecting to see bottles of it. 13-Aug-19 11:49 AM Wow. 13-Aug-19 11:49 AM the bottles can live a new life as hobbyist check sources 13-Aug-19 11:49 AM those are often lacking 13-Aug-19 11:50 AM I've not heard of bonded thoria filements, only alloy wires. 13-Aug-19 11:50 AM same as yttria I'm guessing 13-Aug-19 11:51 AM That's not one I know either. Alkali earth oxides I recognise. 13-Aug-19 11:52 AM yttrium oxide coated filaments are very common 13-Aug-19 11:52 AM in vacuum tubes, in vacuum gauges 13-Aug-19 11:52 AM the IGM-400s sold on ebay mostly come with yttria filaments 13-Aug-19 11:52 AM more robust, longer life, and they survive a few atmosphere vents before popping 15-Aug-19 07:30 AM Yittria replaced thoria about 25 years ago in bonded applications. Thoria bonded to tungsten wire is nearly as efficient as some dual carbonate sprayed filaments. Also running at saturation does not destroy it. It can recover. Yittria is nearly as good of an emitter but does not have the high peak of thoria. 15-Aug-19 07:30 AM I am currently working on a Yittria bonding process I would like to eventually use in RF linear amplifier tubes 15-Aug-19 01:00 PM Nice, homebrew or refurbed RF PA tubes? 15-Aug-19 01:00 PM Gave away my 4CX5000A to a friend for the price of a beer 17-Aug-19 02:39 AM https://twitter.com/Mach1ne_4423/status/1162574773970358272?s=09 17-Aug-19 02:41 AM So what is this? 17-Aug-19 02:41 AM I saw this and I don't get it? 17-Aug-19 03:08 AM Nvm just found @qualia 's thread 17-Aug-19 03:08 AM https://twitter.com/profanegeometry/status/1074784476448710656?s=19 17-Aug-19 03:13 AM i still want one of those shirts 25-Aug-19 02:24 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/0491964b85aecc99-3E9EC.png 31-Aug-19 02:11 PM http://theconversation.com/when-energy-drinks-actually-contained-radioactive-energy-67976 01-Sep-19 08:46 PM Probably available next to Cocaine, heroin, laudanum, and morphine at the corner drug store or soda fountain! 03-Sep-19 03:29 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7F48E.png 03-Sep-19 05:25 AM yeah 03-Sep-19 05:25 AM they did stuff in the 1950s 03-Sep-19 05:25 AM "loosed into the room" 03-Sep-19 05:25 AM like weak aim at the pee station 03-Sep-19 05:30 AM UPPU? 03-Sep-19 05:16 PM Hey if you saw that in the 50’s you’d probably be pretty impressed? 03-Sep-19 11:16 PM <__ice9#6039> Oh. I have a kilogram of thorium dioxide that I bought for ceramics work. I'm not sure how I would manage to use it all, though-- that was just the minimum order quantity. 03-Sep-19 11:16 PM <__ice9#6039> Thorium dioxide is entirely legal to sell as long as you stay below the per-purchaser limits and keep records. Importing it is easy. Exporting it is much harder, though-- lower limits, etc. Looks like an attempt to keep the element in the country. 03-Sep-19 11:16 PM <__ice9#6039> It's useful as a super-high-temperature insulator in solid state conductive-ceramic devices. In this case, I bought it for making little tubes to hold the connections to yttria-stabilized zirconia Nernst heater elements, mainly 03-Sep-19 11:16 PM <__ice9#6039> Sintering requires very high temperatures, though. It's best to sinter electrically once it is already white hot. 03-Sep-19 11:16 PM <__ice9#6039> I ran some experiments with so-called 'spark plasma sintering' (it's just Joule heating) on zirconia and succeeded in fusing it and making some small single crystal cubic zirconia pieces, but the heating is very non-uniform unless the piece is already hot enough to conduct reasonably well on its own 03-Sep-19 11:16 PM <__ice9#6039> Required voltage and current levels are also quite high 03-Sep-19 11:16 PM <__ice9#6039> Voltage to overcome the high initial resistance of the ceramic material until the current heats it up much hotter 03-Sep-19 11:16 PM <__ice9#6039> Best done with a current limited source like a welding power supply running through a big fat diode to protect it until the initiation voltage has a chance to heat it up to lower the resistance. 03-Sep-19 11:16 PM <__ice9#6039> Anyway you basically need a fairly high end furnace to do anything useful with this material, but it has quite remarkable capabilities if you do 03-Sep-19 11:16 PM <__ice9#6039> It is a lot less tough than YSZ though. Granted not as bad as alumina or magnesia. Try not to thermally stress it too much unless you can afford some cracking within its intended space of use. Like if the surrounding walls would hold it together anyway. I've thought about just using the powder directly as filler for that insulation use case, but it's awkward because of the bottom of the ceiling mounted tubes. Floor ones are ok. 03-Sep-19 11:41 PM @__ice9 we had this exact discussion with Charles a while ago, scroll up! 03-Sep-19 11:41 PM TL;DR: Make cheap barely active check sources that can be shipped worldwide safely. 03-Sep-19 11:41 PM (<0.1uCi is safe in 99% of the world) 03-Sep-19 11:41 PM No sintering required, just epoxy pucks. 04-Sep-19 12:44 AM <__ice9#6039> Ah yes I posted in response to this actually 04-Sep-19 12:44 AM <__ice9#6039> Actually that makes me think of also maybe using it in some kind of composite with zirconia hmm. But the powder would have to be much finer. And I don't like fine-ground alpha emitters. Maybe leaching it into acid and re-precipitating with zirconia might work though. 04-Sep-19 12:44 AM <__ice9#6039> Boiling zirconia in hydrochloric acid for several days does produce some apparent zirconyl chloride and related species, but most remains undissolved. Leaching thoria in a mixture of nitric and hydrofluoric acids also seemed to put something into the solution but not very much.... Refluxing stuff in HF is too difficult with my current vessels though, so that corner of the search space remains unexplored. 04-Sep-19 12:44 AM <__ice9#6039> Needs more research. These refractory ceramics are extremely chemical resistant, vaguely comparable to silica. 04-Sep-19 12:44 AM <__ice9#6039> Fused alkali might work but would introduce undesirable alkali metal contamination. 09-Sep-19 01:25 PM I suddenly remembered this. Does anyone want absolutely unregulated, extreme quantities of Po-210 shipped to your doorstep? I present to you, the Staticmaster. Up to 500uCi for a 1" emitter. https://amstat.com/products/staticmaster-1u200-1-ionizer.html 09-Sep-19 01:25 PM Kind of insane if you think about it... 09-Sep-19 01:26 PM too bad they're not sold outside of the us :< 09-Sep-19 01:27 PM eBay is your friend 09-Sep-19 01:27 PM as long as you can find a fresh unit 09-Sep-19 01:28 PM there are some on ebay, but only years old 09-Sep-19 01:28 PM at least last time I checked 09-Sep-19 01:28 PM and there are some things I really don't want to explain to customs 09-Sep-19 01:29 PM lol they're sold on Adorama 09-Sep-19 01:29 PM https://www.adorama.com/cpsmr3.html 09-Sep-19 01:29 PM ha 09-Sep-19 01:29 PM this is absolutely insane 09-Sep-19 01:29 PM polonium, just sold free for all 09-Sep-19 01:31 PM this makes me Wonder why some people struggle to find a Neutron source :D 09-Sep-19 01:31 PM because they're dumb and it's good that they struggle 09-Sep-19 01:32 PM Fair enough 10-Sep-19 02:21 PM it seems like nuclespots are the usual thing for hobbyist neutron sources, and they're 5 mCi 10-Sep-19 02:21 PM but, yeah, general license 10-Sep-19 02:21 PM i tried a thing with a sliver of beryllium and a smoke alarm button and .. it wasn't incredibly conclusive, tbh, but on the right track certainly 10-Sep-19 02:21 PM kinda wanna make a little vacuum chamber for it 10-Sep-19 02:23 PM smoke alarms usually have 1 uCi or less, that would result in one or two neutrons per second 10-Sep-19 02:26 PM would be interesting to see if i can use the 35+ in MCS mode to detect its presence, even at such low activity 10-Sep-19 02:26 PM honestly maybe not, but might as well give it a try 10-Sep-19 02:26 PM otoh, beryllium as a photoneutron target.. 10-Sep-19 02:29 PM 35+? 10-Sep-19 02:30 PM I got a Canberra Series 35+ MCA/MCS from a fusor friend 10-Sep-19 02:30 PM i think it needs some recapping work done, but 10-Sep-19 02:30 PM ohh, congrats! 10-Sep-19 02:30 PM ^.^ 10-Sep-19 02:30 PM well mca or just simple trigger should not matter in detecting low activities 10-Sep-19 02:30 PM or, hm 10-Sep-19 02:30 PM if you use a Gamma detector and only look at the 59 keV line 10-Sep-19 02:30 PM that might work 10-Sep-19 02:34 PM i couldn't sleep last night so i tried wrapping up one of my 3" scintillators, but it turned out to be super light-leaky... and my one little scintillator i was using is definitely in need of resurfacing 10-Sep-19 02:34 PM so i need to get a bunch of electrical tape and more cardboard tubes 10-Sep-19 02:34 PM and then mmmmaybe i might have a gamma scintillator 10-Sep-19 02:34 PM that or i take the crystal you sent me and hammer it into the case of the original damaged-scintillator PMT housing i was using.. 10-Sep-19 02:34 PM they might actually be the same diameter, which'd be neat 10-Sep-19 02:35 PM good luck with that, please refrain from using hammers on scintillators :D 10-Sep-19 02:36 PM :D 10-Sep-19 02:36 PM i'm also curious if the 3He counter looks any different on an MCA 10-Sep-19 02:36 PM any different as opposed to what? 10-Sep-19 02:36 PM i have no idea how people managed to do meaningful spectroscopy with just SCAs 10-Sep-19 02:36 PM just an oscilloscope and a pulse counter 10-Sep-19 02:37 PM well, you'll get a spectrum, see the wall effect, etc 10-Sep-19 02:37 PM i figure real neutron activity will all settle around a single channel 10-Sep-19 02:37 PM taking a Spektrum with an SCA is easy, you set up one channel, count events over some time, move the channel one width over, count, move, etc 10-Sep-19 02:37 PM it's like those old scopes using some Megasamples per second for GHz signals 10-Sep-19 02:37 PM nope, He3 has a very characteristic spectrum 10-Sep-19 02:39 PM oh really 10-Sep-19 02:39 PM energy-dependent? 10-Sep-19 02:39 PM that and the boron tube, too, which i haven't fired up in a minute 10-Sep-19 02:40 PM nope 10-Sep-19 02:40 PM Whoa, Amstat have tons of other sources 10-Sep-19 02:40 PM up to 740MBq 10-Sep-19 02:40 PM o_O 10-Sep-19 02:40 PM Do these require a license? I can't imagine they don't require a license 10-Sep-19 02:41 PM the spectrum comes from the He Splitting, and one fragment crashing into the wall, not delivering any energy to the gas 10-Sep-19 02:41 PM there's probably some threshold above which it goes from being a general-license'd thing that you need to, like, promise to send back in a year, to a specific license, at which point you might need to like submit usage reports or have inspectors wander through your living room or w/e 10-Sep-19 02:41 PM https://amstat.com/esd-ionizer/p2031-nuclecel-end-of-line-ionizer/ 10-Sep-19 02:41 PM holy hell 10-Sep-19 02:41 PM almost a GBq 10-Sep-19 02:41 PM for $400 10-Sep-19 02:42 PM it's like a tube furnace but for helium implantation :D 10-Sep-19 02:44 PM I really didn't know that you could buy such stupidly powerful sources in the US 10-Sep-19 02:44 PM with a simple signed paper slip 10-Sep-19 02:44 PM no NRC approval 10-Sep-19 02:44 PM @qualia this is what a He3 spectrum looks like 10-Sep-19 02:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/spektr_en_0030_Helium-13-90-8-A2990.png 10-Sep-19 02:44 PM the first peak is the lower energy fission product being stopped by the wall, the second is the higher energy product stopped and the big one is both depositing their energy into the gas 10-Sep-19 02:52 PM oh wow, huh 10-Sep-19 02:53 PM Boron is similar 10-Sep-19 02:53 PM but higher energy iirc 11-Sep-19 12:45 AM I revisited that page 11-Sep-19 12:45 AM https://amstat.com/products/mini-ionizer-blower-kit-with-ionizer.html 11-Sep-19 12:45 AM Accidently clicked on this link 11-Sep-19 12:45 AM ... just look at the description 11-Sep-19 12:45 AM you can order this without a license or signature 11-Sep-19 01:13 AM ... 11-Sep-19 01:13 AM wow 11-Sep-19 01:13 AM if you turn the fan off, do you still feel gentle breeze of He coming out of it? 11-Sep-19 08:55 AM Wow. That is surprising. You can’t walk out of a building with alcohol or a glass drinking cup but you can buy a potentially deadly poisonous radioactive device with nothing more than good faith and money. Hahahaha 11-Sep-19 08:55 AM In the words of Yakov Smirnoff “What a Country” 11-Sep-19 09:03 AM I bough an analytical balance a few years ago that had a polonium ionizer in it. 11-Sep-19 09:04 AM too bad that will have decayed by now 11-Sep-19 09:06 AM It was a year or two past its expiration date. 11-Sep-19 09:07 AM maybe you could replace it with an Am button from a smoke detector 11-Sep-19 09:52 AM The polonium ionizers are much much more active 11-Sep-19 09:52 AM An Am button is ~0.1uCi 11-Sep-19 09:52 AM those are several mCi 11-Sep-19 09:52 AM ... a wall of Am buttons would work 11-Sep-19 09:52 AM but it'd also be not insignificant amounts of gamma then 11-Sep-19 07:22 PM As an alternative to Krypton 85 some regulator tubes used Radium impregnated foil as a quick ion source. This is a print from 0A2WA and 0B2WA regulator tubes from Chatham electronics 11-Sep-19 07:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-6CC5A.jpg 11-Sep-19 07:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-215DD.jpg 11-Sep-19 07:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-5D2A5.jpg 12-Sep-19 02:07 AM those 0B2 also used different radioactive sources as far as i'm aware 12-Sep-19 02:07 AM also not all of them 12-Sep-19 02:07 AM i have a selection of different 0B2, one of them is active enough to see something with my pancake probe, two are only slightly above background and one is completely inactive 12-Sep-19 07:04 AM Digging further I found that generally the WA versions which denote ruggedized typically military versions used the radium strip while most regular versions used A tiny bit of KR 85 in the gas mix. Earlier tubes used neither but had weaker starting characteristics. May have required higher starting voltages in other words. I see how in the 60’s the specs tightened up considerably and they were guaranteeing starting at 120% regulation voltage. You need an ion source for that. Otherwise it’s more like 150% starting voltage or higher and wildly variable. 12-Sep-19 07:05 AM the radioactive components in stabilizer tubes were mainly for better ignition in the dark iirc 12-Sep-19 07:16 AM Is not that what I said?? Hahahaha. Am I too long winded for people to read what I write? 12-Sep-19 07:17 AM not for people, just for panda 12-Sep-19 07:19 AM you said voltage, i said dark 12-Sep-19 07:19 AM don't see where that's the same thing, but ok 12-Sep-19 10:58 AM hier sind immer alle am strahlen 12-Sep-19 11:10 AM für eine strahlende Zukunft! 16-Sep-19 04:03 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190915_182652-4DD37.jpg 16-Sep-19 04:03 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190915_182719-74CCE.jpg 16-Sep-19 04:03 AM and today on "recognize the detector" 16-Sep-19 10:19 AM oh oh oh oh oh i know what it is! 16-Sep-19 08:03 PM Ahhhhh.. A strangelet detector. I love those things. 17-Sep-19 01:39 AM Ehh, Close enough :D 17-Sep-19 07:24 AM I watched the Chernobyl series last week, anyone else watch it? 17-Sep-19 07:27 AM @GigaSquirrel did 17-Sep-19 07:28 AM Aye 17-Sep-19 07:41 AM and I still regret doing so 17-Sep-19 10:11 AM It's a wonderfully shot series, just very inaccurate in a lot of places 17-Sep-19 10:11 AM But it is a docudrama, not a documentary 17-Sep-19 10:13 AM more drama than docu 18-Sep-19 06:48 PM Agreed. But it was a good watch. Anybody who really cares about what happened can read all about it. It did however perfectly encapsulate Soviet mentality. We are infoulable, therefore we must be right no matter what the facts or situation actually are. Beginning to sound like our modern attitudes I think. 19-Sep-19 10:25 AM ah, i could post today's success here, too 19-Sep-19 10:25 AM from right to left: ludlum 12, ludlum 12, ludlum 5, ludlum 43-4 proportional detector, ludlum 3 with 44-9 19-Sep-19 10:25 AM both 12 seem to work the prop detector also apparently does its job quite well, the 5 is partly broken. got those 3 counters today. the 3 and the 44-9 are working just fine, have them since april. 19-Sep-19 10:44 AM hey I know these! 19-Sep-19 11:08 AM That's a lotta ludlums 19-Sep-19 11:10 AM and not even every one we have. there are a model 177 and more prop counters... somewhere else. :-D 19-Sep-19 11:15 AM and another model 3 19-Sep-19 11:16 AM oh sorry, that's a model 2 in the video, not a 3 19-Sep-19 11:16 AM right 19-Sep-19 11:16 AM hah, you wish! 19-Sep-19 11:16 AM but now that I have my model 12 I can mod my model 3 19-Sep-19 11:17 AM mod for what? 19-Sep-19 11:18 AM proper amp, signal out, stuff like that 19-Sep-19 08:39 PM Is it being paranoid to at least monthly flip on your model 3 and 44-9 and just do a quick sweep of the house and maybe a little in the yard? You know. Just in case? 19-Sep-19 08:39 PM For you know. Reasons.. 19-Sep-19 08:44 PM Prudent maybe? 20-Sep-19 10:20 AM i leave mine on 24/7 and give dusty areas/air filters/workspaces a look over every once in a while, just 'cos 20-Sep-19 10:20 AM random new ebay nim module or weird conflat? sure, a sweep can't hurt 20-Sep-19 10:20 AM usually not like.. the backyard and rest of the house tho 20-Sep-19 10:21 AM random ebay nim module comes back with sparkly copper or brass 20-Sep-19 10:21 AM also, did you know that tubes have a lifespan @qualia 20-Sep-19 10:21 AM PMTs too 20-Sep-19 10:23 AM mhm! i have wondered about getting a new 44-9 to compare performance to this one 20-Sep-19 10:23 AM which has been running continuously since i bought it in early 2018 20-Sep-19 10:23 AM albeit in a low count rate bg environment 20-Sep-19 11:11 AM Should last as long as it does not get punctured or leak. The gas inside is stable indefinitely I believe 20-Sep-19 11:22 AM the tubes have a set lifetime of pulses 20-Sep-19 11:22 AM it's into the timestentothes 20-Sep-19 11:22 AM but it's still finite 20-Sep-19 12:55 PM 10^10 imps is the usual rated lifespan for a GM tubes 20-Sep-19 12:55 PM @Deleted User what's the limiting factor in PMTs? 20-Sep-19 12:57 PM something to do with the PMT lifetime, but I'm not entirely sure 20-Sep-19 12:57 PM but at least the projected lifespan of good PMTs is into the decades, if not into tens of decades 20-Sep-19 12:58 PM only failure for PMTs I know (apart from physically breaking) is the cathode or anode dying due to too high current 20-Sep-19 12:58 PM the current is always there 20-Sep-19 12:58 PM so it's gradual during normal operation 20-Sep-19 12:59 PM but how would a few nA hurt the tube 20-Sep-19 12:59 PM I don't know 20-Sep-19 12:59 PM all I know is that their lifetimes are not physically infinite, but practically infinite 20-Sep-19 12:59 PM ok ^^ 20-Sep-19 01:00 PM soviet PMTs died after only a few thousand hours 20-Sep-19 01:00 PM the very old ones 20-Sep-19 01:00 PM what was their failure mode? 20-Sep-19 01:01 PM I think their characteristics went all wonky 20-Sep-19 01:01 PM gain drifted, current drifted 20-Sep-19 01:01 PM oh, lol 20-Sep-19 01:03 PM I want a huge scintillator 20-Sep-19 01:03 PM I have a FEU-49B 20-Sep-19 01:03 PM 150mm diameter photocathode 20-Sep-19 01:03 PM it's NIB 20-Sep-19 01:04 PM get some 150*150 mm slab of Li enhanced brilance 20-Sep-19 01:04 PM well, NUT 20-Sep-19 01:04 PM new under table 20-Sep-19 01:04 PM no box 20-Sep-19 01:04 PM getting large pieces of scintillator is really expensive 20-Sep-19 01:04 PM even plastic is 20-Sep-19 01:05 PM yep 20-Sep-19 01:05 PM like hell 20-Sep-19 01:05 PM ... group buy? 20-Sep-19 01:05 PM https://www.ebay.com/itm/Bicron-BC412-42-X-12-X-2-1-4-Scintillator-Plastic-w-Scintillation-Detector/283446590006? 20-Sep-19 01:05 PM who would have guessed fabricating huge single crystals would be expensive :D 20-Sep-19 01:06 PM 1066x304x60mmish chunk of BC412 20-Sep-19 01:06 PM for $500 20-Sep-19 01:07 PM I Wonder how bad self Absorption is in that piece 20-Sep-19 01:15 PM probably pretty severe 20-Sep-19 01:15 PM these are used as very sensitive personnel monitors 20-Sep-19 01:15 PM been there, made them go into alarm :P 20-Sep-19 01:15 PM but we had to get those barrels out there somewhere 20-Sep-19 04:00 PM Re:PMT lifetime, the amplification is from a very thin layer of secondary emitter. In the case of oxidised surfaces like CsSbO I think atomically thin. This gets damaged in use by the charge. The higher the current a PMT is run at, the sooner later stages of amplification lose gain. Effective life can be extended by increasing the voltage a little and taking the pulse from an earlier dynode (which will have seen less charge hitting it). The pulse will be the opposite polarity to the anode pulse, a positive pulse rather than a negative pulse. 20-Sep-19 04:18 PM So am I even remotely correct in assuming that I can squeeze some more life from those Soviet Gen0 and Gen1 NVG crap by pushing the voltages up? 20-Sep-19 04:18 PM Because the polish unit I tested was rather bad 20-Sep-19 04:19 PM If you mean night vision stuff I doubt it. 20-Sep-19 04:22 PM ok. 20-Sep-19 04:22 PM This was a trick for PMTs used to detect scintillation, they often have a lot of stages and can be pushed a bit, the limit in general use isn't the amplification but the life and current delivery of the last dynode. 20-Sep-19 04:22 PM Because that polish soviet era NVG I sted was CRAP. 20-Sep-19 04:22 PM IIRC NVG's don't have PMT stages. 20-Sep-19 04:24 PM nods. 20-Sep-19 04:36 PM I'll add the only other trick I learned about PMTs, looking at stats you'd think beryliated copper dynodes are crap you have no other choice to use in oil wells when the high temperature means all the good secondary emitters have too high thermionic emission. The high voltages those dynodes need for half decent amplfication also means that the timing on those PMTs is better (on equal basis) than any other dynode. So if time resolution was most important you'd want BeCuO dynodes in a linear focus PMT. My memory of the numbers was that it halved the pulse to pulse jitter. Much less practical info, and probably obsolete now, but I thought that was cool thinking. 20-Sep-19 06:14 PM Dynodynes? 20-Sep-19 06:14 PM Because I was ready to order berryliated copper/beryllium bronze parts from sub contractors. 20-Sep-19 06:14 PM Yea really. 20-Sep-19 06:14 PM Vaporized beryllium. gota love lazers 21-Sep-19 12:40 AM @ali_as what you're thinking of is the photocathode, but the dynodes are just CuBe 21-Sep-19 01:37 AM filing a cube of becu 22-Sep-19 03:34 AM oof 22-Sep-19 03:34 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20190922-111607-Anonnymphe-id3428714-94DD1.jpg 22-Sep-19 03:34 AM Tell me thats not 22-Sep-19 03:34 AM where i think it is 22-Sep-19 03:34 AM yes it is 22-Sep-19 03:34 AM sigh 22-Sep-19 03:34 AM just 22-Sep-19 03:35 AM it is where you think it is and it is what you think it is 22-Sep-19 03:35 AM no 22-Sep-19 03:35 AM Like was this used for general decontamination or... 22-Sep-19 03:35 AM nope 22-Sep-19 03:35 AM way better 22-Sep-19 03:36 AM spicier stuff... 22-Sep-19 03:36 AM this was one of the many attempts to get the rubble of the roof 22-Sep-19 03:36 AM significantly louder sighs 22-Sep-19 03:36 AM Was this thing decontaminated at some point? 22-Sep-19 03:36 AM Not that it would help that much 22-Sep-19 03:38 AM nope 22-Sep-19 03:38 AM oof 22-Sep-19 03:38 AM big oof 22-Sep-19 03:38 AM yep 22-Sep-19 03:38 AM ~500 µSv/h gamma on the inside 22-Sep-19 03:38 AM roundabout 22-Sep-19 03:39 AM There is a highly technical industry recognized way to describe that: 22-Sep-19 03:39 AM lol nope 22-Sep-19 03:39 AM should be waaaay more beta, thanks to the activated Co in the shovels 22-Sep-19 03:40 AM Yeah I was going to say after this much time there has to be a lot more than the original gamma 22-Sep-19 03:41 AM blames it all on this stupid f... series 22-Sep-19 03:41 AM yup 22-Sep-19 03:41 AM I will say there was that one time I was watching a video on the area and though I heard a familiar voice in the back ground. 22-Sep-19 03:43 AM carl? 22-Sep-19 03:43 AM The camera pans and one of my friends is chasing a particle of something with a meter and a small pick digging next to a similar looking piece of equipment... 22-Sep-19 03:43 AM Not carl 22-Sep-19 03:43 AM Wait are you referring to who I was watching or the persons name? 22-Sep-19 03:44 AM carl was just the first person that came to mind whom I'd expect to meet there and recognize their voice 22-Sep-19 03:49 AM Understanable 22-Sep-19 03:49 AM If were talking about the same carl I dont think he has been there 22-Sep-19 03:50 AM willis 22-Sep-19 03:50 AM he has definitely been there 22-Sep-19 03:51 AM There 2 carls im thinking of 22-Sep-19 03:51 AM the only other one that I can think of atm is my neighbour, but I'm having my doubts you're talking about him 23-Sep-19 02:32 AM https://www.ebay.com/itm/133138426496 This looks so cool 23-Sep-19 04:13 AM I was talking to a friend and he reminded me of this source 23-Sep-19 04:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/science-B8129.png 23-Sep-19 04:13 AM I just want everyone to know that this exists and gives off 40 Sv/h at one meter distance 23-Sep-19 04:13 AM the font looks small, let's say you have to get 10 cm close to this to read it 23-Sep-19 04:13 AM that's over 1 Sv/s 23-Sep-19 04:48 AM lol 23-Sep-19 04:48 AM drop & run 23-Sep-19 04:48 AM they dead? 23-Sep-19 04:52 AM it's kinda hard to find a good source on that picture 23-Sep-19 04:52 AM but considering it has no dead pixels I'd say the actual source isn't in there 23-Sep-19 04:52 AM ah ok no insta or twitter account 23-Sep-19 04:52 AM dead pixel as in hot pixel? 23-Sep-19 04:52 AM thought modern cams do a removal 23-Sep-19 04:53 AM dead pixel 23-Sep-19 04:53 AM ok 23-Sep-19 04:53 AM they do, up to a certain extend 23-Sep-19 04:53 AM ok ^^ 23-Sep-19 04:53 AM https://www.youtube.com/watch?v=Uf4Ux4SlyT4 23-Sep-19 04:54 AM hmm 23-Sep-19 04:54 AM an atmospheric e-beam should be easy to make, right? 23-Sep-19 04:54 AM free space particle beam fetish 23-Sep-19 04:54 AM yep 23-Sep-19 04:54 AM just not at 3.0MeV, 50mA 23-Sep-19 04:55 AM i mean a visible 23-Sep-19 04:55 AM for huumans 23-Sep-19 04:55 AM http://www.rapp-instruments.de/diverse/Lenard/lenard.htm 23-Sep-19 04:55 AM i mean i only know this famous cyclotron image 23-Sep-19 04:55 AM nice 23-Sep-19 04:55 AM now videos!! 23-Sep-19 04:57 AM don't have any, sorry ^^ 23-Sep-19 04:59 AM hmmm 23-Sep-19 07:17 AM dumb geiger counter design 23-Sep-19 07:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Fusion360_CW5U5mDybT-C6F38.png 23-Sep-19 07:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Fusion360_4mbaeeth1N-673FA.png 23-Sep-19 07:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Fusion360_1jlQD9v0nL-12EFC.png 23-Sep-19 07:31 AM Too many ports and holes, but I like the overall design 23-Sep-19 07:37 AM :D 23-Sep-19 08:47 AM the electron beam irradiator is sick 23-Sep-19 08:48 AM hell yeah 23-Sep-19 08:50 AM this blue glow and the sick sound 23-Sep-19 08:51 AM angry 60 Hz 23-Sep-19 08:51 AM yep 23-Sep-19 08:51 AM i mean wahhh 23-Sep-19 08:51 AM tha faaa 23-Sep-19 08:51 AM and that's "only" 3MeV with 50mA 23-Sep-19 09:28 AM 50 f-ing mA! 23-Sep-19 10:08 AM yeah of course but i mean ... iffff 23-Sep-19 05:02 PM oh gosh 23-Sep-19 05:02 PM i don't need but kinda want that jomar thing 23-Sep-19 05:02 PM but i already have two 6LiI(Eu) scintillators.. so.. 23-Sep-19 05:33 PM @GigaSquirrel @qualia it's also sold as the TSA detector 23-Sep-19 05:33 PM PRM-something 23-Sep-19 05:33 PM there's two versions - with a plastic scintillator, and with plastic scintillator + neutron detector 23-Sep-19 05:33 PM it's a project box with a chunk of stain-gobain plastic inside 23-Sep-19 05:33 PM now this... 23-Sep-19 05:33 PM https://www.ebay.com/itm/Thermo-Electron-Interceptor-Spectroscopic-Personal-Radiation-Detector-SPRD/223669166274 23-Sep-19 05:33 PM this is a worthy purchase 23-Sep-19 05:53 PM https://www.ebay.com/itm/LUDLUM-12-4-GIEGER-COUNTER-WITH-NEUTRON-BALL/273921143814 remball sans detector 23-Sep-19 05:53 PM c a d m i u m o r b 23-Sep-19 06:12 PM I'm having a lot of trouble finding an affordable microfocus x-ray head :( 23-Sep-19 09:08 PM @Deleted User I want to take a old TEM and use the illumination part of the column as a microfocus head. 23-Sep-19 09:08 PM The problem with the is that the spare parts everyone wants is the high voltage cable and the ceramic insulator 23-Sep-19 09:09 PM You could do that, but you'd probably need to chill the anode and run it in pulse mode 23-Sep-19 09:09 PM There are some alternative guns available for the TEMs that have insane amount of probe current 23-Sep-19 09:09 PM Define insane 23-Sep-19 09:10 PM Pulsed? 23-Sep-19 09:10 PM Very low duty cycle 23-Sep-19 09:11 PM Something on the order amp 23-Sep-19 09:11 PM When turned up all the way 23-Sep-19 09:11 PM Its insanity 23-Sep-19 09:11 PM An amp dumped into a few hundred nm? 23-Sep-19 09:11 PM Of beam current if you measured the packet of electrons 23-Sep-19 09:11 PM that won't melt, that'll straight up sputter 23-Sep-19 09:12 PM Yeah it did 23-Sep-19 09:12 PM You have to turn it down 23-Sep-19 09:12 PM It was cool though from what i hear 23-Sep-19 09:12 PM It almost sounds like an explosive emission gun 23-Sep-19 09:12 PM Photo emission 23-Sep-19 09:12 PM ah 23-Sep-19 09:12 PM I wonder how feasible a DIY microfocus system with a photo emission cathode would be 23-Sep-19 09:12 PM Just a tiny circle, maybe a micron across, blasted with a laser 23-Sep-19 09:12 PM So you have to do less work collimating the beam, just guide it down onto the target and get sharp x-rays 23-Sep-19 09:14 PM You would still need some beam colimaton 23-Sep-19 09:14 PM not as much as for a beam of ~1mm in diameter 23-Sep-19 09:14 PM But maybe you could build the entire gun in the magnetic field 23-Sep-19 09:14 PM You would get a massive amount of current that way 23-Sep-19 09:15 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/SchematicviewofamicrofocusX-raytube-18D0A.png 23-Sep-19 09:15 PM this is how most industrial microfocus sources work 23-Sep-19 09:15 PM If your point source is small enough then a single immersion field guiding the beam right on target might work 23-Sep-19 09:15 PM Yeah that's exactly what the top of a TEM looks like 23-Sep-19 09:16 PM maybe that's why they look like that :P 23-Sep-19 09:16 PM someone decided "what if we just sell 1/10th of a TEM for the price of a TEM" 23-Sep-19 09:16 PM Lol pretty much 23-Sep-19 09:16 PM They probably got the ceramic from the same vendor that FEI does because why would you do anything else 23-Sep-19 09:18 PM did you know that Canon makes x-ray sources 23-Sep-19 09:18 PM No but thats also the least surprising thing ever 23-Sep-19 09:18 PM 4 microns at 10 watts 23-Sep-19 09:18 PM You can tell me any large Japanese company makes anything and I would not be surprised. 23-Sep-19 09:18 PM JEOL, which stands for Japanese Electron Optics Laboratory used to make plastic animal toys in the same factory they made electron microscopes 23-Sep-19 09:19 PM the metal jet x-ray systems are mindblowing 23-Sep-19 09:20 PM Liquid metal ion source stuff? 23-Sep-19 09:20 PM it's basically a TEM head, but the target is a stream of metal 23-Sep-19 09:20 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/MetalJet_isolated_shadow_medium-0FD1D.png 23-Sep-19 09:20 PM Wait the target? 23-Sep-19 09:20 PM Damn 23-Sep-19 09:20 PM yes! 23-Sep-19 09:20 PM can't melt the target if it's already molten 23-Sep-19 09:20 PM We are approaching waters cooled ir lamps for semicondutor stuff 23-Sep-19 09:20 PM as in the inside of the lamp tube is at high vacuum, but also has chilled water running at laminar flow on the inside surface exposed to vacuum 23-Sep-19 09:22 PM the pump must be weeping 23-Sep-19 09:22 PM They just stuck some big turbo pumps on the ends and called it a day 23-Sep-19 09:22 PM A single pulse from the lamp would melt the tube if they didnt 23-Sep-19 09:23 PM I kinda want to stick to sealed x-ray tubes for my microtomograph 23-Sep-19 09:23 PM There's a guy that is still promising to send me an Yxlon FXE-160.48 system, but he's saying the company is having a hard time scrapping it because they found some radioactive contamination somewhere, so I'm guessing at this point I won't ever get it 23-Sep-19 09:24 PM I forget what exactly its for, but they needed some insane temperature rise time on the surface of the entire wafer 23-Sep-19 09:24 PM rip 23-Sep-19 09:24 PM Radioactive contamination is a funny thing when it comes to trying to get surplus hardware 23-Sep-19 09:25 PM That's the thing - why of all places would radioactive contamination be on an x-ray system? 23-Sep-19 09:25 PM I mean 23-Sep-19 09:25 PM If you want to image something radioactive? 23-Sep-19 09:25 PM the guy said something about radium paint 23-Sep-19 09:25 PM so either he doesn't want to give it to me and he realized he's offering to give away a nice car's worth of equipment, or he's trying to get rid of it and can't 23-Sep-19 09:26 PM Iv seen people do x ray spectroscopy on ludicrously hot samples 23-Sep-19 09:26 PM Like hot enough that it destroyed the microscope after they ran it 23-Sep-19 09:27 PM that seems a bit dangerous 23-Sep-19 09:27 PM XRF on an already radioactive sample? 23-Sep-19 09:27 PM Energy dispersive 23-Sep-19 09:27 PM ah 23-Sep-19 09:27 PM Thus the use of an electron microscope 23-Sep-19 09:27 PM They put the entire unit into glove box 23-Sep-19 09:28 PM oh wait, they put it into a SEM? 23-Sep-19 09:28 PM oh no... :( 23-Sep-19 09:28 PM Yeah 23-Sep-19 09:28 PM These people were crazy 23-Sep-19 09:28 PM that's an expensive consumable 23-Sep-19 09:28 PM And by glove box i mean hot cell 23-Sep-19 09:29 PM it must have been worth burning $100k+ on a single examination 23-Sep-19 09:29 PM Im pretty sure they had a bulk purchase of table top microscopes 23-Sep-19 09:29 PM Which for the stuff they were doing it on was not a massive expense all things considered 23-Sep-19 09:30 PM that is crazy 23-Sep-19 09:30 PM Yeah 23-Sep-19 09:30 PM As i said insane 23-Sep-19 09:30 PM They didnt destory the scope every time 23-Sep-19 09:30 PM This was just a particularly hot sample 23-Sep-19 09:30 PM often is still too much 23-Sep-19 09:31 PM I mean 23-Sep-19 09:31 PM Have you seen NIF? 23-Sep-19 09:31 PM Or even better z machine? 23-Sep-19 09:32 PM On pictures 23-Sep-19 09:32 PM Z machine gets a core swap every day 23-Sep-19 09:32 PM and by core swap I mean the entire inside of the inner vessel, not just the pellet 23-Sep-19 09:32 PM Probably takes a team of 10-30 to do that 23-Sep-19 09:32 PM Average salary of 100k each 23-Sep-19 09:32 PM Lets say 200 shots per year in a good year 23-Sep-19 09:32 PM that's up to 150k per shot just in person time 23-Sep-19 09:34 PM That definitely puts the costs into perspective 23-Sep-19 09:34 PM But it's still painful to think that somewhere, some place, has SEMs as a line item consumable 23-Sep-19 09:35 PM But in reality those type of people are probably doing better than 100k, and with benefits package... 23-Sep-19 09:35 PM looks like I found the core 23-Sep-19 09:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/z-machine-2-DBE7D.png 23-Sep-19 09:35 PM yup 23-Sep-19 09:35 PM The only reason that thing is shiny is because it's brand new, and its a single use 23-Sep-19 09:35 PM Not pictured is some of the interconnection rings 23-Sep-19 09:36 PM Up to 200 terawatts during a pulse 23-Sep-19 09:36 PM Yeah 23-Sep-19 09:36 PM You try and grab the data before the instrumentation is vaporized. 23-Sep-19 09:37 PM I really like this sign 23-Sep-19 09:37 PM https://i.spirit.re/aBa81.png 23-Sep-19 09:37 PM A very polite way of saying "if you're inside when it fires, you're out" 23-Sep-19 09:39 PM Lol yeah 23-Sep-19 09:39 PM There's a video of the firing room somewhere 23-Sep-19 09:40 PM I'm watching it 23-Sep-19 09:40 PM The whole facility is filled with the "pthheeew" of cryopumps :P 23-Sep-19 09:40 PM Lol national labs seem to really like big chambers 23-Sep-19 09:41 PM I'm aiming for a much lower current :P 23-Sep-19 09:41 PM If I find a sponsor, I'll probably get this 23-Sep-19 09:41 PM https://www.ebay.com/itm/Hamamatsu-x-ray-tube-L9631/383129380125 23-Sep-19 09:41 PM It's not the best, variable 18-80um focus 23-Sep-19 09:41 PM but the best is basically unavailable, or sold without controllers in "as-is" condition 23-Sep-19 09:41 PM :( 23-Sep-19 09:43 PM Hey the fact that its pretty self contained 23-Sep-19 09:43 PM Looks like all the optics drivers are internal 23-Sep-19 09:43 PM all hamamatsu systems are 23-Sep-19 09:43 PM and you can dump roms to figure out rs coms 23-Sep-19 09:43 PM this is a much much better tube 23-Sep-19 09:43 PM https://www.ebay.com/itm/HAMAMATSU-PHOTONICS-L7902-X-RAY-TUBE-as-photo-sn-Promotion-Untest-AS-IS/173863565459 23-Sep-19 09:43 PM lower current, lower power, but a constant 5 micron focus 23-Sep-19 09:43 PM Reversing optics from scratch is a massive pita 23-Sep-19 09:43 PM HOWEVER, it's a complete black box 23-Sep-19 09:43 PM the controller is available, also, but it's another $1k+ 23-Sep-19 09:43 PM and no guarantee it would ever work, despite being pin-compatible AFAIK 23-Sep-19 09:43 PM https://www.ebay.com/itm/HAMAMATSU-C8033-01-Phoenix-X-RAY-CONTROL-UNIT-as-photo-sn-0121-Promotion/173863512799 23-Sep-19 09:43 PM these two are supposed to go together, in theory. 23-Sep-19 09:43 PM but there's no way in the world I can afford that on my own 23-Sep-19 09:47 PM Those do look like fun 23-Sep-19 09:47 PM I have a sensor worthy of these 23-Sep-19 09:47 PM thanks to a very generous friend 23-Sep-19 09:55 PM I think @niklas was looking into microfocuse x ray a while back 23-Sep-19 09:56 PM He and @ janhenrik succeeded in reverse-engineering a Glenbrook head 23-Sep-19 09:56 PM There's one on eBay for a very sad price in very sad condition 23-Sep-19 09:57 PM Oh nice I didnt see that 23-Sep-19 09:58 PM https://twitter.com/fauthniklas/status/1123745053032292357 23-Sep-19 10:00 PM I like that he is still using the dental software 23-Sep-19 10:01 PM the sensors are a pain to talk to, the only ones that have been reverse-engineered were the Gendex GXS-700/Dexis Platinum sensors 23-Sep-19 10:01 PM By John McMaster 23-Sep-19 10:01 PM Yeah that was a cool project 23-Sep-19 10:01 PM I have one of those as well, but it's pretty dead 23-Sep-19 10:01 PM I want to get into x ray stuff at some point but its not going to happen until I get a new shop 23-Sep-19 10:01 PM Im going to have 4 SEMs cramed into mine soon 23-Sep-19 10:02 PM Donate to my crazy projects and I'll x-ray everything for you :P 23-Sep-19 10:02 PM There will be about a 20 inches around 3 sides of each system 23-Sep-19 10:02 PM that's enough to fit tiny desks into 23-Sep-19 10:03 PM I mean I already have 20 feet of bench top 23-Sep-19 10:03 PM I should really get rid of one of the benches 23-Sep-19 10:04 PM Makes room for one more SEM 23-Sep-19 10:04 PM They are 36"s deep 23-Sep-19 10:04 PM Not even 23-Sep-19 10:04 PM It make room for the power supply for one more SEM 23-Sep-19 10:04 PM This is why you need to get into benchtop SEMs 23-Sep-19 10:04 PM you've already had experience with one 23-Sep-19 10:05 PM Theres a lot of stuff I dont talk about on here 23-Sep-19 10:05 PM Benchtop electron microscopes are one... 23-Sep-19 10:06 PM I'm sure that's an interesting topic 23-Sep-19 10:06 PM Very 23-Sep-19 10:06 PM There's a lot of tricks to get a microscope that small to work 23-Sep-19 10:07 PM I'm going to get to x-raying at some point 23-Sep-19 10:07 PM I guess I could offer up my collection of weird soviet(and some not so soviet) tubes up for trade, to get one good microfocus source 23-Sep-19 10:08 PM Dont look at me I dont have one either 23-Sep-19 10:08 PM Hm 23-Sep-19 10:08 PM I have a column that can hit 40 kv 23-Sep-19 10:08 PM I could put a plate in the SEM 23-Sep-19 10:08 PM then a sensor below that in the chamber 23-Sep-19 10:09 PM I'd need at least 100 for doing the most interesting and beautiful stuff 23-Sep-19 10:09 PM Yeah 23-Sep-19 10:09 PM But 40 is not bad 23-Sep-19 10:09 PM enough for maybe a 4-layer board 23-Sep-19 10:09 PM Or basic die work 23-Sep-19 10:09 PM with enough exposure time 23-Sep-19 10:10 PM x-rays aren't very useful for dies though 23-Sep-19 10:11 PM Bond wire stuff 23-Sep-19 10:11 PM And for basic fib targeting 23-Sep-19 10:11 PM https://i.spirit.re/OldD9.png 23-Sep-19 10:11 PM I believe this was done with a head around 5-10 microns, not sure though 23-Sep-19 10:11 PM This is sort of my goal, but if I can go even higher mag, I definitely will 23-Sep-19 10:11 PM a 5 micron head can resolve(just about, blurry mess) around 500nm on a good day, but only in a 2D projection 23-Sep-19 10:16 PM Im going to warn you that resolution is adictive 23-Sep-19 10:16 PM That is a sacrifice I'm willing to make 23-Sep-19 10:16 PM But at that point, the only thing better is a nanofocus tube, beyond state of the art 23-Sep-19 10:16 PM Which is very much unlike SEM stuff, where you can always buy a better one 23-Sep-19 10:20 PM Well its kinda like the leap from thermionic to field emission 23-Sep-19 10:20 PM it's more like a leap from field emission to that hitachi building-sized tem 23-Sep-19 10:20 PM thermionic to feg is going from a peasantly dental x-ray tube to a microfocus 23-Sep-19 10:20 PM Oh their 3 MEV microscope? 23-Sep-19 10:21 PM yeah 23-Sep-19 10:21 PM That thing kinda sucks 23-Sep-19 10:21 PM does it? 23-Sep-19 10:21 PM It's got voltage sure 23-Sep-19 10:21 PM But it sure doesnt have the resolution records 23-Sep-19 10:21 PM Those are held by the state of the art corrected probe microscopes 23-Sep-19 10:21 PM well, going from micro to nanofocus is going from cfeg to the highest resolution scope in the world 23-Sep-19 10:22 PM Which have like an order of magnitude on that thing. 23-Sep-19 10:22 PM you can, but it's very expensive and you lose a bunch of functionality 23-Sep-19 10:22 PM (voltage, current) 23-Sep-19 10:22 PM microfocus heads are at the stage where they have enough voltage to plow through a jet turbine blade but still resolve microfractures 23-Sep-19 10:25 PM With more voltage its easier to get more resolution 23-Sep-19 10:25 PM Not just because of wavelength stuff 23-Sep-19 10:25 PM x-ray? 23-Sep-19 10:25 PM On the elctron side 23-Sep-19 10:25 PM Getting the spot size smaller 23-Sep-19 10:26 PM with x-rays voltage only really makes things harder 23-Sep-19 10:26 PM both to focus the electrons and to shield from the resulting emissions 23-Sep-19 10:26 PM Well yeah contrast drops but the diffraction stuff gets better. 23-Sep-19 10:26 PM it's not even that the contrast drops 23-Sep-19 10:26 PM at a certain point things just go transparent to any reasonable detector without a million bits of dynamic range 23-Sep-19 10:27 PM Isint that contrast? 23-Sep-19 10:27 PM you can't blast a PCB with 160kV, it'll just be a field of very faint solder spots 23-Sep-19 10:27 PM it's contrast, but you also blow the image out completely at some point 24-Sep-19 01:43 PM Pinned a message. 24-Sep-19 01:43 PM i also love that sign 24-Sep-19 01:43 PM "This kills the technician" 24-Sep-19 01:56 PM heh 24-Sep-19 02:00 PM i have a 'this thing produces ionizing radiation when energized' sign that was briefly installed in front of my Apparatus, when that was a thing it was capable of doing 24-Sep-19 02:00 PM i wonder if anyone's done any, like, neutron activation studies of fusor hobbyists' workspaces 24-Sep-19 02:00 PM (i suspect it's pretty minuscule) 24-Sep-19 02:05 PM most of the materials are organics that are barely activatable 24-Sep-19 02:07 PM my fusor is physically supported by a 55 gallon drum full of paraffin wax with tantalum capacitor sprinkles 24-Sep-19 02:07 PM for aesthetic support 24-Sep-19 02:13 PM gotta keep my ZnS ceiling stars shimmering somehow 24-Sep-19 02:13 PM in semi-unrelated news, i've got a Ludlum 177 on the way 24-Sep-19 02:17 PM I'm bored of these old analog counters at this point 24-Sep-19 02:17 PM almost passed it up 'cos it's just got some victoreen GM probe, but... it comes with a NIST-calibrated 137Cs check source 24-Sep-19 02:17 PM idk boring is nice when reliability and repairability is called for, but, fair 24-Sep-19 02:17 PM NIST-calibrated, or NIST-traceable? 24-Sep-19 02:18 PM dunno 24-Sep-19 02:18 PM it may not be that the check source is but that the meter was originally calibrated to NIST's specs 24-Sep-19 02:18 PM likely the latter, which isn't very useful 24-Sep-19 02:18 PM i do not know the difference, in fairness 24-Sep-19 02:18 PM calibration lapses fast 24-Sep-19 02:19 PM mostly i just wanted the 137Cs check source 24-Sep-19 02:19 PM you know you can just buy them brand new, right? 24-Sep-19 02:19 PM yeah 24-Sep-19 02:19 PM i almost did 24-Sep-19 02:20 PM http://unitednuclear.com/index.php?main_page=product_info&cPath=2_5&products_id=819 24-Sep-19 02:21 PM yeah i got a quote from spectrum techniques a bit ago, they were very similar in price 24-Sep-19 02:21 PM I have a slightly dead Atomtex AT-1123 for sale if you want it 24-Sep-19 02:21 PM what's dead about it? 24-Sep-19 02:21 PM it works and sees radiation, but after a bit of warmup the compensation circuit decides it's now touring a neutron star 24-Sep-19 02:22 PM snrk 24-Sep-19 02:22 PM I don't need it, since I have a few other meters 24-Sep-19 02:22 PM but I wouldn't mind trading it for money or something like an Eberline E600 24-Sep-19 02:28 PM i'd be a little worried about throwing $$$($?) at a widget that i'm not sure if i could even repair 24-Sep-19 02:28 PM my electronics skills are not quite at the point where i'd trust myself repairing what looks like a very modern device 24-Sep-19 02:28 PM the circuit is very discrete and analogish 24-Sep-19 02:28 PM the design is oooooooold 24-Sep-19 02:28 PM mine was made in 2003 24-Sep-19 02:28 PM fair 24-Sep-19 02:28 PM the pulsed performance is appealing 24-Sep-19 02:28 PM most of my hardware is from 1960-1990 >.> 24-Sep-19 02:29 PM it's got a hamamatsu PMT and some plastic scintillator with a funky compensation LED dingus 24-Sep-19 02:29 PM i think the only digital counter i have is a GQ GMC500+ 24-Sep-19 02:29 PM and i sat on it once and goofed up the LCD 24-Sep-19 02:29 PM this is definitely a step up 24-Sep-19 02:29 PM if repaired 24-Sep-19 02:29 PM yeah lol 24-Sep-19 02:30 PM I just want to buy a microfocus x-ray head :( 24-Sep-19 02:30 PM i have a microfocus x-ray tube but the spot size is i think bigger than you'd like 24-Sep-19 02:30 PM 50 microns iirc 24-Sep-19 02:30 PM 50 is barely micro :P 24-Sep-19 02:30 PM I'm pining after a 5 micron tube 24-Sep-19 02:30 PM also it needs.. power.. filament.. oil cooling.. 24-Sep-19 02:30 PM nod 24-Sep-19 02:31 PM yep 24-Sep-19 02:31 PM there's one on eBay right now and there's a bidding war 24-Sep-19 02:31 PM which I'm hoping to win 24-Sep-19 02:31 PM (snipe) 24-Sep-19 02:32 PM i believe in you ❇ 24-Sep-19 02:32 PM fitting emotes 24-Sep-19 02:33 PM good luck! 24-Sep-19 03:04 PM I'm going to drop this offer here, maybe that can help me a bit 24-Sep-19 03:13 PM I have a collection of items: 1 - A used, slightly dead(see above) Atomtex AT-1123 compensated, pulse-capable scintillation meter 2 - A brand new(not in box, but never powered up!) CEI OX-70/g4 X-ray tube(75kV, 100W/500W pulse, 400um focus) 3 - A used soviet BS6 tube - 100kV 2W, electrostatically+magnetically focused, down to 20um, 100um with electrostatic only). I have the datasheet and focus specifications for it, as well as its passport and characteristics. 4 - Two soviet BS10 tubes with a focusing magnet - almost identical to the BS6, but I don't have any info for these. They're smaller, so lower voltage, but the filament and focus voltages are compatible. I've powered it up, and it does produce an image similar to the BS6, but a bit blurrier. Might be tweakable with focusing. The focus magnet from the BS10 tubes is the same as the magnet for BS6 tubes, swappable. I'm open to selling any of these, or trading a few of these with extra payment from me for a working microfocus x-ray head. 24-Sep-19 03:14 PM may want to copy that into #swap-meet too if you've not done so already 24-Sep-19 03:14 PM Will do 24-Sep-19 04:56 PM also, was reading the manual for a lock-in amplifier, saw this thought-provoking warning about unterminated photomultiplier outputs charging up the cable connected to it to instrument-damaging voltages.. kinda neat 24-Sep-19 04:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1569368851_20190924-160931-30C9A.png 24-Sep-19 04:58 PM something you generally don't think of 24-Sep-19 05:02 PM "oh, so that's what they mean by "current pulse"..." 24-Sep-19 05:23 PM Aaaaaaand I lost out on that x-ray head. It's got 5 days left and it's already at $1525. The bidding war goes on. 24-Sep-19 05:23 PM I'll have to try finding another. 24-Sep-19 05:30 PM rip 27-Sep-19 07:18 AM hi 27-Sep-19 07:18 AM Heyo 27-Sep-19 07:18 AM what's a good source for shield bricks? ^^ 27-Sep-19 07:19 AM know someone in decon 27-Sep-19 07:19 AM https://www.radiationproducts.com/lead-brick 27-Sep-19 07:19 AM those bricks get thrown away daily 27-Sep-19 07:19 AM hehe 27-Sep-19 07:19 AM i know you 27-Sep-19 07:19 AM kinda 27-Sep-19 07:19 AM I don't work in decon anymore :/ 27-Sep-19 07:20 AM ok but maybe you know someone who knows 27-Sep-19 07:20 AM i mean, what's the alternative? 27-Sep-19 07:20 AM ok distance and doing less radiation i guess 27-Sep-19 07:20 AM this Electron Beam Irradiator video made me think 27-Sep-19 07:21 AM if you're only after shielding concrete might be the cheapest option 27-Sep-19 07:21 AM it just isn't as dense 27-Sep-19 07:22 AM yep 27-Sep-19 07:22 AM but not like 2-3€per kg, which is a huge plus 27-Sep-19 07:23 AM i mean if i want a relatively high power x-ray source, one simple way of building one would be a betatron, right? 27-Sep-19 07:23 AM like http://lampes-et-tubes.info/xr/xr088.php?l=e 27-Sep-19 07:23 AM or http://lampes-et-tubes.info/xr/xr033.php?l=e 27-Sep-19 07:23 AM i know, such tubes are used in modern x-ray sources 27-Sep-19 07:23 AM https://www.jme.co.uk/products/Betatron-Portable-Xray/betatron-range.html 27-Sep-19 07:25 AM oh wow I didn't know they existed like that 27-Sep-19 07:25 AM they're awesome 27-Sep-19 07:25 AM https://www.jme.co.uk/products/Betatron-Portable-Xray/betatron-9mev.html 27-Sep-19 07:25 AM how nasty 27-Sep-19 07:26 AM wow 27-Sep-19 07:26 AM now I want one 27-Sep-19 07:26 AM damn you 27-Sep-19 07:27 AM "> 20 Roentgen / minute" :> 27-Sep-19 07:27 AM now shielding that much energy is pretty hard 27-Sep-19 07:27 AM as you won't just absorb the photons but get particle showers in your shield 27-Sep-19 07:28 AM @1 m distance 27-Sep-19 07:28 AM yeah 27-Sep-19 07:28 AM it seems to be a every day tool for civil engineering 27-Sep-19 07:28 AM but yeah, they also use radioactive sources for similar jobs ... %) 27-Sep-19 07:28 AM but that 27-Sep-19 07:28 AM switch on all dead switch off 27-Sep-19 07:28 AM right? 27-Sep-19 07:30 AM ~100 Sv/h is a usual value for those gamma sources 27-Sep-19 07:31 AM 20R/m is plenty 27-Sep-19 07:31 AM per minute i mean waaaat 27-Sep-19 07:32 AM as is 9 MeV 27-Sep-19 07:32 AM yes 27-Sep-19 07:32 AM you could use it as a photoneutron source 27-Sep-19 07:32 AM oh hum, interesting idea yeah 27-Sep-19 07:32 AM but if those tools are used on a daily base @ more or less normal construction sites 27-Sep-19 07:32 AM there should be some 'used' ones 27-Sep-19 07:35 AM was thinking the same 27-Sep-19 07:35 AM ^^ 27-Sep-19 07:35 AM but I've never seen one 27-Sep-19 07:35 AM or heard of them 27-Sep-19 07:36 AM and then ... a betatron seems to be a pretty easy system 27-Sep-19 07:36 AM besides that it's not exactly a good point source, right? since it would be very hard to focus the beam on a small sub mm spot before hitting the target? 27-Sep-19 07:38 AM I have no idea tbh 27-Sep-19 07:38 AM michio kaku built one as a teenager, but there's no information aviable on it 27-Sep-19 07:38 AM oh you mean as a point x-ray source 27-Sep-19 07:38 AM well microfocus will be hard at some MeV 27-Sep-19 07:38 AM but in general it should not be worse than some dental x-ray stuff 27-Sep-19 07:40 AM hmm 27-Sep-19 07:40 AM a > 10MeV microfocus source would be bad ass, right? 27-Sep-19 07:40 AM i know, how to cool the target 27-Sep-19 07:40 AM another idea: couple the e-beam out and pass it through an undulator magnet configuration 27-Sep-19 07:40 AM voila, FEL? 27-Sep-19 07:42 AM but cooling the target doesn't depend on the voltage, only power 27-Sep-19 07:42 AM yes 27-Sep-19 07:42 AM you could reduce the current, that's right 27-Sep-19 07:42 AM but ideal would be high power and small source size 27-Sep-19 07:42 AM (of course) 27-Sep-19 07:42 AM so that's why an FEL comes into mind, right? 27-Sep-19 07:42 AM i mean srsly 27-Sep-19 07:43 AM but is an FEL really close to a point source? 27-Sep-19 07:43 AM how precise is such an undulator manufactured? 27-Sep-19 07:43 AM tbh the "L" part implies a rather parallel beam 27-Sep-19 07:43 AM no idea ^^ 27-Sep-19 07:43 AM ask desy 27-Sep-19 07:47 AM wait, but it's coherent, so you can manage to make it point source like 27-Sep-19 07:47 AM like with visual lasers 27-Sep-19 07:47 AM but with much more ehh complex optics of course 27-Sep-19 07:49 AM I wanna see those optics 27-Sep-19 07:50 AM ok, forget the xray FEL idea, you would need like 10 GeV electrons 27-Sep-19 07:56 AM oh 27-Sep-19 07:56 AM whoops 27-Sep-19 07:56 AM but you can generate such electrons on a table top with wakefield accelerators 27-Sep-19 07:57 AM once we get those to work 27-Sep-19 07:57 AM within plasma generated by short highpower laser pulses 27-Sep-19 07:57 AM so for short time high power FEL stuff it's possible, but completely different approach 27-Sep-19 07:57 AM http://www.tubecollection.de/ura/images_100/Betatron_Siemens_P1060028.jpg 27-Sep-19 08:05 AM I wanna see the magnet for this 27-Sep-19 08:26 AM http://www.svetlana-x-ray.ru/production-list-eng.html?cid=19 27-Sep-19 08:29 AM also werden die sogar noch hergestellt? oder zumindest lagerware abverkauft, weil altert ja eher kaum 27-Sep-19 08:31 AM according to some 4hv thread those are the tubes in the x-ray sources you posted 27-Sep-19 08:31 AM https://4hv.org/e107_plugins/forum/forum_viewtopic.php?98356.0 27-Sep-19 08:36 AM with links to fusor.net ^^ 27-Sep-19 08:36 AM first search on fusor.net i did was about "cyclotron" 27-Sep-19 08:36 AM found threads about "EXEDA" 27-Sep-19 08:38 AM @Applied_Ion I didn't look in the fusor forum for quite a while, have you finally posted something on exeda? 27-Sep-19 08:43 AM No, I stopped posting there. Haven't even looked in a while lol. I'll probably post something on twitter after I discuss it at the conference in October, at this point I might not get to doing it for a long time. Thruster stuff has way overextended my resources in both time and money. The design is done lol, can't afford to get it machined yet lol. Still need to set up instrumentation to measure beam and other stuff too. 27-Sep-19 08:43 AM fair enough 27-Sep-19 08:43 AM thanks for the update ^^ 27-Sep-19 08:44 AM Np lol. Sad part is its such a stupid simple system, building it is trivial 27-Sep-19 08:44 AM And i can fire it in theory down to 25kv, so getting some beam isn't really an issue either 27-Sep-19 08:46 AM send me the plans and I'll machine and test it :3 27-Sep-19 08:48 AM i came there by accident 27-Sep-19 08:48 AM Lol you would need an insulator stack in addition to the main accelerator. I was planning on designing one to fit standard conflat hardware made from aluminum and acrylic, but I haven't had time yet. 27-Sep-19 08:48 AM i guess it was the first time ever that i read there 27-Sep-19 08:48 AM @N00N welcome 27-Sep-19 08:48 AM @Applied_Ion well, don't rush it or some mistakes might happen 27-Sep-19 08:48 AM best of luck with your project! 27-Sep-19 08:50 AM Thanks lol, this new thruster phase has devolved into an utter s*** show. At least with the accelerator I can brute force it to work 27-Sep-19 08:51 AM I guess my xmas holiday project will be a doing first steps in offline ISOL 27-Sep-19 08:51 AM first steps in the sense of rigging up 27-Sep-19 08:51 AM "high power xray" stuff is still to scary for me 27-Sep-19 08:51 AM "oh dang, i forgot to switch it off ... meh okay, now i've to tell everyone that i'm gonna die within the holidays" 27-Sep-19 08:55 AM xD 27-Sep-19 08:55 AM so you're saying not everyone in your house is wearing a dosimeter all the time? 27-Sep-19 08:56 AM you mean "oh, look, i guess i know who dies the day after tomorrow :)" 27-Sep-19 08:56 AM with a consicutively family love kiss on the forehead 27-Sep-19 08:57 AM that's the spirit 27-Sep-19 08:57 AM high dose rate stuff can be done safely 27-Sep-19 08:57 AM just need to explain your parents why you need 10 tonnes of concrete in the basement 27-Sep-19 09:06 AM I need 30 27-Sep-19 09:06 AM 27-Sep-19 09:07 AM but on the wrong side of the room 27-Sep-19 09:07 AM you didn't realize yet that it doesn't matter if the radiation goes into the ground 27-Sep-19 09:07 AM Depends...I might make a hobbit hole underneath and put a reactor there. 27-Sep-19 09:07 AM Hah! 02-Oct-19 12:40 AM https://youtu.be/kGERXzl84sk 02-Oct-19 12:40 AM I wonder if I should make a full video out of this 02-Oct-19 12:40 AM With a small script 02-Oct-19 12:40 AM The elusive Bicron G1LE(low energy, thin window and thin scintillator) makes for additional effect :) 02-Oct-19 09:43 AM wow, that's an angry little lens 02-Oct-19 09:43 AM what's the model/specs of it? kinda curious 02-Oct-19 10:17 AM It's the Pentax SMC Takumar 50mm f/1.4 02-Oct-19 10:17 AM One of the best vintage lenses, one of the sharpest and widest too 02-Oct-19 10:17 AM @qualia 02-Oct-19 10:17 AM I bought it with the intention of actually filming with it, because who wouldn't 02-Oct-19 11:30 AM oh nice 02-Oct-19 11:30 AM yeah for sure 11-Oct-19 11:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-26B4A.png 11-Oct-19 12:39 PM stand here, don't move 11-Oct-19 12:40 PM ...or you'll get cancer? 11-Oct-19 01:24 PM I mean, mumbles ALARA mumble mumble.. 11-Oct-19 01:25 PM don't move or you'll get in trouble with the radiation safety officer! 18-Oct-19 10:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/EFcWB0TUEAARxOz-8F80E.png 18-Oct-19 11:40 AM Ugh I saw that lmao 18-Oct-19 11:41 AM Honk! 18-Oct-19 11:41 AM hehe 18-Oct-19 11:41 AM selber! 24-Oct-19 10:37 AM Today's thrift store find 24-Oct-19 10:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191024_133018-CCBCE.jpg 24-Oct-19 10:43 AM heh, noice 24-Oct-19 01:22 PM Sadly it looks like they're all the newer style, Blue read 21cpm, green 16, orange 22, purple 18, smaller purple 18, and my older plate not in this picture was 2100 24-Oct-19 01:24 PM is that minus background? that's quite low 24-Oct-19 01:24 PM nice plate set, in any event 24-Oct-19 01:30 PM That's with background, so yeah, zero reading on the new plates I got today :P 24-Oct-19 01:30 PM But the one I got a while back still makes the counter sing 24-Oct-19 01:30 PM At least I'm only out $3 24-Oct-19 01:38 PM lol, I was going to take a picture comparing the markings on them and I forgot my one that is actually radioactive doesn't have any markings at all, but I didn't notice before that it looks almost like metallic paint 24-Oct-19 01:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191024_163520-8525B.jpg 24-Oct-19 01:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191024_163529-A5B80.jpg 24-Oct-19 01:38 PM There's a notable color difference 24-Oct-19 01:38 PM Looks like I can't upload a picture showing the sparkling effect, seems like jpg artificating removes it 24-Oct-19 01:38 PM oh, it's actually visible in the first photo 24-Oct-19 01:38 PM looks almost like the artifacting of radiation on a camera sensor but it's visible with the human eye as well 27-Oct-19 09:25 AM Oo 27-Oct-19 09:25 AM ah ok you mean its not radioactive 27-Oct-19 09:25 AM thought you can see "hot pixels" 27-Oct-19 10:38 AM A quick reference for fiestaware colors 27-Oct-19 10:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/u_chems1-B1801.png 27-Oct-19 10:38 AM These are uranium salts 27-Oct-19 10:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/uraniumcolors-09F8A.png 27-Oct-19 10:38 AM UO3 is what was used in fiestaware 27-Oct-19 10:38 AM Sometimes UO2 27-Oct-19 10:38 AM The difference is as follows 27-Oct-19 10:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/220px-Uranium_Trioxides-6732D.png 27-Oct-19 10:47 AM https://www.varadis.com/products/ 27-Oct-19 10:47 AM These radiation sensitive FETs are pretty neat, affordable too 27-Oct-19 10:47 AM Automatically integrates the dose absorbed and quite easy to read out 27-Oct-19 10:47 AM The reader's a rip-off though 27-Oct-19 10:53 AM For doses between 1 cGy (1 rad) and 1 kGy (100 krad) 27-Oct-19 10:54 AM Yeah, not something you wear on your body, not this particular type, but it can go lower 27-Oct-19 10:54 AM For doses between "hospital for 4 months" and "boiling away" 27-Oct-19 10:54 AM I suppose it could be useful for empirically calculating DIY synchrotron dose rates 27-Oct-19 10:57 AM You can grow the gate oxide real thick to improve sensitivity 27-Oct-19 10:57 AM Still single-use 27-Oct-19 10:57 AM I'm likely going to get one of these for a beam loss monitor at an electron LINAC 27-Oct-19 10:57 AM That would work 27-Oct-19 10:58 AM In combination with coincidence PIN diodes and potentially scintillating optical fibers 27-Oct-19 10:58 AM The FETs are nice in that it's a real time dose rate monitor that's solid-state, makes them easy to replace, calibrate and maintain 27-Oct-19 09:19 PM WOoo, I'm getting a free x-ray tube as a gift! 27-Oct-19 09:19 PM A whopping 20mW and a focal spot between 1700-1800nm 27-Oct-19 09:19 PM And an insane deadly voltage of... 15kV. Max. 27-Oct-19 09:19 PM I'll make a tiny x-ray microscope for thin objects using it. 27-Oct-19 09:19 PM CCFL inverter, maybe two or three stages of multiplier, in a nice 3D printed housing 27-Oct-19 09:56 PM that is cute, have any photos? 27-Oct-19 10:03 PM from the person sending it 27-Oct-19 10:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/OpBrY_k4Yso-552ED.png 27-Oct-19 10:09 PM It is cute haha 27-Oct-19 10:09 PM I wonder if you could get any useful amount of xrays out of abusing just a standard rectifier vacuum tube for that sort of project 27-Oct-19 10:12 PM you can 27-Oct-19 10:12 PM much more than this even probably 27-Oct-19 10:12 PM but this tube has a 1700nm(!!!) focal spot 27-Oct-19 10:12 PM you can x-ray living cells at this point 27-Oct-19 10:12 PM live 27-Oct-19 10:15 PM glossed over that bit of info i guess, that is very cool 27-Oct-19 10:15 PM I'd need to build an ultra high sensitivity x-ray sensors 27-Oct-19 10:15 PM maybe.. sputter(?) some gadox or CsI:Tl onto a totally bare CMOS sensor 27-Oct-19 10:16 PM would one of the dental xray sensors work? 27-Oct-19 10:16 PM might be easier to get a test setup going with that route than coating a cmos 27-Oct-19 10:16 PM if you strip them bare, maaaaaaybe 27-Oct-19 10:16 PM I have one, it's mostly dead 27-Oct-19 10:16 PM but this(at 15kV max energy and only 20mW INPUT power) wouldn't need the protection and light loss of a fiber optic plate 27-Oct-19 10:16 PM so I think I'd just get an older large CMOS or even CCD sensor, chill it to -20C or something 27-Oct-19 10:16 PM and coat it with a scintillator directly 30-Oct-19 02:01 PM Oh cool @Deleted User you found a BS7. 30-Oct-19 02:01 PM An acquaintance did! 30-Oct-19 02:01 PM He manufactures spectrometers and scintillator meters, found it in his storage, offered to send it to me since we talked about it 30-Oct-19 02:01 PM Congrats, I wish I'd bought one or two when sovtube had them. 30-Oct-19 02:02 PM I wonder if my sensor will see it at all 30-Oct-19 02:02 PM 20mW of input power, 1-5% of that is x-rays 30-Oct-19 02:02 PM W has 2 peaks under 15kv I think. Most of the energy will be quite low. 30-Oct-19 02:02 PM 1 to 5% sounds high as an estimate to me. 30-Oct-19 02:03 PM 1-5% is usually the x-ray output conversion 30-Oct-19 02:47 PM I'm looking at the rule of thumb on http://www.sprawls.org/ppmi2/XRAYPRO/#EFFICIENCY and it suggests around 0.1% which is closer to what I thought. Higher voltage tubes seem to have much higher efficiency. 30-Oct-19 02:47 PM It suggests 0.31 for a W tube at 40kv and I think I've just read a lit value of 0.39% at 40kv. 30-Oct-19 02:53 PM so 20 microwatt x-ray output 30-Oct-19 02:53 PM that's definitely going to need a direct conversion sensor 30-Oct-19 02:53 PM or maybe even an image intensifier with a direct conversion coating 01-Nov-19 03:17 PM https://www.youtube.com/watch?v=5YBXJSgbtS0 01-Nov-19 03:17 PM How a 35 000 Ci Sr-90 source was recovered in Lia, Georgia, in 2001-2. 01-Nov-19 03:17 PM The video first shows training, then actual recovery. 01-Nov-19 03:17 PM This is a documentary video from IAEA, and if you're even a little bit squeamish, I highly recommend you not read the report linked in the description. 01-Nov-19 03:19 PM Tere's a very good report on that 01-Nov-19 03:19 PM See above :P 01-Nov-19 03:19 PM https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1660web-81061875.pdf VERY NSFL 01-Nov-19 03:19 PM yep 01-Nov-19 03:19 PM very very nsfl 01-Nov-19 03:19 PM people suffered, a lot 01-Nov-19 03:19 PM ah damn you were faster 01-Nov-19 03:19 PM But to see a source just like that, in the wild 01-Nov-19 03:19 PM Just burning up in snow 01-Nov-19 03:19 PM It's quite a terrifying thing 01-Nov-19 03:20 PM oh there are still a few left 01-Nov-19 03:20 PM even more reasons to carry a dosimeter 01-Nov-19 03:20 PM The ones left are pretty much inaccessible 01-Nov-19 03:20 PM (that's literally what they were made for - inaccessible regions) 01-Nov-19 03:20 PM yeah you'd think that 01-Nov-19 03:20 PM The ones that were able to be recovered were recovered by Mayak 01-Nov-19 03:20 PM ... and subsequently lost in warehouses 01-Nov-19 03:20 PM (don't tell anyone) 01-Nov-19 03:20 PM https://www.youtube.com/watch?v=WZi52vaTcZ8 01-Nov-19 03:21 PM that's a gamma defectoscope source 01-Nov-19 03:21 PM stolen from a work site 01-Nov-19 03:21 PM I'm talking about high activity sources in general ^^ 01-Nov-19 03:22 PM I'm pretty sure there's very few left 01-Nov-19 03:22 PM None as powerful as that insanity 01-Nov-19 03:22 PM depends on your definition I guess 01-Nov-19 03:22 PM 35kCi from an RTG 01-Nov-19 03:22 PM over 200C on the surface 01-Nov-19 03:22 PM because IMO even 10 sources out in the wild are a lot 01-Nov-19 03:22 PM most are in the form of unused/expired defectoscopes in and around Russia afaik 01-Nov-19 03:22 PM with the DU shielding around them 01-Nov-19 03:22 PM I like that in the video the guy says "fourty microsievert per hour" 01-Nov-19 03:22 PM And then in Russian you hear "three... three to four sievert" 01-Nov-19 03:24 PM heh 01-Nov-19 03:24 PM the scary thing is if you start adding up the amounts of materials seized when it is weapons grade 01-Nov-19 03:24 PM none of it is 01-Nov-19 03:24 PM orphan sources arent super scary unless you are right near them 01-Nov-19 03:24 PM even if you had an entire barrel packed full of these, you couldn't make anything besides a dirty bomb 01-Nov-19 03:25 PM yeah i wasnt talking about these, just something i learned a few months ago about the actual times weapons grade materials were seized 01-Nov-19 03:32 PM the video of this source recovery is...terrifying 01-Nov-19 03:32 PM is that all the training they gave those guys? 01-Nov-19 03:34 PM "when you hear the whistle, run for your lives" is the most foolproof training you can get 01-Nov-19 03:39 PM think they drew straws for who had to put the lid on the cask? 01-Nov-19 09:08 PM I think the Georgians were volunteers 01-Nov-19 09:08 PM Volunteers in the sense that they were told that this had to be done, so the people volunteered to do it 01-Nov-19 09:08 PM There's a very interesting guy on youtube by the name of Alexandr Kupnyi 01-Nov-19 09:08 PM He was the main photographer of the chernobyl power plant, went to the deepest depths of the sacrophagus/reactor and under-reactor buildings 01-Nov-19 09:08 PM Lots of content from him 01-Nov-19 09:08 PM Most of his videos are in Russian, but there's quite a few with subtitles, and lots of archive footage 01-Nov-19 09:08 PM https://www.youtube.com/channel/UC8qykrtgQ6sEve04wwuaRMA/videos 01-Nov-19 10:13 PM it surprises me that in most all of the videos from chernobyl in the basements and utility areas they always have a geiger counter/scintillator but i do not think i have ever seen someone with a gas monitor 01-Nov-19 10:13 PM maybe that just is not an issue but people i know who work in facilities maintenance in way less scary places carry them 01-Nov-19 10:13 PM especially in basements/enclosed spaces! 01-Nov-19 10:20 PM They're either well ventilated or the air is very dry and stale 10-Nov-19 09:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191110_145105-E42FD.jpg 10-Nov-19 09:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191110_175548-682A2.jpg 10-Nov-19 09:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191110_175952-F2CD5.jpg 10-Nov-19 09:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191110_172440-90AAC.jpg 10-Nov-19 10:27 AM That's a lotta space on top 10-Nov-19 10:28 AM I shortened the tube a bit, plus there has to be padding etc 10-Nov-19 10:30 AM I hope that's not a 39A 10-Nov-19 10:30 AM Soviet PMTs marked "A" are basically "bad grade" 10-Nov-19 10:31 AM no Idea 10-Nov-19 10:31 AM ФЭУ-39А 10-Nov-19 10:31 AM versus ФЭУ-39 10-Nov-19 10:31 AM but luckily it's not mine, made ot for a friend 10-Nov-19 10:31 AM or whatever that one is 10-Nov-19 10:31 AM ФЭУ-8something 10-Nov-19 10:31 AM 85? 10-Nov-19 10:32 AM I would have to get up and go to the basement to check 10-Nov-19 10:32 AM in short, there's an evil trick with these soviet PMTs 10-Nov-19 10:32 AM a lot of the cheap ones have horrible resolution because they're made for counting 10-Nov-19 10:32 AM above 9-10% 10-Nov-19 10:33 AM https://giphy.com/gifs/star-shooting-the-more-you-know-3og0IMJcSI8p6hYQXS 10-Nov-19 10:34 AM if you get a datasheet when you buy them, look out for "счётный" written anywhere on them 10-Nov-19 10:34 AM either in handwriting or printed text 10-Nov-19 10:34 AM that means "counting" and also means "resolution reject" 10-Nov-19 10:34 AM it's not mine 10-Nov-19 10:35 AM just making it known :P 10-Nov-19 10:35 AM I only have the tube and scintillator and was told to fabricoble a housing for it 10-Nov-19 10:37 AM Useful info for the future 10-Nov-19 10:37 AM If you want to build more of your own 10-Nov-19 10:37 AM I try to use hamamatsu PMTs whenever possible 10-Nov-19 10:38 AM that's a good idea 10-Nov-19 10:38 AM there is just too little information on the russian ones 10-Nov-19 10:38 AM I have a giant 150mm diameter photocathode PMT, NOS, from one of the soviet muon detectors 10-Nov-19 10:38 AM sounds like a "but" 10-Nov-19 10:39 AM I'm not an oil magnate and I don't have a corresponding scintillator 10-Nov-19 10:39 AM use water and build a cherenkov detector 10-Nov-19 10:39 AM that was one of their original uses 10-Nov-19 10:39 AM but I want a scintillator that will make this thing sniff out a smoke detector button from the front door of my apartment 10-Nov-19 10:39 AM hide it in the closet with an inconspicuous red light :P 10-Nov-19 10:42 AM any particular crystal in mind? 10-Nov-19 10:42 AM organics should not be a problem on this size 10-Nov-19 10:43 AM naw, if I get to pick I'm choosing hardcore 10-Nov-19 10:43 AM https://www.ebay.com/itm/223736209848 10-Nov-19 10:43 AM 150x150mm of NaI:Tl 10-Nov-19 10:43 AM SrI2:Eu! 10-Nov-19 10:43 AM oh lol 10-Nov-19 10:43 AM that listing is from an acquaintance! 10-Nov-19 10:43 AM he's the one that sent me the nanofocus x-ray tube 10-Nov-19 10:43 AM https://www.ebay.com/itm/NaI-Tl-150-100mm-Scintillation-gamma-detector-Resolution-12-Built-in-preamp/223616087601? 10-Nov-19 10:43 AM this is one of the detectors it was used for 10-Nov-19 10:43 AM a mindblowing resolution of... 12% 10-Nov-19 10:43 AM 1.5kHz background count rate lol 10-Nov-19 10:48 AM if he's a friend of yours why not ask him for the scintillator? 10-Nov-19 10:48 AM maxim should not have any issues on getting more 10-Nov-19 10:48 AM it's more of a "want" project 10-Nov-19 10:48 AM than a "need" project 10-Nov-19 10:48 AM I'm trying to not spend money like a wood chipper at the moment 10-Nov-19 10:51 AM but still 10-Nov-19 10:51 AM more detectors = more better 10-Nov-19 10:51 AM I have a whole box of detectors 10-Nov-19 10:51 AM most are scintillators... which is neat 10-Nov-19 10:52 AM I'm really starting to like gas proportional 10-Nov-19 10:52 AM still want to make my own, now that I can weld airtight and have a lot of argon at my disposal... 10-Nov-19 10:52 AM they had the cutest little thing at cern 10-Nov-19 10:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190915_164154-6F3B7.jpg 10-Nov-19 10:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190915_164208-16998.jpg 10-Nov-19 10:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190915_164200-AD1B6.jpg 10-Nov-19 10:52 AM I'm kind of regretting getting rid of my bottle P10 gas 12-Nov-19 12:41 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC02646-D6A94.JPG 12-Nov-19 12:41 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC02647-1F3D2.JPG 12-Nov-19 12:41 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC02648-79B26.JPG 12-Nov-19 12:41 AM A soviet BS7-W nanofocus tube! 12-Nov-19 12:41 AM It has arriiiiiiiived 12-Nov-19 12:57 AM cute! 12-Nov-19 12:57 AM doesn't look like much voltage? 12-Nov-19 01:05 AM All your x ray posts are starting to tempt me... 12-Nov-19 01:09 AM @AdamMcCombs I have a few spares that aren't as nano 12-Nov-19 01:09 AM @GigaSquirrel 15kV @ 26mW input, teeny weeny 12-Nov-19 01:09 AM I'm going to keep that in mind 12-Nov-19 01:09 AM But like my screen name is nanographs 12-Nov-19 01:09 AM So 12-Nov-19 01:10 AM You can make nanographs with sufficient collimation and distance 12-Nov-19 01:11 AM I'm also going to need that magic thing called time 12-Nov-19 01:11 AM I always give people the flashlight analogy - the bigger the focal spot of the x-ray tube, the larger the flashlight, and the blurrier the image up close, but far away it's still sharp. 12-Nov-19 01:11 AM The downside is the inverse square law and the inverted wallet law 12-Nov-19 01:12 AM Yeah it's the same thing in electron guns to a degree 12-Nov-19 01:12 AM The larger the distance, the more powerful your tube needs to be, and the more money you need to spend on shielding, the latter being exponentially tied to x-ray tube power 12-Nov-19 01:12 AM Eh 12-Nov-19 01:12 AM Lots of concrete 12-Nov-19 01:12 AM That implies you have a spare room :P 12-Nov-19 01:13 AM Yeah if I put it outside 12-Nov-19 01:13 AM I can build a concrete hut in like a day 12-Nov-19 01:13 AM A concrete hut with 30cm thick walls? 12-Nov-19 01:13 AM Interestingly someone sent me what appear to be xray images of some electronic device, to try and make a 3d model from 12-Nov-19 01:13 AM Easy 12-Nov-19 01:13 AM Like a small one just for the tube 12-Nov-19 01:14 AM @nmz787 I have a bit of software I found somewhere that does cone-beam CT reconstruction 12-Nov-19 01:14 AM (this is where I mention the family buisness is concrete) 12-Nov-19 01:14 AM Hmm I'm just trying meshroom right now 12-Nov-19 01:14 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/CBCT_tool-C4497.7z 12-Nov-19 01:16 AM Ok will try that now 12-Nov-19 01:16 AM Meshroom failed, I guess the images not being topology made it crazy 12-Nov-19 01:16 AM Well it produced something, but it's junk output 12-Nov-19 01:16 AM yeah that program is pretty nice 12-Nov-19 01:16 AM sadly closed source and the author never replied to my emails 12-Nov-19 01:18 AM Oh, and it's Windows 12-Nov-19 01:18 AM I guess I can try WINE 12-Nov-19 01:18 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/JPEG_20191112_012121-2A6E6.jpg 12-Nov-19 01:18 AM That's an example of one of the images 12-Nov-19 01:18 AM @AdamMcCombs really this whole vacuum thing is just a ploy to sell more concrete... :P 12-Nov-19 01:23 AM If that wasn't taken at the center, cone-beam reconstruction might fail 12-Nov-19 01:25 AM Is the output supposed to be the "raycast volume"? 12-Nov-19 01:25 AM That popup doesn't appear to be able to save a 3d file, like STL or OBJ 12-Nov-19 01:26 AM I have no idea 12-Nov-19 01:26 AM I'm just looking at the chicken example 12-Nov-19 02:23 AM Hmm, CBCT definitely gives a weird result, I guess these images really do need to just be of the item being rotated 15-Nov-19 03:26 PM Anyone have experience with the relatively cheap bicron scintillators on eBay? (for fast neutron detection) 15-Nov-19 03:26 PM https://www.ebay.com/itm/3-THREE-INCH-Diameter-BC412-Plastic-Scintillator-Scintillation-3-x2-1-4-Thick/261876504876 15-Nov-19 04:01 PM @GigaSquirrel someone summoned you 15-Nov-19 04:29 PM https://www.crystals.saint-gobain.com/sites/imdf.crystals.com/files/documents/bc400-404-408-412-416-data-sheet.pdf 15-Nov-19 04:29 PM looks like that should work if the ebay seller is correct? 15-Nov-19 04:53 PM I've seen the datasheet, but I'm more interested in their use in practice. Use of optical cement, practical energy resolution... so on 15-Nov-19 05:22 PM @Mason_Yu I have some slightly different Saint-Gobain scintillator 15-Nov-19 05:22 PM it's ok for detection at best 15-Nov-19 05:22 PM For gammas/x-rays or neutrons? 15-Nov-19 05:23 PM both should work, though I don't have a bag of neutrons handy 15-Nov-19 05:23 PM look for some lithium-based scintillators 15-Nov-19 05:23 PM there were some boards up on ebay that had tiny little Scionix PMT+Li-something crystals 15-Nov-19 05:24 PM So these Saint-Gobain ones are worse than NaI:TI? 15-Nov-19 05:24 PM far far worse 15-Nov-19 05:24 PM Okay, good to know 15-Nov-19 05:24 PM anything plastic is garbage compared to NaI in general 15-Nov-19 05:24 PM but it's cheap 15-Nov-19 05:24 PM but for neutron detection, gamma/x-ray scintillators have very bad conversion - you really want either a neutron tube or a neutron scintillator 15-Nov-19 05:28 PM Would you recommend the soviet He-3 tubes then? I remember you saying that most of them have leaked. 15-Nov-19 05:28 PM they'd still be better than small gamma scintillators 15-Nov-19 05:28 PM go for it 15-Nov-19 05:29 PM you are the first and only person i've heard of with leaking issues from 3He tubes fwiw 15-Nov-19 05:29 PM but, yeah, the LiI(Eu) scintillators from scionix are an option, but they're super duper fragile 15-Nov-19 05:30 PM they're vintage soviet tubes, they eventually drift 15-Nov-19 05:30 PM been meaning to truss one'o mine up 15-Nov-19 05:30 PM if you luck out and get something from the nineties, they'll probably be very good 15-Nov-19 05:30 PM but if it's a dinosaur from the seventies, they may or may not be dead, or just out of spec 15-Nov-19 05:30 PM just have to say that this only happens with helium tubes, all other soviet tubes are fine since they have the standard mix 15-Nov-19 05:32 PM the scionix scintillators also have a polyethylene slug around 'em for moderation, i am not sure what easily accessible options exist for fast neutron spectrometry tbh 15-Nov-19 05:33 PM are we talking about the same scintillator? 15-Nov-19 05:33 PM the ones used in the exploranium? 15-Nov-19 05:33 PM I remember them just being tiny tubes with PMT pins on the bottom, soldered directly into some sort of board 15-Nov-19 05:33 PM or whatever it's called 15-Nov-19 05:33 PM probably from the exploranium? 15-Nov-19 05:33 PM I want an exploranium, but they're a pain to find cheap 15-Nov-19 05:33 PM yeah; they have a PE thing around the tube with a little LND GM tube tucked right near it too 15-Nov-19 05:34 PM I think they're boards from the highest end gr-135+ option 15-Nov-19 05:36 PM fast neutron detection without moderation seems like the realm of fission chamber detectors 15-Nov-19 05:36 PM fission chamber detectors!? 15-Nov-19 05:36 PM that's the impression i get, yeah 15-Nov-19 05:36 PM Not something I can do unfortunately 15-Nov-19 05:36 PM yeah 15-Nov-19 05:37 PM TIl this exists 15-Nov-19 05:37 PM yeah they're like incore flux monitors for reactors 15-Nov-19 05:37 PM it looks pretty DIYable 15-Nov-19 05:37 PM assuming you can get a vial of U-235 15-Nov-19 05:37 PM That's the problem lol 15-Nov-19 05:38 PM carl willis definitely pontificated about hobbyist fission chamber manufacturing in his ore-to-uranium blog post 15-Nov-19 05:38 PM i do not recommend the thing 15-Nov-19 05:38 PM getting a NORM uranium mix is easy 15-Nov-19 05:38 PM (in some countries) 15-Nov-19 05:38 PM would it work though? 15-Nov-19 05:39 PM we need a bot that can pull up ENDF graphs 15-Nov-19 05:50 PM Unfortunately it looks like fission chambers only work with quite a lot of fissile material in the coating, since it has to be fairly thin 15-Nov-19 05:50 PM https://www.ebay.com/itm/THERMO-INDENTIFINDER-TARGET-HE-3-9V-ISOTOPE-RADIATION-SPECTROMETER/272407454468?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D60709%26meid%3Debad923d5cc8481aa86dd0263d0f9b72%26pid%3D100005%26rk%3D1%26rkt%3D12%26mehot%3Dco%26sd%3D323937193614%26itm%3D272407454468%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851 15-Nov-19 05:50 PM I want this 15-Nov-19 05:50 PM All things considered $1000 is not a very bad price and this guy's got a bunch of them 15-Nov-19 06:08 PM Sorry for the link 15-Nov-19 06:20 PM looks like he sold one for $850.00 in march... should message him and ask for a deal 15-Nov-19 06:21 PM That's still above my budget, but no harm in asking I guess 15-Nov-19 06:21 PM i have gotten some crazy deals on eBay by asking. 15-Nov-19 06:21 PM sometimes the sellers get a bit offended but it usually depends what kinda deal you are asking them to work 15-Nov-19 06:22 PM hey so, somethin' i'm kinda fuzzy on still 15-Nov-19 06:22 PM what's a 'good' resolution for a NaI(Tl) detector? 15-Nov-19 06:22 PM some papers i've read are like 'the intrinsic resolution is ~7%' but i've also seen lower advertised or reported through various means 15-Nov-19 06:24 PM http://scintillator.lbl.gov/ 15-Nov-19 06:25 PM holy cow there's a lot 15-Nov-19 06:26 PM Everything you'd want to know, would be nice if they tell you if it's hygroscopic though 15-Nov-19 06:26 PM And for organic scintillators 15-Nov-19 06:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-963D1.png 15-Nov-19 06:34 PM apparently you can use pure sodium iodide if you get it really cold, neat 15-Nov-19 11:32 PM @Mason_Yu Aye, I played around with some BC412 for Neutron detection 15-Nov-19 11:32 PM it's blind to the 59 keV gammas from Am, but sees AmBe very well 16-Nov-19 12:17 AM @GigaSquirrel tried taking a super thin slice of it? 16-Nov-19 12:17 AM with a hot knife or something 16-Nov-19 02:15 AM nope 16-Nov-19 10:47 AM https://old.reddit.com/r/whatisthisthing/comments/dx69ye/found_in_a_crawlspace_of_a_house_from_the_80s/ 16-Nov-19 10:47 AM ...talk about nightmare finds in an old house 16-Nov-19 10:47 AM and the link to the comment with the photo of the actual source boxes: https://old.reddit.com/r/whatisthisthing/comments/dx69ye/found_in_a_crawlspace_of_a_house_from_the_80s/f7njm5k/ 16-Nov-19 11:34 AM One of the only useful comments, beside all the ridiculous panic, says it's a vintage Western Electric tube with a hot fill gas 16-Nov-19 11:44 AM looks like insane overkill if it is just some old tubes 25-Nov-19 01:06 PM oh wow 25-Nov-19 01:06 PM I got one of those gamma-scout thingies from work 25-Nov-19 01:06 PM and wow, I know it was bad, but I did not expect it to be that bad 25-Nov-19 01:06 PM constantly drops out, the battery can't support the LCD and beeper at the same time, the unit it shows are absolut garbage 25-Nov-19 01:06 PM Becquerel instead of CPS?! 25-Nov-19 01:06 PM you have to press a button with a trefoil on it to show "µSv/h" 25-Nov-19 01:06 PM from a non compensated tube 25-Nov-19 01:06 PM it can display the average doserate over the last 24h 25-Nov-19 01:06 PM which is 0.1 µSv/h according to this thing 25-Nov-19 01:06 PM ...which sat at ~1 mSv/h for the last 4 hours 25-Nov-19 01:22 PM (that should read 250 mSv/h beta) 25-Nov-19 01:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191125_222110-7BF37.jpg 25-Nov-19 02:06 PM To be fair it does show "OVERFLOW" 25-Nov-19 02:06 PM Also is the battery fresh in this unit? 25-Nov-19 02:06 PM They have a non-replaceable battery that is supposed to last a few years 25-Nov-19 02:07 PM no idea how old it is 25-Nov-19 02:07 PM I know, can't really blame it for the overflow thingy 25-Nov-19 02:07 PM If it's dipping out the LCD when the beeper clicks, the battery must be near-dead 25-Nov-19 02:07 PM It's a primary cell 25-Nov-19 02:07 PM but all the other points still stand 25-Nov-19 02:07 PM even just soldering in a battery is stupid 25-Nov-19 02:07 PM You're supposed to ship it off to be replaced, because it loses calibration 25-Nov-19 02:07 PM A total shot-in-the-darkfoot design 25-Nov-19 02:07 PM To replace the battery yourself(which VOIDS THE WARRANTY!) you have to connect a power supply in parallel and keep it on as you're soldering 25-Nov-19 02:07 PM It's ridiculous 25-Nov-19 02:07 PM And yeah, no energy compensation on a thin window tube 25-Nov-19 02:07 PM I suppose it's calibrated to show you uSv at 662 or something 25-Nov-19 02:09 PM I thought at least the gamma filter presented some kind of compensation, even if it was only in one direction 25-Nov-19 02:09 PM but nope 25-Nov-19 02:09 PM 4mm al, lol 25-Nov-19 02:10 PM Converts Beta To Equivalent X-rays™ 25-Nov-19 02:10 PM (which will immediately go inside the tube because it's got a Be window) 25-Nov-19 02:11 PM it's such a terrible design why is it so popular 25-Nov-19 02:11 PM probably because it was one of the only options, plus grandfathering 25-Nov-19 02:11 PM also did you see how ridiculously expensive it is? 25-Nov-19 02:11 PM they could have at least installed a microswitch so it will only show counts unless the beta filter is in place 25-Nov-19 02:11 PM YES 25-Nov-19 02:12 PM the beta filter doesn't even really work 25-Nov-19 02:12 PM since it'll still see beta as x-rays 25-Nov-19 02:13 PM that's a different point 25-Nov-19 02:13 PM or not put a trefoil button on there 25-Nov-19 02:13 PM the design is such a weird unicorn 25-Nov-19 02:13 PM not call cpm Bq 25-Nov-19 02:14 PM there's so many things wrong or unusual with it 25-Nov-19 02:14 PM it's got many of the "why does it do that?" points 25-Nov-19 02:15 PM is it just me or is the trefoil crooked af? 25-Nov-19 02:15 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191125_231439-FDD14.jpg 25-Nov-19 02:15 PM nope that's very crooked 25-Nov-19 02:15 PM how do you mess up silkscreening so bad? 25-Nov-19 02:16 PM with german engineering 25-Nov-19 02:16 PM xD 25-Nov-19 02:16 PM no idea 25-Nov-19 02:16 PM gotta go to bed now 25-Nov-19 02:16 PM will continue complaining tomorrow 25-Nov-19 10:44 PM https://www.ebay.de/itm/113975659200 25-Nov-19 10:44 PM any Idea what kind of x-ray tube that is? 25-Nov-19 10:44 PM it looks very weird IMO 25-Nov-19 10:44 PM looks a bit like a diffraction tube 26-Nov-19 12:19 AM It is. 26-Nov-19 12:19 AM it's either refraction or structural analysis 26-Nov-19 12:19 AM 40kV, 4.5mA 26-Nov-19 12:19 AM 3mm focal spot 26-Nov-19 12:19 AM that's all I can find 26-Nov-19 12:19 AM other, stubbier BSV tubes are all for XRF/XRD 26-Nov-19 12:19 AM HUGE focal spots, useless for imaging 26-Nov-19 12:19 AM @GigaSquirrel 26-Nov-19 12:19 AM BS tubes on the other hand(not BSV) are great microfocus-ish tubes. 26-Nov-19 12:30 AM ahh, that explains a lot 26-Nov-19 06:05 AM https://www.youtube.com/watch?v=ex5rJjmtLgQ 26-Nov-19 03:25 PM ohhh, the gamma scout 26-Nov-19 03:25 PM i remember that being the one (1) geiger counter that a popular science-toy catalog sold, back when i was a kid 26-Nov-19 03:25 PM good to know it's a piece of junk, explains why i literally never see them anywhere :D 27-Nov-19 01:04 PM @Deleted User I ended up grabbing that xray controller 27-Nov-19 01:10 PM Which one? 27-Nov-19 01:10 PM https://hgrinc.com/productDetail/Electronics/USED-CR-TECHNOLOGY-XRAY-CONTROL-UNIT/06181420008/ 27-Nov-19 01:10 PM Oh, that one 27-Nov-19 01:11 PM I'll still need to locate a tube, but $70 27-Nov-19 01:11 PM Could probably sell the printer for what you bought it for 27-Nov-19 01:11 PM Those printers are expen$ive even used 27-Nov-19 01:11 PM Isn't it just a standard video printer? 27-Nov-19 01:11 PM It is, but holy hell they're expensive 27-Nov-19 01:11 PM Also talk to @TecKonstantin, he's reverse-engineering a head that is compatible with this 27-Nov-19 01:11 PM You could use each others help :P 27-Nov-19 01:12 PM oh that is hilarious...didnt realize there used to be an xray controller manufacturer in my area haha 27-Nov-19 01:13 PM Well it'll be at minimum a few weeks before there's even a chance it'll be in my possession but it's been purchased and on hold for pickup 27-Nov-19 01:13 PM I believe this is the business end of your unit @Treehouseman https://www.ebay.com/itm/THALES-TH-9464-HPH101VR12-ND-X-ray-Imaging-Intensifier-Tube-HAMAMATSU-L7902/163883154672 27-Nov-19 01:13 PM with that intensifier 27-Nov-19 01:13 PM oh that intensifier is sexy 27-Nov-19 01:13 PM directly to usb 27-Nov-19 01:13 PM my kind of webcam, only need to make sure you have enough backlight 27-Nov-19 01:14 PM Thales though 27-Nov-19 01:14 PM you'll NEVER get the documentation 27-Nov-19 01:15 PM would be too easy otherwise 27-Nov-19 01:15 PM well, the PSU should be inside 27-Nov-19 01:15 PM and intensifiers just need volts to work 27-Nov-19 01:15 PM yep 27-Nov-19 01:16 PM Also, an interesting diagram of how the Hamamatsu tubes work and why they have that nib on the side 27-Nov-19 01:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/US5077771-drawings-page-16-8AE73.png 27-Nov-19 01:16 PM basically the entire x-ray tube is on the outside of the actual tube unit 27-Nov-19 01:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/HTB1pG_bf_AKL1JjSZFCq6xFspXa5-03312.png 27-Nov-19 04:12 PM @Treehouseman oh yes info about the controllers would be nice, the heads are not that expensive, depends mostly on shipping and a bit of luck 27-Nov-19 04:12 PM also a nice image, i think Kevex has most of the patent rights i think 27-Nov-19 04:12 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/US6229876-drawings-page-6-BD4F6.png 27-Nov-19 04:24 PM Well once I have it I can see about doing some reverse engineering for you 27-Nov-19 04:24 PM are the cables an issue to obtain as well? 27-Nov-19 04:25 PM If you don't like spending hundreds of dollars for a plug, yes 27-Nov-19 04:25 PM A goes to A, B goes to B... an hour later, you've got a free cable that you can't pull out. 27-Nov-19 04:27 PM yes i think they are probably straight through 27-Nov-19 04:27 PM @Treehouseman no hurry, at the moment i dont have much time to work on it unfortunately, so im not in a pinch. 27-Nov-19 04:29 PM Let's not mention that you just casually almost redrew the entire PCB already 27-Nov-19 04:29 PM :P 27-Nov-19 04:30 PM it was only 2 layer, that was maybe 2h work 27-Nov-19 04:30 PM We need a KiCAD Reverse Engineer Edition 27-Nov-19 04:30 PM you draw the PCB first, then replace pads with footprints, then they pop up in the schematic and get connected by nets 27-Nov-19 04:33 PM it has been a long time since i last did some reversing, so i just had to do it ;), yes PCB first and then imported the Net list to a schematic. There is where the fun begins ;). to entnagel all the connections 27-Nov-19 04:33 PM well, what you could do is now open a second instance, place all the components, and replace the dumb pinouts 27-Nov-19 04:35 PM the components are placed but i want a schematic i can read proper to see where the loops are and control signals 27-Nov-19 04:35 PM i found so far some interesting things and some errors they must have happend either in the layout or schematic design, for example they forgot to connect some resistors, they are only connected on one side ^^ 27-Nov-19 04:45 PM could be bodge options 27-Nov-19 04:51 PM i would not think so, one of them is a simple discharge resistor and it is in a power plane, they probably did not see it 27-Nov-19 04:51 PM the design looks a bit rushed, such things can and do happen 28-Nov-19 02:03 AM yay, space blankets are alpha transparent! 28-Nov-19 02:03 AM sadly they also let a bit of light through 28-Nov-19 03:23 AM The importance of field-forming! 28-Nov-19 04:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D4A69.png 28-Nov-19 04:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/bling-bling-goldvektor-24435990-056DC.png 29-Nov-19 09:36 PM That poor Ludlum is screaming for its life!! Hahahaha 30-Nov-19 01:07 PM all that work for nothing, because this arived today 30-Nov-19 01:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191130_211609-F13EA.jpg 30-Nov-19 01:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191130_211637-2C6CD.jpg 30-Nov-19 01:13 PM Didn't know you could order empty bags from digikey 30-Nov-19 01:15 PM I want some alpha scintillator 30-Nov-19 01:15 PM But they're expensive, fragile, and unobtainium 30-Nov-19 01:15 PM Since it has to be single-digit microns thick and perfectly light tight 30-Nov-19 01:15 PM Regular space blankets don't work like that 30-Nov-19 01:16 PM I have some pure CsI here I want to try as alpha spectrometer, according to some papers 5% FWHM are achievable 30-Nov-19 01:16 PM I have CsI:Tl in powder form 30-Nov-19 01:16 PM From cutting residues 30-Nov-19 01:16 PM regular space blankets won't work, but these do 30-Nov-19 01:16 PM too thick for scints though 30-Nov-19 01:16 PM aren't they? 30-Nov-19 01:16 PM sure I'll lose some resolution 30-Nov-19 01:16 PM but it would be fun to play around with 30-Nov-19 01:17 PM https://www.ebay.com/itm/ALPHA-SCINTILLATION-DETECTOR-ZnS-Ag-FEU-19/264389485672 30-Nov-19 01:17 PM interesting chunker 30-Nov-19 01:17 PM if I really need high precision alpha spectrometry I'll just go and get some of my semiconductor detectors 30-Nov-19 01:17 PM psh 30-Nov-19 01:17 PM but ZnS will not give you any resolution 30-Nov-19 01:18 PM sensitivity more than resolution 30-Nov-19 01:18 PM yep 30-Nov-19 01:18 PM oh and I also got an unpotted pin diode today, will play around with that a bit :3 30-Nov-19 01:19 PM you can dissolve BPW-34 housings with... I want to say MMA? 30-Nov-19 01:19 PM or MEK 30-Nov-19 01:19 PM or MEKP but that's classified as a big boomy no chemical 30-Nov-19 01:19 PM I know 30-Nov-19 01:19 PM but those are tiny 30-Nov-19 01:20 PM have you tried those chinese 1010CE detectors? 30-Nov-19 01:20 PM the 10x10mm "photodiodes" 30-Nov-19 01:20 PM nope 30-Nov-19 01:20 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191130_214017-1510A.jpg 30-Nov-19 01:20 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191130_214036-A8070.jpg 30-Nov-19 01:21 PM that doesn't look uncovered 30-Nov-19 01:21 PM looks like there's a filter on top 30-Nov-19 01:21 PM but they also look potted 30-Nov-19 01:21 PM they are 30-Nov-19 01:22 PM plus I'm not sure if they are PIN or PN 30-Nov-19 01:22 PM do you know those huge hamamatsu s1337 photodiodes reps recently showed 30-Nov-19 01:22 PM I do 30-Nov-19 01:22 PM they came from me 30-Nov-19 01:22 PM This means I have contacts in the right places. 30-Nov-19 01:23 PM when I bought them I was hoping they were PIN, but they are PN 30-Nov-19 01:23 PM https://www.ebay.com/itm/Nuclear-Radiation-Detector-Counter-Gamma-Beta-Spectrometer-for-ANDROID/352671962476 30-Nov-19 01:23 PM this guy claims that it's an actual scintillator with a preamp and spectrometer 30-Nov-19 01:23 PM It's a total joke but I'm still curious as to what's inside 30-Nov-19 01:24 PM maybe some BGO and an APD 30-Nov-19 01:24 PM it has a resolution of "yup, it's a spectrum" 30-Nov-19 01:24 PM of course, at that size 30-Nov-19 01:24 PM I want a wire bonder! 30-Nov-19 01:24 PM Then I can build actual micro spectrometers 30-Nov-19 01:25 PM but why 30-Nov-19 01:25 PM Bond bare 0.5x0.5mm crystals together on a tiny ceramic hybrid 30-Nov-19 01:25 PM tiny spectrometers are dumb 30-Nov-19 01:25 PM isotope identifiers 30-Nov-19 01:25 PM just like those 5x5x5 mm CZTs, sure they can have a great resolution, but only below 600 keV 30-Nov-19 01:26 PM CZTs also cost like ten times their weight in gold 30-Nov-19 01:26 PM and if you take a 0.5x0.5mm crystal you can do 100 keV at best 30-Nov-19 01:26 PM I think the 5x5x5 crystals were like $600 30-Nov-19 01:26 PM each 30-Nov-19 01:26 PM yep, roundabout that 30-Nov-19 01:26 PM still pretty cheap when it comes to rad detectors 30-Nov-19 01:26 PM here's an idea for the true rad nuts 30-Nov-19 01:26 PM a good scintillator won't be any cheapter 30-Nov-19 01:27 PM czochralski at home 30-Nov-19 01:27 PM oh I've thought about that 30-Nov-19 01:27 PM SrI2:Eu made at home 30-Nov-19 01:27 PM it's somewhere on the project list 30-Nov-19 01:28 PM https://www.mtixtl.com/CdZnTe-c-050510S2.aspx 30-Nov-19 01:28 PM AAAAAAAAAAAAAAAA 30-Nov-19 01:28 PM 25mm^3 for $260 30-Nov-19 01:28 PM thing costs more than diamonds, let alone gold 30-Nov-19 01:29 PM do you have any idea what "real" detectors cost xD 30-Nov-19 01:29 PM on the subject of SiPIN stuff are these decent for anything? https://www.ebay.com/itm/202692988023 30-Nov-19 01:29 PM not radiation detection 30-Nov-19 01:29 PM picked up a couple for like $5 each shipped a couple years ago but havent bothered to play with them lol 30-Nov-19 01:30 PM oi, I'm pretty sure they're exactly what I have here (pics above), mine are from thorlabs powermeters 30-Nov-19 01:30 PM yep 30-Nov-19 01:30 PM might work for alpha detection 30-Nov-19 01:30 PM think i was planning on sticking both of them on some plastic scintillator but never bought any 30-Nov-19 01:31 PM gnah they're PN :/ 30-Nov-19 01:31 PM might work with scintillators, but it will be close 30-Nov-19 01:31 PM anyways, @Deleted User Due to a lack of resolution CZTs are actually really cheap 30-Nov-19 01:31 PM HPGes are >$1k per % of relative effciency 30-Nov-19 01:34 PM HPGes start at $5-10k 30-Nov-19 01:34 PM unless you score something vintage off eBay 30-Nov-19 01:34 PM which has probably been thermally shocked to death 30-Nov-19 01:34 PM and/or abused in high rad fields 30-Nov-19 01:34 PM @Goldsteel works with very high end HPGe and knows all about them 30-Nov-19 01:35 PM I'm talking new, the ebay prices vary strongly 30-Nov-19 01:35 PM New is $5-10k easily 30-Nov-19 01:35 PM for the tiny ones 30-Nov-19 01:35 PM How tiny? 30-Nov-19 01:35 PM Oh, you mean 5-10k, yeah 30-Nov-19 01:35 PM Very small 30-Nov-19 01:40 PM ? 30-Nov-19 01:40 PM yes. 30-Nov-19 01:40 PM you wont get them cheap 30-Nov-19 01:40 PM told 'ya 30-Nov-19 01:41 PM mine cost 200 thousand usd 30-Nov-19 01:41 PM lmao 30-Nov-19 01:41 PM lemme guess, 80% N type or something alike? 30-Nov-19 01:42 PM a lot of the thorlabs equipment has terrible stability if you are working with unfiltered AC 30-Nov-19 01:42 PM just an fyi 30-Nov-19 01:42 PM i was working with some for laser alignment stuff, just photosensors 30-Nov-19 01:42 PM garbage 30-Nov-19 01:42 PM good to know, thanks 30-Nov-19 01:42 PM i have a plot of how bad it is 30-Nov-19 01:42 PM i have a 70% rel eff at 1332keV compared to NaI 30-Nov-19 01:42 PM its N type 30-Nov-19 01:43 PM so close 30-Nov-19 01:43 PM new generation large crystal and my fwhm at 121keV is 400eV 30-Nov-19 01:43 PM afaik nothing better exists 30-Nov-19 01:44 PM none that I've heard of 30-Nov-19 01:44 PM nice 30-Nov-19 01:44 PM my crystal is 71.5mm wide 30-Nov-19 01:44 PM 76.8mm long 30-Nov-19 01:44 PM catches everything 30-Nov-19 01:45 PM I only have a 20% one with 2 keV FWHM that still needs some repairs... 30-Nov-19 01:45 PM 2 is normal 30-Nov-19 01:45 PM i drop to 2.35 or so at 3MeV 30-Nov-19 01:45 PM im specifically using this for gamma ray spectroscopy so i need the precision to split up traditionally doubly counted peaks 30-Nov-19 01:45 PM ive theorised that i can identify the gender of the operator based on the iodine line ambiently 30-Nov-19 01:45 PM thyroid 30-Nov-19 01:46 PM pfft, that's nothing! 30-Nov-19 01:46 PM I've seen setups where you could even tell which specific operator was using it! 30-Nov-19 01:46 PM ...based on the contamination levels afterwards 30-Nov-19 01:47 PM depending on what you tag each person with 30-Nov-19 01:47 PM i have to deal with a lot of dirty background from the building because everythings just concrete 30-Nov-19 01:48 PM don't forget pb-209 30-Nov-19 01:48 PM eh i pick up lead lines but even terrible ones can 30-Nov-19 01:48 PM they're a nuisance 30-Nov-19 01:48 PM id rather remove my lead lines than deal with the enormous k40 spike 30-Nov-19 01:48 PM i can discriminate off the lead 30-Nov-19 01:48 PM cant for the K40 30-Nov-19 01:49 PM not something you hear outside scientific gear 30-Nov-19 01:49 PM "enormous k40 spike" 30-Nov-19 01:49 PM then I walk into the room with a smoke detector 30-Nov-19 01:49 PM its my second largest background consideration after the xrays 30-Nov-19 01:49 PM every discord im in has a 'things only goldsteel says' log 30-Nov-19 01:50 PM well when you work with sensitive enough gear you'll just start saying those things 30-Nov-19 01:51 PM Y88 has a decay at 1.836MeV very close to a BSM candidate decay for high muon flux experiments looking for CLFV 30-Nov-19 01:51 PM A friend of mine went "I can't wait for winter when the air is finally dry enough for me to measure my high value resistors" once 30-Nov-19 01:51 PM so its ideal for calibration for me 30-Nov-19 01:51 PM problem is 30-Nov-19 01:51 PM nobody has any 30-Nov-19 01:51 PM when i presented this to the weekly meeting they informed me that they could purchase some and it would take so many months blah blah 30-Nov-19 01:51 PM i said dont worry 30-Nov-19 01:51 PM ill make it 30-Nov-19 01:51 PM ¯\_(ツ)_/¯ 30-Nov-19 01:53 PM I was about to say, you sound like someone who can just order some from the closest reactor... 30-Nov-19 01:53 PM neutron tank 30-Nov-19 01:53 PM LiBe, graphite blocks 30-Nov-19 01:53 PM dunk at the right distance 30-Nov-19 01:55 PM well the synthesis looks horrible 30-Nov-19 01:55 PM set neutron oven at e18 celsius neutrons per second and bake for 48 hours 30-Nov-19 01:55 PM the natural Y isotopes are heavier, so it's not just capture and enrich 30-Nov-19 01:55 PM yup 30-Nov-19 01:56 PM well good luck with that xD 30-Nov-19 01:56 PM might be a fission fragment with some luck 30-Nov-19 01:58 PM you start with strontium 30-Nov-19 01:58 PM Sr87 should capture a neutron to Sr88 then beta decay to Y88 30-Nov-19 01:58 PM but... 30-Nov-19 01:58 PM Sr88 is stable 30-Nov-19 01:58 PM its the most common isotope 30-Nov-19 01:58 PM i dont have a cyclotron 30-Nov-19 01:58 PM so my hope is 30-Nov-19 01:58 PM strontium88 captures to strontium89 30-Nov-19 01:58 PM decays to Y89 30-Nov-19 01:58 PM knocks a neutron out at higher energies to become 88 30-Nov-19 01:58 PM the 89 is long lived 30-Nov-19 01:58 PM the issue is just how long i can spend trying to knock neutrons out of the material 30-Nov-19 02:03 PM that's 30-Nov-19 02:03 PM uhm 30-Nov-19 02:03 PM optimistic 30-Nov-19 02:03 PM cheap, though 30-Nov-19 02:04 PM but Y88 also has a high-ish neutron capture cross section 30-Nov-19 02:04 PM thats why i need to do two dunkings at different energies 30-Nov-19 02:05 PM oh, if that's something you can do 30-Nov-19 02:05 PM first of all you have my jealousy 30-Nov-19 02:05 PM secondly that would make things a lot easier 30-Nov-19 02:06 PM if it just isnt effective then all i do is work with something else 30-Nov-19 02:06 PM i mean realistically i could use... 30-Nov-19 02:06 PM http://nucleardata.nuclear.lu.se/toi/Gamma.asp?sql=&Min=1790&Max=1810 30-Nov-19 02:06 PM something here 30-Nov-19 02:06 PM didnt really want an isotope that lasted 10 minutes lmao 30-Nov-19 02:06 PM i could use rubidium if i had enough of it and ran across the room maybe 30-Nov-19 02:10 PM from your desktop easy bake neutron oven 30-Nov-19 02:10 PM its more like a frier 30-Nov-19 02:10 PM honestly 30-Nov-19 02:10 PM only... 30-Nov-19 02:10 PM i cook nucleons 30-Nov-19 02:10 PM with additional nucleons going fast 30-Nov-19 02:10 PM damnit 30-Nov-19 02:10 PM i have to compromise 30-Nov-19 02:10 PM decay time, spectrum cluttering and gamma fraction 30-Nov-19 02:10 PM and how easy it is to make 30-Nov-19 02:12 PM just don't let anyone drop a chunk of cobalt in there 30-Nov-19 02:12 PM nobody is that stupid 30-Nov-19 02:13 PM it sounds like you need an xfel 30-Nov-19 02:13 PM besides 30-Nov-19 02:13 PM never underestimate stupidity 30-Nov-19 02:13 PM i have the box that if you open it you die 30-Nov-19 02:13 PM what box is that? 30-Nov-19 02:13 PM thats way cooler 30-Nov-19 02:13 PM decomissioned medical cs source 30-Nov-19 02:13 PM its huge 30-Nov-19 02:13 PM why 30-Nov-19 02:13 PM im using it for throughput tests at 662 duh 30-Nov-19 02:14 PM because it can kill you when you open it, isn't that enough of a reason 30-Nov-19 02:14 PM I'll need to send you my prototype devices to test with actual loads 30-Nov-19 02:14 PM box that, if you look at it funny, kills you 30-Nov-19 02:14 PM "it hugged a chunk of cesium and survived" 30-Nov-19 02:14 PM "here's a stamp" 30-Nov-19 02:14 PM people keep DMing me 30-Nov-19 02:14 PM PUT 30-Nov-19 02:14 PM A SPIDER 30-Nov-19 02:14 PM IN IT 30-Nov-19 02:14 PM or whatever 30-Nov-19 02:14 PM PUT FOOD IN IT 30-Nov-19 02:14 PM just tell them that most of their food is already put next to one 30-Nov-19 02:15 PM keep it open as an ozone generator 30-Nov-19 02:15 PM people dont understand radiation 30-Nov-19 02:15 PM mmmmmmmm ions 30-Nov-19 02:15 PM can you actually measure the dose? 30-Nov-19 02:15 PM sure i can 30-Nov-19 02:15 PM it'd be interesting to see how generic non-rad-hard chips die 30-Nov-19 02:15 PM at how many krad 30-Nov-19 02:15 PM it whited our ccd out lmao 30-Nov-19 02:15 PM gives a new meaning to gamma camera 30-Nov-19 02:15 PM hey shall we open the box 30-Nov-19 02:15 PM sure ok 30-Nov-19 02:15 PM camera: AAAAAAAAAAAAAAAAAAAAAAA 30-Nov-19 02:15 PM perhaps not 30-Nov-19 02:16 PM buy a chunk of lead and bore a tiny hole through it 30-Nov-19 02:16 PM make a microfocus gamma source 30-Nov-19 02:16 PM its in a huge lead safe inside a barrel with a thing with a flap 30-Nov-19 02:16 PM so i mean 30-Nov-19 02:16 PM it could become 'hole that kills you' 30-Nov-19 02:17 PM the forbidden rabbit hole 30-Nov-19 02:17 PM forbidden fleshlight 30-Nov-19 02:17 PM hey man do you want ball cancer 30-Nov-19 02:18 PM if you stay long enough you can get both cancer and therapy 30-Nov-19 03:42 PM LMAO 30-Nov-19 03:42 PM The killing box 03-Dec-19 05:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191203_134952-BAFB6.jpg 03-Dec-19 05:15 AM I wanna combine this with the death box from @Goldsteel and make a flashlight 03-Dec-19 05:47 AM You meant... FLESHLIGHT 03-Dec-19 05:50 AM pretty sure I don't :P 03-Dec-19 09:07 AM Glow baby glow 04-Dec-19 12:21 PM The old adult filter didn't catch that one... 04-Dec-19 01:44 PM https://youtu.be/q1ZGnafdj2M 04-Dec-19 01:45 PM I already like his voice 04-Dec-19 01:46 PM heh figured not everyone would see it fly across twitter 04-Dec-19 01:46 PM saw it on the train and wanted to watch it at home, forgot about it 04-Dec-19 01:46 PM thanks! 06-Dec-19 01:43 AM https://www.whio.com/news/state--regional/nuclear-device-prompts-evacuation-hazmat-bomb-squad-called-columbus-neighborhood/3gxAqVg12oFUoqlcFnbZ4I/ 06-Dec-19 01:43 AM "In a 911 call, a man said he was working on a quantum physics generator in his garage and that he suffered radio-frequency burns. Fire officials said the words the man used in the call were “alpha waves and particle accelerator,” which led to concerns over radiation" 06-Dec-19 01:43 AM hahahaha 06-Dec-19 01:43 AM gotta use that next time someone asks about something i dont feel like explaining "oh its a quantum physics generator" 06-Dec-19 01:45 AM A quantum physics generator? Shouldn't we solve the ones we have before making new ones? 06-Dec-19 12:20 PM scary that the person is facing lots of fines for doing nothing wrong or illegal 06-Dec-19 12:20 PM ultimately their only folly is a scientifically illiterate populace 06-Dec-19 12:20 PM "and officials plan to file inducing panic charges against him" .. sigh 06-Dec-19 02:24 PM hopefully those plans do not go anywhere with the basically obvious mental health issues involved... depends if it was that or just a really stupid prank 06-Dec-19 02:24 PM if it was a prank maaaaaybe throw half the book at them 06-Dec-19 02:37 PM I don't think that it was a prank 06-Dec-19 02:37 PM honestly it sounds like someone who absolutely doesn't know what they're doing 06-Dec-19 02:39 PM @GigaSquirrel so apparently stoppi lives in murricah? 06-Dec-19 02:39 PM like those folks who build a sphere-shaped glow lamp, get a plasma to ignite an say they've built a fusion reactor and will solve the worlds energy problems 06-Dec-19 06:01 PM it definitely sounds like the person had, like, a psychotic break or something 06-Dec-19 06:01 PM i hope he'll be alright, mostly; some big brouhaha like this over what was likely a temporary mental crisis is like.. the worst thing in the world 06-Dec-19 06:03 PM Charge the news outlets with the panic charge as well 06-Dec-19 06:03 PM news outlets subsist off of stoking panic tbcf 06-Dec-19 06:03 PM i sort of livetweeted that whole news event yesterday in a big twitter thread, https://twitter.com/profanegeometry/status/1202751074752327680 06-Dec-19 06:04 PM Bremsstrahlung sunburn? 06-Dec-19 06:04 PM i definitely assumed the worst from the outset 06-Dec-19 06:04 PM that was my guess from the very earliest news reports 06-Dec-19 06:04 PM You'd have to be VERY persistent to get sunburn from anything but UV out of a fusor 06-Dec-19 06:04 PM i meant 'sunburn' as more of a euphemism for x-ray burns, in fairness, but, yeah 06-Dec-19 06:04 PM . o O (i still want a fused quartz viewport though) 06-Dec-19 06:05 PM I can always post some spoilered pictures of what actually happens when a moron kid plays with x-rays 06-Dec-19 06:05 PM i would prefer if you did not 06-Dec-19 06:05 PM glad we share that opinion 06-Dec-19 06:05 PM I never said you could take my picture 06-Dec-19 06:06 PM oh no you're at least doing it the redneck safety way 06-Dec-19 06:06 PM that kid just straight up ignored all safety 06-Dec-19 06:06 PM Well I do live in the south :P 06-Dec-19 06:06 PM and dive a turbo diesel 06-Dec-19 09:04 PM Florida Man, checking in 06-Dec-19 10:41 PM @Treehouseman wait, I too drive a turbo diesel... Does this put me into some sort of category??? 06-Dec-19 10:41 PM was looking up how to enable coal rolling a few weeks ago, for those pesky people who tailgate dangerously 06-Dec-19 10:43 PM I think yours is the least redneck turbo diesel ever 06-Dec-19 10:43 PM Lol 06-Dec-19 10:43 PM By a lot 06-Dec-19 10:43 PM I mean 06-Dec-19 10:43 PM It's a rabbit right? 06-Dec-19 10:43 PM It is a piece of fine german engineering 06-Dec-19 10:43 PM Jetta actually, about 2 or 3 decades newer than the rabbit 06-Dec-19 10:44 PM Oh something new? 06-Dec-19 10:44 PM Although they might have brought back that model in the past 5 or 10 years 06-Dec-19 10:44 PM Nah, the same one I think you rode in once 06-Dec-19 10:44 PM Ok yeah 06-Dec-19 10:44 PM Fine German engineering is not how you described it to me 06-Dec-19 10:45 PM Hahah, "it works" 06-Dec-19 10:45 PM On the scientifically illiterate society causing legal grief for home experimentors... There's a lot of biology stuff that really has fired up the hate machine in the past 06-Dec-19 10:45 PM Even so much as to get university professors all messed up 06-Dec-19 10:45 PM https://en.wikipedia.org/wiki/Steve_Kurtz 06-Dec-19 10:45 PM I've actually been invited by the FBI a few times to attend meet and greets about DIYbio stuff 06-Dec-19 10:45 PM Basically they're like, "uh, self police your community please, and don't break zoning laws" 06-Dec-19 10:45 PM https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5278613/ 06-Dec-19 11:12 PM wow i had never heard about that guy's story. pretty crazy that they tried to charge him just for ordering nonpathogenic bacteria samples 06-Dec-19 11:12 PM also...the DIYbio community has some great parts and some really sketchy parts haha but they do actually do a decent job policing themselves so far from what i have seen 06-Dec-19 11:12 PM bit too much testing their creations on themselves for my taste though 06-Dec-19 11:12 PM https://www.youtube.com/watch?v=YVvY0fSP7u8 06-Dec-19 11:12 PM Anyone recognize the source container? Seems like a green cylinder w/ a flip top lid. 06-Dec-19 11:12 PM They tried to sell it for €3 million haha https://www.europol.europa.eu/newsroom/news/crime-group-suspected-of-smuggling-nuclear-materials-arrested-in-vienna 06-Dec-19 11:21 PM that's freakin' scary on the Kurtz story 06-Dec-19 11:21 PM my friends give me a hard time for not sharing my projects on FB but I know if I did I'd wind up arrested because dumb ppl 06-Dec-19 11:27 PM reading that pubmed paper... not sure about this assertion but i do not want to unfairly cast aspersions on anywhere/anyone "Alexander Murer, founder of OLGA—Open Biolab Graz, the Austrian biohackerspace—was also skeptical: “There is no relation or connection whatsoever between terrorism and biohacking. Biohacking evolved around community labs (biohackerspaces), which can't be used for illegal activities due to their openness." 06-Dec-19 11:27 PM the "can't be used for illegal activities due to their openness" part of the statement is what i have an issue with, to be clear, not the "no relation or connection whatsoever between terrorism and biohacking". that part is totally accurate 06-Dec-19 11:40 PM @LRM it would be pretty hard in the biohacker spaces, just due to the amount of lab time and things like ordering certain chemicals that would likely only be shippable to a non-resdiential address 06-Dec-19 11:40 PM There was at least one instance I barely remember, I think in either biocurious (sunnyvale CA) or genspace (Brooklyn NY) 06-Dec-19 11:40 PM Anyway the person was just generally acting shady, wouldn't talk about what they were doing, so they got kicked out 06-Dec-19 11:42 PM Yeah the only stuff I have heard about were fairly harmless (but still illegal) side projects 06-Dec-19 11:43 PM There's been a lot of talk about letting your local fire chief know you're doing funky hobbies, in case you ever need to call an ambulance or the fire trucks, etc... 06-Dec-19 11:43 PM But I've not done that, I've really only got high voltage at home aside from some biotech stuff thats mostly shelved project materials and equipment 06-Dec-19 11:44 PM That seems like something to keep in reserve for if you are doing medium or larger scale ewaste processing and other chemistry stuff 06-Dec-19 11:45 PM There's a lab like 5 mins from my house in an industrial park, and they have no problem keeping fuming nitric and HF... So I've just been planning to do anything dangerous there since "it's zoned industrial!!!" 06-Dec-19 11:45 PM Nice 06-Dec-19 11:46 PM Not a hackerspace, but a place that i work at part time and are pretty open to my bio/nano tech ideas 06-Dec-19 11:46 PM The illegal stuff i have heard about going on in biohacker spaces is all suuuuper pedestrian by the way...like people culturing erm special fungi heh 06-Dec-19 11:46 PM Which is kinda too easy to even need a hackerspace for 06-Dec-19 11:47 PM Yeah the people doing it were mainly there doing sequencing work 06-Dec-19 11:47 PM Well DNA and spores are totally legit ;) 06-Dec-19 11:47 PM Not in California! Even if they grow here? 06-Dec-19 11:47 PM Frowned upon maybe... 06-Dec-19 11:47 PM Makes no sense to me 06-Dec-19 11:48 PM Well they're decriminalized in Oakland now...so CA IDK 06-Dec-19 11:48 PM Ahh forgot about Oakland 06-Dec-19 11:48 PM Anyway, this isn't radiation talk I guess 06-Dec-19 11:49 PM True heh 06-Dec-19 11:49 PM Still want to know what the green tube source is 06-Dec-19 11:53 PM @qualia aren't we all quantum physics generators? 07-Dec-19 05:37 AM @nmz787 2003 jetta sportwagen here :P 07-Dec-19 10:21 AM I hate how co2 lasers get ridiculously expensive as you drop below 40W 07-Dec-19 10:22 AM bee....low? 07-Dec-19 10:23 AM or otherwise phrased "I hate how you can't modulate beam power linearly" 07-Dec-19 10:23 AM just get an nLight light-in-a-box dingus from eBay 07-Dec-19 10:23 AM they're anywhere from $100 to $900 depending on power 07-Dec-19 10:23 AM don't think that'll handle glass 07-Dec-19 10:23 AM you may have a point 07-Dec-19 10:25 AM working on a glass fiber processing system and at 40w millisecond pulses I'm still getting periodic features 07-Dec-19 10:25 AM and I don't have any idea off hand on doing an aperture mask with a defocused beam or similar 07-Dec-19 10:25 AM perhaps a beam splitter and then just dump the other half 07-Dec-19 10:25 AM score https://www.aliexpress.com/item/32609282252.html 07-Dec-19 10:25 AM I really want a 5watt little helium neon sized cutesy guy 07-Dec-19 10:48 AM @Deleted User any chance you recognize that green cylindrical source container in that video from EUROPOL? sorta from your general area of the world and it was not one that i have ever seen before 07-Dec-19 10:49 AM let's see 07-Dec-19 10:49 AM nope, not that I know of 07-Dec-19 10:49 AM looks old and painted over 07-Dec-19 10:49 AM it looks like a thermos to me lol 07-Dec-19 10:53 AM haha well that is unfortunate 07-Dec-19 10:53 AM wonder what they had in it that they were trying to sell for 3million 07-Dec-19 10:53 AM well given the size of container and relatively low dose rates... a scam? 07-Dec-19 10:53 AM unless it's something like plutonium 07-Dec-19 12:02 PM @Metanoic show me! 07-Dec-19 12:02 PM though excimer might not work for me at all 07-Dec-19 08:30 PM sry gotta sit on this one for a bit 07-Dec-19 08:37 PM hehe 07-Dec-19 11:22 PM sorta random question but anyone know what some of the more commonly used personal dosimeters are in research/commercial settings? 07-Dec-19 11:25 PM in germany every worker in a radiation environment has to wear an official film dosimeter which gets exchanges monthly and checked by the Landesamt für Umwelt 07-Dec-19 11:25 PM in addition, i have seen fisher scientific dosimeters (for the real settings) or old used military surplus dosimeters (if your boss is an idiot) 07-Dec-19 11:31 PM I probably should have specified electronic personal dosimeters i have seen the fischer sci stuff used before too 07-Dec-19 11:31 PM just looking to get an idea of what gets a significant market share 07-Dec-19 11:32 PM yep 07-Dec-19 11:32 PM oh, and i have seen the tracerco in use. specifically i used one. 07-Dec-19 11:34 PM ahhh those i have seen in use before i think 07-Dec-19 11:34 PM when i tried checking out google there is way too much noise to signal ratio lol 07-Dec-19 11:35 PM yes 09-Dec-19 06:30 AM I wonder if anyone has repurposed an argon ion laser as a focused ion beam source.. obv the optics won't help, but they're cheap these days and run in the 10kv range and has the pre-kicker surge for dielectric breakdown and several amps.. could be interesting 09-Dec-19 06:32 AM the 10 kV are just for ignition, burning voltage is ~110V 09-Dec-19 06:32 AM oh is that right 09-Dec-19 06:32 AM at least for the alc 60x it is 09-Dec-19 06:32 AM and I don't think they differ that much from model to model 09-Dec-19 06:34 AM well poo, wonder still what the power supply could sustain continuous 09-Dec-19 06:34 AM will do some reading 09-Dec-19 06:34 AM thanks for the info to narrow my scope 10-Dec-19 07:47 PM https://i.imgur.com/t8viTAv.jpg 11-Dec-19 07:40 AM I wanna see a picture of this death box Cs source. 11-Dec-19 09:02 AM I agree 11-Dec-19 02:59 PM same 12-Dec-19 01:13 AM you'll probably only see snowstorm on that picture... :-D 14-Dec-19 06:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191214_100058-16F58.jpg 14-Dec-19 06:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191214_100106-2D754.jpg 14-Dec-19 06:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191214_141556-8D5DC.jpg 14-Dec-19 06:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191214_141604-5041B.jpg 14-Dec-19 06:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191214_145034-18D7D.jpg 14-Dec-19 06:37 AM I found a device for measuring activity of radioactive devices at the scrapyard <3 14-Dec-19 06:50 AM Blue thing totally looks like a water bottle cap. 14-Dec-19 09:11 AM your scrapyard has ridiculously interesting stuff 14-Dec-19 11:05 AM Yep, I totally love that place 14-Dec-19 11:05 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191214_194030-08D0D.jpg 14-Dec-19 11:05 AM my room is starting to look quite cozy 14-Dec-19 11:05 AM Tho I really want a nim minibin for the readout electronics 14-Dec-19 11:05 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/4006-59859.png 14-Dec-19 11:12 AM what sort of a scrapyard is it that they get so much high end science/industrial tech 14-Dec-19 11:12 AM only ones i have ever been to are mostly car parts, consumer junk, and a tiny slice of industrial mystery components 14-Dec-19 11:12 AM nothing ever that seems even half usable heh 14-Dec-19 11:14 AM most of the stuff is just scrap 14-Dec-19 11:14 AM lotsa car parts, but sometimes, just sometimes... 14-Dec-19 11:14 AM ok tbh it's getting a bit rediculous recently 14-Dec-19 11:16 AM i think most of the places here are savvy enough to list that stuff on eBay at the very least 14-Dec-19 11:17 AM ah, our laws really hinder that 14-Dec-19 11:17 AM something about warranty and stuff 14-Dec-19 11:21 AM interesting 14-Dec-19 11:21 AM in the USA if you sell it as-is you generally are good to go from the sellers point of view 14-Dec-19 11:28 AM here you have to sell it as broken or provide 1 y of warranty 14-Dec-19 11:28 AM and for some reason no one wants to sell it as broken, as there is some hassle involved as well 14-Dec-19 05:36 PM aww that nim minibin is so adorable 14-Dec-19 06:35 PM wow that's a heck of a scintillator 14-Dec-19 06:35 PM i assume it's more counting-grade than spectroscopy-grade 14-Dec-19 11:40 PM They usually are, but I could not find any information on it regarding that 14-Dec-19 11:40 PM Talk to Scionix! 14-Dec-19 11:40 PM They'll help. 15-Dec-19 12:06 AM yeah, I should really hit them up, got another couple of scintillators I need info to 26-Dec-19 03:30 PM any suggestions on a geiger counter for some experiments or things to look out for? 26-Dec-19 03:36 PM What are you looking to measure? 26-Dec-19 03:36 PM If you're looking for a generic and relatively sensitive meter, I recommend grabbing a Ludlum Model 3(any) with a 44-9 pancake probe 26-Dec-19 03:36 PM They're all over eBay, make sure to hunt around for a great deal 26-Dec-19 03:36 PM man, have they shot up in price 26-Dec-19 03:40 PM i'd like to alter transistor/capacitor state via ionizing particles in several ways, some radioactive material or possibly other devices. i'd like to make sure i'm staying safe and handling things properly 26-Dec-19 03:40 PM See if this will ship to you 26-Dec-19 03:40 PM https://www.ebay.com/itm/Dosimeter-Model-3100-Survey-Meter-with-Bicron-GI-LE-Probe/323743224389 26-Dec-19 03:40 PM The meter is... well, I have no idea what that thing even is 26-Dec-19 03:40 PM but the G1LE probe is wonderful 26-Dec-19 03:40 PM here's a nice unit as well 26-Dec-19 03:40 PM https://www.ebay.com/itm/Ludlum-3-Geiger-Counter-Survey-Meter/302522318570 26-Dec-19 03:40 PM but comes with no probe 26-Dec-19 03:40 PM (the G1LE is compatible) 26-Dec-19 03:42 PM Shipping:May not ship to Germany - Read item description or contact seller for shipping options. | See details 26-Dec-19 03:42 PM shoo skwirel 26-Dec-19 03:42 PM everyone deserves a good meter :D 26-Dec-19 03:43 PM lol, that's a bit much for a m3 in that condition... 26-Dec-19 03:43 PM dude the prices went up so much 26-Dec-19 03:43 PM got a lot of m12 in similar conditions for about half that 26-Dec-19 03:43 PM sell him one if you have a spare 26-Dec-19 03:43 PM ludlum m12s are even more expensive on ebay 26-Dec-19 03:44 PM there's one seller 26-Dec-19 03:44 PM one sec 26-Dec-19 03:44 PM also 26-Dec-19 03:44 PM https://www.ebay.com/itm/Ludlum-43-4-Alpha-radiation-detectors-12-available/143400451612? 26-Dec-19 03:44 PM RECOIL 26-Dec-19 03:44 PM oh wait those are $50 each 26-Dec-19 03:44 PM not $50 for 12 26-Dec-19 03:45 PM hahahahaha 26-Dec-19 03:45 PM https://www.ebay.com/usr/daveshepard 26-Dec-19 03:45 PM doesn't look like he has much for sale 26-Dec-19 03:45 PM https://www.ebay.com/itm/283699524946 26-Dec-19 03:46 PM perfect for bathroom tiles 26-Dec-19 03:46 PM @samy in short: Ludlum Model 3, 12, 14, 14c, and others, are generic "counter boxes" 26-Dec-19 03:46 PM They provide an adjustable high voltage power supply and an integrator that will tell you how many pulses you have per minute 26-Dec-19 03:46 PM You can attach many different probes 26-Dec-19 03:47 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191212_193043-2AE50.jpg 26-Dec-19 03:47 PM I gotta say I really like that seller 26-Dec-19 03:48 PM The G1LE I linked is a very thin, scintillator probe with a low energy, thin crystal and an even thinner foil window. It's great for detecting low levels of radiation, but it's very nonlinear, and nearly blind at high energies. 26-Dec-19 03:48 PM The Ludlum 44-9 probe is a regular geiger-muller tube, except in pancake form with a very thin mica or beryllium window 26-Dec-19 03:48 PM ok cool 26-Dec-19 03:48 PM Great for detecting all sorts of radiation, nearly blind to very low energies, but quite linear and goes quite high up for radioactive isotopes 26-Dec-19 03:48 PM nah the 44-2 is NaI 26-Dec-19 03:48 PM is it? 26-Dec-19 03:48 PM oh wait, 44-9 26-Dec-19 03:49 PM 44-9... 26-Dec-19 03:49 PM yes 26-Dec-19 03:49 PM my bad 26-Dec-19 03:49 PM My suggestion is to get a Model 3 with a 44-9 probe to start 26-Dec-19 03:49 PM If you can get it for a good price 26-Dec-19 03:49 PM They're universal and there's a reason they survived through decades, and are still made today 26-Dec-19 03:51 PM or try to get a model 12 26-Dec-19 03:51 PM seriously ask that seller I posed above 26-Dec-19 03:51 PM or wait until he posts one of his ludlum offers again 26-Dec-19 03:51 PM go through his completed listings 26-Dec-19 03:55 PM ooh 26-Dec-19 03:55 PM https://www.ebay.com/itm/Bicron-Surveyor-M-Radiation-Countrate-Meter/303258410778? 26-Dec-19 03:55 PM this is a great option! 26-Dec-19 03:55 PM @GigaSquirrel you might want one too if you're not drowning in survey meters 26-Dec-19 03:56 PM ok cool 26-Dec-19 03:57 PM this must be a serious information overload for you lol 26-Dec-19 03:57 PM this is great 26-Dec-19 03:57 PM the surveyor m is a great option 26-Dec-19 03:57 PM grab that, and look for a 44-9 probe 26-Dec-19 03:58 PM What sort of radiation source would you be working with 26-Dec-19 03:58 PM For what he wants to do - altering silicon, I'm going to say an x-ray source is needed 26-Dec-19 03:58 PM well I'm not drowning in bicron ratemeters 26-Dec-19 03:58 PM if you want to stay sane and alive anyway 26-Dec-19 03:58 PM @GigaSquirrel bicrons are so neat 26-Dec-19 03:58 PM I have an Analyst 26-Dec-19 03:58 PM same thing, except no digital scaler, but has an energy discriminator 26-Dec-19 03:59 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191227_005920-E1A72.jpg 26-Dec-19 03:59 PM I know, but so far I just didn't get my hands on one, I think you can see a trend 26-Dec-19 04:00 PM Looks like you have a ludlum infestation 26-Dec-19 04:00 PM might want to spray some detectorcide 26-Dec-19 04:00 PM nooo not my detectors / ratemeters 26-Dec-19 04:00 PM if I got my hands on a m16 / 18 I would not need so many 26-Dec-19 04:01 PM I want an eberline e600 26-Dec-19 04:01 PM but since I didn't... 26-Dec-19 04:01 PM My only concern with x-rays is you’re going to have a hard(er) time getting any sense of dose rate information off a GM detector 26-Dec-19 04:01 PM a 44-9 will tell you if you have leaks 26-Dec-19 04:01 PM if it suddenly goes quiet you should generally run 26-Dec-19 04:02 PM True, I guess I’m coming from a different background but I’d be looking for an ion chamber based meter 26-Dec-19 04:02 PM the G1LE linked earlier(mislabeled as GILE) is the detector for x-rays 26-Dec-19 04:02 PM thin NaI:Tl disk with a foil window 26-Dec-19 04:02 PM I've tested it to sniff out x-rays at just a few keV and all the way up to a few hundred keV with some difficulty 26-Dec-19 04:02 PM hard to beat this: 26-Dec-19 04:02 PM https://www.youtube.com/watch?v=kGERXzl84sk& 26-Dec-19 04:02 PM (G1LE in question) 26-Dec-19 04:02 PM Th-232, so mostly alphas and some x-rays 26-Dec-19 04:04 PM And if your question is a yes or no, that sounds way superior and more reliable 26-Dec-19 04:04 PM well, a GM probe is still good for "yes or no" 26-Dec-19 04:04 PM it's just that the G1LE is a little less versatile, and it still costs money 26-Dec-19 04:05 PM Fair 26-Dec-19 04:06 PM spectacular probe for x-ray work though 26-Dec-19 04:07 PM I was thinking reliable compared to say this: https://www.ebay.com/itm/Bicron-RSO-5-Radiation-Survey-Meter-/303383157709 26-Dec-19 04:07 PM see, that will tell you "no" when you should be in the "run" state 26-Dec-19 04:07 PM that's got an internal detector, I'd go for something that takes external 26-Dec-19 04:07 PM it will tell you a precise "no" 26-Dec-19 04:07 PM but it's going to be way too late 26-Dec-19 04:09 PM would uranium oxide from Fiestaware be able to alter state within silicon or alter small amounts of capacitance? 26-Dec-19 04:09 PM Not on the low range, 1mR/hr isn’t going to hurt you particularly fast (the low range of the meter) 26-Dec-19 04:09 PM not in any noticeable way @samy 26-Dec-19 04:09 PM ok 26-Dec-19 04:09 PM you will want an x-ray source 26-Dec-19 04:09 PM a dental head and a bunch of lead, ideally 26-Dec-19 04:09 PM if you have a basement it's even better 26-Dec-19 04:10 PM Seconding that, you’ll need a fairly large dose 26-Dec-19 04:11 PM i see -- ultimately I'd just like to flip a bit in SRAM 26-Dec-19 04:11 PM And there’s no way to get a source that large without an obscene amount of money and licensing 26-Dec-19 04:11 PM yeah, except x-rays 26-Dec-19 04:11 PM though that... kinda... still... needs licensing... cough 26-Dec-19 04:11 PM but at least you can flip a switch and make it inert 26-Dec-19 04:13 PM I stand corrected 26-Dec-19 04:13 PM hm? 26-Dec-19 04:15 PM On the licensing bit 26-Dec-19 04:16 PM it's generally less painful, but if you aren't licensed you also won't get raided by three letter agencies 26-Dec-19 04:16 PM whereas owning a few unlicensed curies of something is going to cause immediate panic 26-Dec-19 04:17 PM Few unlicensed millicuries more like 26-Dec-19 04:18 PM that just slightly reduces the level of panic and number of bullets 26-Dec-19 04:21 PM Some days I wish I could find something like this: https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2019/20191129en.html 26-Dec-19 04:21 PM The second item 26-Dec-19 04:21 PM Most days I have more sense though 26-Dec-19 04:23 PM 544uCi, ouch 26-Dec-19 04:29 PM I’ve handled much much worse but not outside of work 26-Dec-19 04:36 PM i don't want huge sources i want small amounts of weird isotopes 26-Dec-19 04:36 PM don't we all 26-Dec-19 04:36 PM i don't understand the appeal of having enormous amounts of radioactive material 26-Dec-19 04:36 PM just like as a thing to collect 26-Dec-19 04:36 PM i mean i guess i do, it just seems silly 26-Dec-19 04:37 PM @samy iv got access to a variety of sources if there's something specific you want to expose 26-Dec-19 04:43 PM @AdamMcCombs ahh awesome. i'm working on a cloud chamber right now to at least visualize and starting to read up on this to see what's necessary to potentially trigger a momentary state change in silicon or capacitance/electric field 26-Dec-19 04:43 PM When your device is exposed to a high enough amount it's going to start causing latchups 26-Dec-19 04:43 PM Looking at using it for glitching? 26-Dec-19 04:44 PM What you could try doing is placing an Am-241 puck directly on the die 26-Dec-19 04:44 PM That's safe and doesn't really require a counter 26-Dec-19 04:44 PM Downside is that you may be waiting for a while 26-Dec-19 04:45 PM @AdamMcCombs nah just messing around -- i'd like to just reproduce a single upset event 26-Dec-19 04:45 PM Then you probably want an Am-241 puck 26-Dec-19 04:45 PM it outputs high energy gammas, but rarely 26-Dec-19 04:45 PM i see 26-Dec-19 04:45 PM and you can buy one cheap in any hardware store :P 26-Dec-19 04:46 PM i'd like the counter just to make sure i'm not dying 26-Dec-19 04:46 PM then grab the bicron and find a pancake probe 26-Dec-19 04:46 PM k 26-Dec-19 04:46 PM when you get the pancake you'll need to adjust the high voltage to match the pancake supply voltage 26-Dec-19 04:49 PM And potentially make sure the count rate displayed matches the real one with some degree of accuracy. 26-Dec-19 04:49 PM But honestly, that step is probably overkill if you leave the audio on. 26-Dec-19 04:51 PM if it's a working probe and the voltage is set correctly, it's going to work 26-Dec-19 11:18 PM Oh darn, @samy you are kamkar... Lol. I am also from PGH 26-Dec-19 11:19 PM @nmz787 ah nice -- haven't been back since i left ~15...socal has been too sunny, but would be fun to check out again! 26-Dec-19 11:19 PM Yeah it's not that great aside from the pretzel shop in south side, mike and tonys gyros, primanti's sandwiches 26-Dec-19 11:19 PM I left at 18 myself, but have been back a bunch, never for too long tho 26-Dec-19 11:29 PM ahh 27-Dec-19 11:42 PM I don't remember seeing this channel on my last visit. Perhaps I should be paying more attention as a health physicist and LSO. 27-Dec-19 11:43 PM Ah yeah more safety fun times 27-Dec-19 11:55 PM So, Am-241 from the hardware store... 1) Smoke detectors for the last decade have been made with laser sensors, not Am-241. 2) The Am-241 sources a decade ago are considerably weaker than the were 20 years ago. 3) In the US, Am-241 is under a General License from the NRC for the smoke detectors. This means it approved for this particular configuration & usage AND ONLY THAT. The moment you crack it open, you better be operating under a rad license that lets you possess and work with transuranics or you just bought yourself a very large fine. 27-Dec-19 11:55 PM In short, DON'T DO THAT. 27-Dec-19 11:55 PM You can buy Am-241 sealed sources from Eckert & Ziegler which let you get away with a much more limited license, but you still need one. 28-Dec-19 12:01 AM So, 1) Yes, except the US. Can still pick them up easily there. 2) Definitely, but that's a plus. The standard is now 0.1uCi, though a few have been reported to be within +100-300% of that, lol 3) Aren't these ultra low activity sources exempt from the minimum limit? 28-Dec-19 12:01 AM You can also buy sealed test sources with all kinds of isotopes from United Nuclear, for example. 28-Dec-19 12:02 AM Ah, yes. United Nuclear. You'll note that Am-241 isn't in their source set. 28-Dec-19 12:03 AM Because it's a bit of an impractical source of alphas 28-Dec-19 12:04 AM No, because it is transuranic and we don't license that willy nilly. 28-Dec-19 12:04 AM Something something legal ambiguity 28-Dec-19 12:04 AM But I agree, in the US there's plenty of easier and legal ways to get much hotter and at the same time safer sources 28-Dec-19 12:04 AM Not so much elsewhere 28-Dec-19 12:05 AM It isn't ambiguous at all. NRC is very clear and picky about TRU. Other nations are even less friendly. And no, the Am-241 that used to be in smoke detectors we not tiny sources. There is no such thing as exempt for TRU. 28-Dec-19 12:05 AM Generally Licensed is VERY SPECIFIC in definition under the NRC. 28-Dec-19 12:05 AM That used to be, yes 28-Dec-19 12:05 AM Nowadays they're tiny 28-Dec-19 12:05 AM Though smoke detectors with up to 30mCi of Am-241 or Pu-mix do pop up on ebay sometimes 28-Dec-19 12:05 AM You'd be insane to buy one, given their age 28-Dec-19 12:07 AM Sale of which is patently illegal as is possession without a license if they aren't in their original Generally Licensed smoke detector form. Sorry, this is my damn job. 28-Dec-19 12:08 AM You'd be insane to buy one, you'd have to be completely braindead to actually open it up 28-Dec-19 12:08 AM But they're sold as smoke detectors, in their original form 28-Dec-19 12:08 AM eBay doesn't take too kindly to nuclear materials trafficking lol 28-Dec-19 12:10 AM They don't control worth a crap, any more than Amazon, or Aliexpress. Have absolutely seen and reported bare 5mCi Am-241 sources stripped out of old smoke detectors. 28-Dec-19 12:10 AM Well, yeah, they can't review thousands of listings per minute 28-Dec-19 12:10 AM But it gets you banned, and for good reason 28-Dec-19 12:10 AM Hence my job security. 28-Dec-19 12:11 AM I use an Am-241 tablet(in its housing, sorta kinda inside the detector) when I need to test an alpha detector 28-Dec-19 12:11 AM And everyone who can have access to it knows not to touch it under any circumstances 28-Dec-19 12:12 AM What you have just described is a violation of the NRC General License. 28-Dec-19 12:12 AM Good thing I'm on the other end of the world! 28-Dec-19 12:12 AM If I was in the US I'd just get a license for a nice set of source pucks 28-Dec-19 12:13 AM Australia is decidedly not more friendly 28-Dec-19 12:13 AM Not that end 28-Dec-19 12:13 AM The wrong end 28-Dec-19 12:13 AM UK/EU is worse. 28-Dec-19 12:13 AM Belarus 28-Dec-19 12:13 AM Where nnnnnnnnnobody cares 28-Dec-19 12:13 AM (and it's within the minimum limits) 28-Dec-19 12:14 AM Well, there are some people who care, but they are underpaid and few in number. 28-Dec-19 12:14 AM We can own a bunch of stuff so long as it's in the low-kBq range 28-Dec-19 12:14 AM And I haven't had a need for more than that 28-Dec-19 12:14 AM The rules are on the books as more or less IAEA default, but with almost no one to enforce them. 28-Dec-19 12:15 AM I'm aware, I compiled all the rules into a nice spreadsheet for myself as reference 28-Dec-19 12:15 AM I also have family members directly responsible for some fun nuclear things, though on paper 28-Dec-19 12:16 AM Welp, happy irradiating to you! 28-Dec-19 12:17 AM I prefer detecting 28-Dec-19 12:19 AM @funranium if you want to be extra disappointed in eBay/aliexpress check out the Am241 "Ion Chamber" listings which include a bit saying "Add a nice "hot" piece to your collection which emits alpha and gamma radiation." 28-Dec-19 12:19 AM Are you talking about the HIS-01 ion chambers from the ionization detectors? 28-Dec-19 12:20 AM https://www.aliexpress.com/i/32927767859.html 28-Dec-19 12:20 AM Yup... those 28-Dec-19 12:20 AM TO BE FAIR 28-Dec-19 12:20 AM Ionization chamber smoke detectors are still the best 28-Dec-19 12:20 AM You have to go very high end in the smoke detector selection to get performance comparable to a cheap ion chamber 28-Dec-19 12:21 AM I have them in my house, they last forever as long as you keep dust out of them 28-Dec-19 12:21 AM And they're very sensitive 28-Dec-19 12:21 AM @funranium how would one go about safely/responsibly disposing of an Am-241 button source if they've already popped one out before they knew it was a legal problem? 28-Dec-19 12:21 AM like, they're technically supposed to be sent back to the manufacturer at the end of their life, right? 28-Dec-19 12:21 AM but people throw them in the trash all the time 28-Dec-19 12:22 AM Ship to: Landfill, China 28-Dec-19 12:23 AM brb founding a neptunium recovery startup 28-Dec-19 12:29 AM Yes, people throw them in the trash all the time because they don't read instructions. Not the ones on the box or the smoke detector itself. Household hazardous waste is good starting place. You can also contact Kidde (the likely manufacturer of your smoke detector to see how they'd like it returned). Depending on your jurisdiction, your local fire station may have a collection drum. 28-Dec-19 12:29 AM @LRM it is hard to make me more disappointed in ebay/Amazon/Aliexpress 28-Dec-19 12:29 AM Calling the fire station(non emergency number) is usually a good idea for disposal of anything hazmat because if they can't do it, they know who can 28-Dec-19 12:29 AM Pretty much anywhere in the world 28-Dec-19 12:30 AM oh, maybe i'll walk down there and say hello sometime 28-Dec-19 12:37 AM been meaning to pester them to see if i need any kind of permit or whatever to practice firedancing in my backyard also 28-Dec-19 12:37 AM since it's right adjacent to a park 28-Dec-19 12:37 AM and they might like to know about that in advance 28-Dec-19 12:18 PM Heh, gona make a good first impression. Asking about radioactive source disposal and firedancing. 28-Dec-19 02:29 PM heh just don't be like the person who put a bunch of radium 226 in a gallon bag in the trash, and when the trash truck drove by a PAPER MILL it set off one of their radiation alarms 30-Dec-19 11:21 AM Anyone familiar with the square bicron/saint-gobain/who knows scintillator probes? 30-Dec-19 11:22 AM raises hand 30-Dec-19 11:23 AM Just trying to get an idea of what they’re like inside the housing before I open one up so I don’t accidentally destroy it 30-Dec-19 11:23 AM Particularly is the crystal otherwise encapsulated beyond the outer casing. 30-Dec-19 11:24 AM They have raw crystals inside them, bonded to the scintillator, and then filled with epoxy up to around 1/10th of the scintillator housing 30-Dec-19 11:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191230_202328-49F38.jpg 30-Dec-19 11:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20191230_202401-F3CBB.jpg 30-Dec-19 11:24 AM Yep 30-Dec-19 11:24 AM if you need any detail pics just ask ^^ 30-Dec-19 11:24 AM It's not encapsulated at all 30-Dec-19 11:24 AM Just the bare crystal stuffed into the housing and backfilled with epoxy 30-Dec-19 11:25 AM no, the crystal is encapsulated in there 30-Dec-19 11:25 AM got its own little housing with the pmt glued onto it 30-Dec-19 11:25 AM Not in mine 30-Dec-19 11:25 AM I have 2 and both are bare crystals inside the outer housing, with an epoxy shield 30-Dec-19 11:26 AM well, my two are built like the one above 30-Dec-19 11:26 AM I believe the ones marked "bicron" are repurposed alpha spectra scints 30-Dec-19 11:26 AM Alpha spectra scints were hung in the hundreds on trucks 30-Dec-19 11:27 AM Well then I’m probably not going to risk it just yet 30-Dec-19 11:27 AM Thanks 30-Dec-19 11:28 AM If your meter drives it, don't pull it apart 30-Dec-19 11:28 AM If it can't, the back cap is sealed in and is somewhat removeable 30-Dec-19 11:32 AM Yeah, I noticed the back cap looked like it could potentially be removed but then realized that if I screwed it up I’d be left with a pmt and a mess 30-Dec-19 11:33 AM best to do it in a dry atmosphere 30-Dec-19 11:33 AM just in case 30-Dec-19 11:33 AM but the pmt section shouldn't be sensitive to moisture 30-Dec-19 02:29 PM Forgot I had this cute little thing 30-Dec-19 02:29 PM https://i.gyazo.com/adc749891bf2545f3ba0f4df500dc50c.png 30-Dec-19 06:42 PM <__ice9#6039> https://www.sciencedirect.com/science/article/pii/S1738573318304819 Apparently there is a much simpler method to make thorium tetrafluoride than attacking the oxide with hot anhydrous HF or (rather futilely) attempting to dissolve it in HNO3 mixed with HF (as I did, with little success): just grind up the oxide with about 5.5 molar equivalents of ammonium bifluoride and... let it sit in a (plastic) test tube for about a week. Then bake the resulting intermediate at about 450C in a quartz tube with a light flow of argon flush gas to yield the tetrafluoride. That can in turn be converted into the metal. 30-Dec-19 06:42 PM <__ice9#6039> The tetrafluoride can be reduced to the metal relatively easily as per the attached (other reading suggests elevated pressure is not needed; an oversized crucible with a heavy lid should be sufficient), or by other similar processes documented in the literature via analogous single replacement reactions using comparable reactive metals 30-Dec-19 06:42 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1577760334649-CA097.png 30-Dec-19 06:42 PM <__ice9#6039> The resulting thorium metal can be used to seed a skull crucible melt of monocrystalline thorium dioxide, as demonstrated e.g. here-- https://digital.library.unt.edu/ark:/67531/metadc1061426/ 30-Dec-19 06:42 PM <__ice9#6039> ... thus resolving the somewhat mediocre thermal shock sensitivity of the sintered material by contrast, making it more suitable for super high temperature furnace and torch components subjected to oxidizing conditions 30-Dec-19 06:42 PM <__ice9#6039> Obviously hot HF still comes out the end of the quartz tube, along with flammable hydrogen gas, so best to do that stage outdoors-- with a bubbler tube into a plastic container if you want to try to recapture some of the HF for later use. HF is a very useful horribly toxic corrosive acid, thoria (thorium dioxide) is an alpha emitter usually provided or extracted as a hazardous respirable powder, ammonium bifluoride is basically a solid storable HF source, and in general this process involves processing radioactive poisonous chemicals. But in a nicer way than usual. Proper equipment, protective devices, and relevant experience necessary. Supposedly this same process also works on uranium dioxide (not sure about other oxides), but that isn't as useful for my interest in high temperature ceramics. 30-Dec-19 06:42 PM <__ice9#6039> See also: https://agedspoonchemistry.blogspot.com/2016/05/thorium-dioxide-from-electrodes.html?m=1 Thorium dioxide is also available on eBay and Alibaba 30-Dec-19 06:42 PM <__ice9#6039> It does require an NRC general license in most forms, and the license in question requires holding an interest in a business entity, fwiw 30-Dec-19 07:11 PM have any info about the use in ceramics? not something i really have any knowledge of but it sounds interesting 30-Dec-19 07:14 PM <__ice9#6039> Dental x-ray heads usually require something like a 25kHz push-pull inverter to drive them, using idk 900V+ IGBTs at 400V driving voltage and some very carefully designed snubbers-- just fwiw. Line frequency x-ray transformers are quite large and heavy by comparison, though simpler. For lower-voltage applications, old Soviet tubes if in good enough condition can instead just be driven by sufficiently well filtered flyback transformer output, which is probably easier than driving the dental ones in all honesty. Though often the Russian tubes have poor vacuum quality and may have short lifespans before arcing-- I once saw someone drill one out to pump it down externally instead in order to revive it. I digress. 30-Dec-19 07:14 PM <__ice9#6039> Yes. Thorium oxide has the highest melting point of any oxide ceramic. It is completely stable in air to over 3000 C 30-Dec-19 07:14 PM <__ice9#6039> As an additive to tungsten, it also makes imo by far the best quality TIG welding electrodes-- they hold a point better than any others I have tried and do not suffer from oxide migration issues etc; they tolerate accidental abuse better as well, e.g. bumping into the melt. 30-Dec-19 07:14 PM <__ice9#6039> Thoria also has much lower electrical conductivity than yttria stabilized zirconia or calcia stabilized zirconia-- so if you want to try making a furnace using electrically conductive ceramic elements, it can be used to prevent the current from being diverted through the walls 30-Dec-19 07:14 PM <__ice9#6039> As a potentially respirable alpha emitter, it is important to use a good quality respirator when processing the powder or any fragments of sintered material. Other than that, it is relatively inert. As noted, it is difficult to even dissolve it in HNO3+HF. 30-Dec-19 07:22 PM yes my only experience with thorium is that it is in most of the granite where i go hiking sometimes, in some welding electrodes, and in one magnesium thorium alloy part a friend gave me (he works on helicopters) 30-Dec-19 07:22 PM oh and lantern mantles when i was a kid 30-Dec-19 07:22 PM that is very interesting re: 3000C ceramic 30-Dec-19 07:25 PM <__ice9#6039> Yeah it glows a sort of pale blue when very strongly heated. Mantles are heavily doped with cerium oxide to impart a vivid white light output instead. 30-Dec-19 07:28 PM The only downside to using thoriated tungsten electrodes is, you know 30-Dec-19 07:28 PM Finely powdered radioactive dust thrown across your workshop every time you touch the electrode by accident and have to re-grind it 30-Dec-19 07:28 PM <__ice9#6039> I didn't know about use of the metal as an additive in magnesium alloys. It looks like Mag-Thor also often contains some zirconium. The major oxide ceramics fwiw are basically alumina, magnesia-stabilized zirconia, calcia-stabilized zirconia, yttria-stabilized zirconia, ceria, yttria, a few other rare earth oxides, and thoria. Magnesia and calcia in their pure forms are also in occasional use, but they suffer greatly from atmospheric moisture-- converting into useless and friable hydroxide scales at the surface. 30-Dec-19 07:31 PM the dust from thoriated electrodes isnt so bad afaik mostly because it is alloyed with tungsten and it is pretty heavy 30-Dec-19 07:31 PM so it does not stay in the air much at all 30-Dec-19 07:31 PM it's not alloyed 30-Dec-19 07:31 PM it's in ThO2 form in the electrodes 30-Dec-19 07:31 PM dissolving the tungsten yields ThO2 with no chemical conversion 30-Dec-19 07:33 PM interesting, did not know that 30-Dec-19 07:33 PM <__ice9#6039> Hmm debatable. 1) use a supplied air respirator whenever you weld, especially stainless; manganese fumes cause parkinsonism and I don't even want to talk about hex chrome, nevermind any minuscule hazard from the electrode, 2) there isn't going to be any dust on it once it has been heated once, 3) the main dust risk is during grinding and yes you should do that with a mask and collecting container, arguably for any electrode type, 4) numerous studies have found quite low radiation exposure from thoriated tungsten among even full-time welders, much less hobbyists using supplied air systems. 30-Dec-19 07:33 PM <__ice9#6039> But yeah that's correct, it's not an alloy 30-Dec-19 07:33 PM when you weld doesn't matter really 30-Dec-19 07:33 PM <__ice9#6039> It's more of a cermet 30-Dec-19 07:33 PM there's a big piece of plastic deflecting all the nasties 30-Dec-19 07:33 PM but thoria dust floating around your shop is a total no-go 30-Dec-19 07:33 PM you need a wet grinder and a wet collector, runoff from which should be treated as hazmat 30-Dec-19 07:34 PM everyone i know who uses them just has a shop vac by the grinder lol but they are welders and those are not known for their safety consciousness 30-Dec-19 07:34 PM <__ice9#6039> Addressed in 3 30-Dec-19 07:34 PM way too many downsides to tho2 30-Dec-19 07:34 PM <__ice9#6039> Disagree; Zr blues are inferior 30-Dec-19 07:34 PM <__ice9#6039> Esp @ high current 30-Dec-19 07:34 PM <__ice9#6039> Purples only marginally better 30-Dec-19 07:35 PM I prefer a lack of thorium dust floating around 30-Dec-19 07:35 PM <__ice9#6039> Addressed in 3 ^^ 30-Dec-19 07:35 PM let's face it: nobody is going to use 3 :P 30-Dec-19 07:35 PM <__ice9#6039> Idk I do 30-Dec-19 07:35 PM to be fair: you are here. 30-Dec-19 07:37 PM <__ice9#6039> Hmm anyway-- pure thoria powder is much more hazardous until fused or sintered. Important to keep in mind if experimenting with ceramics. 30-Dec-19 07:38 PM not something i plan to experiment with, just interesting to learn that it is capable of such high temps 30-Dec-19 07:38 PM I kinda want to make a ThO2 puck out of my welding electrode packs 30-Dec-19 07:38 PM but they're safe the way they are 30-Dec-19 07:39 PM <__ice9#6039> Lol it can be done, but it's probably cheaper to just buy from that eBay seller splitting up a kg or two they bought on Alibaba 30-Dec-19 07:39 PM <__ice9#6039> Presumably originally produced for making those electrodes, mainly 30-Dec-19 07:40 PM Importing ThO2 in ThO2 form would likely get me... in trouble, while actually owning it is fine. Our legal system is funny like that. 30-Dec-19 07:40 PM Not to mention, the customs question:" "You tried to buy WHAT!?" 30-Dec-19 07:40 PM i imagine importing that to the USA gets you on all the fun lists 30-Dec-19 07:41 PM <__ice9#6039> Weird. Here it's totally fine to import but ownership requires some minor recordskeeping. 30-Dec-19 07:41 PM It's not like it's a big issue, it's freely available in the country as welding electrodes 30-Dec-19 07:41 PM Go into a shop and ask for "big red ones" 30-Dec-19 07:41 PM not suggesting anything negative would happen at all, just you will probably get a bit extra scrutiny 30-Dec-19 07:42 PM <__ice9#6039> I think in practice there is a limit of about 7kg of DU and some similar amount of ThO2 at any given time, depending on the particulars, but it's such a specialized material I can't imagine ever using that much. It's also about $400/kg 30-Dec-19 07:42 PM Funny that it's $400/kg 30-Dec-19 07:42 PM given that it's mostly useless 30-Dec-19 07:42 PM nobody wants it and it's a byproduct 30-Dec-19 07:42 PM still kicking myself for not buying a chunk of DU when it was all over ebay just to have it to point at 30-Dec-19 07:42 PM but probably for the best 30-Dec-19 07:43 PM <__ice9#6039> Reds have quite a devoted following among welders who do a lot of high current DC work 30-Dec-19 07:43 PM <__ice9#6039> DU is so expensive... it's like $10-20/gram everywhere. I have a little bit available, but only a few grams. For the longest time I was looking for a DU APFSDS dart, but it was just impossible-- the only ones that made it into private hands at all have mostly gone to very well connected munitions collectors and veterans 30-Dec-19 07:46 PM for awhile (2008-2012?) there were decent sized (1/2" thick and 1" x 1" or 1" x 2") blocks of it on eBay for around $100-200 30-Dec-19 07:46 PM then a couple years after that some 1/2" and 3/4" rods 30-Dec-19 07:47 PM <__ice9#6039> ... impressive. I was seeing quarter-sized pieces for $500+ and couldn't justify that. Will have to wait until someone has a sketchy sliced up counterweight or similar I imagine. 30-Dec-19 07:47 PM yeah i have no idea what the source was of it which was part of why i never bought any 30-Dec-19 07:47 PM the rods seemed like they might have been scrap from penetrating round manufacture 30-Dec-19 07:47 PM like prototyping or something 30-Dec-19 07:47 PM had lathe tool marks on the ends 30-Dec-19 07:48 PM <__ice9#6039> Almost certainly sliced up counterweights in the ones I saw, judging by the angular prismatic or plate like shapes, and yeah that sounds like munitions 30-Dec-19 07:48 PM <__ice9#6039> Probably 30mm cannon API rounds 30-Dec-19 07:48 PM <__ice9#6039> I don't have much of an actual physical use for DU though. Thoria is extremely useful for casting and coating refractory metals, making cermets, making high temperature ceramics, etc, plus it's just cool to actually perform some of the steps in proposed fuel cycles to prepare it. DU is of more sentimental value. 30-Dec-19 07:48 PM <__ice9#6039> UxO shows up in some ceramic glazes, but the various oxidation states are much more complex and varied than for thorium, plus melting at 2860C is barely better than yttria-stabilized zirconia 30-Dec-19 07:48 PM <__ice9#6039> Actually crystal structure stability and oxidative stability are major issues in high temperature ceramics -- zirconia is pretty much only usable over an extended temperature range because it can be stabilized by calcia/magnesia/yttria/(scandia/ceria/... expensive but very cool ceramic solid oxide fuel cell dopants) 31-Dec-19 03:22 AM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/straka2017-ECAB0.pdf 01-Jan-20 08:47 AM Do you need any powder form ThO2 ? Small amounts can be sold and shipped. I have a decent size legacy supply found in materials that were left to me. 01-Jan-20 08:47 AM It’s just sitting I’m my lead box in the garage nowadays. 02-Jan-20 03:28 AM <__ice9#6039> Interesting. I have a lot of it currently. I will keep this in mind if I somehow manage to use it all, but for the foreseeable future that's probably unlikely 02-Jan-20 04:02 AM <__ice9#6039> The solid state reaction may be working. It's changed color and become stickier. Continuing to shake it up and recompact it daily. Should be ready to pyrolyze in a few days. 06-Jan-20 04:22 AM seriously, why do manufacturers not specify the gas gain for their proportional detectors 06-Jan-20 11:38 AM hey so, EDS was just mentioned someplace 06-Jan-20 11:38 AM is an EDS detector just a small/thin-active-region low-energy X-ray HPGe detector? 06-Jan-20 11:38 AM i keep seeing ~cheap ones on ebay, sometimes on vacuum flanges, and i'm wondering if one might be worth playing with at some point for trying to pick up characteristic x-rays from e.g. hot plasmas 06-Jan-20 11:38 AM not sure if that'd totally swamp it out 06-Jan-20 11:41 AM hrmmm I mean generally its to pick up Xrays off pretty low energy stuff thrown off 30~kv electrons being thrown at stuff in an SEM 06-Jan-20 11:41 AM you use SDDs for EDS, they're silicon drift detectors with a bit weird geometry 06-Jan-20 11:42 AM and yea the windows are THIN 06-Jan-20 11:42 AM leme get some photos from my broken one... 06-Jan-20 11:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/2532-89981.png 06-Jan-20 11:42 AM they can handle quite high counting rates, k to m per second 06-Jan-20 11:43 AM https://photos.app.goo.gl/3F9ZVmC4wFHDBwqV8 06-Jan-20 11:43 AM ᵗʰᶦⁿ 06-Jan-20 11:43 AM that's generally the failure mode of these things... 06-Jan-20 11:43 AM just as a fore-warning of cheap ones on eBay... 06-Jan-20 11:44 AM ah hm 06-Jan-20 11:44 AM if they can get a photo of the tip that's the best 06-Jan-20 11:44 AM and making sure they know to keep that safe... 06-Jan-20 11:44 AM I need to bite the bullet and get the new like 400-600 dollar window for mine 06-Jan-20 11:46 AM oof 06-Jan-20 11:46 AM just make sure you get the preamp with it, because the signal from those is tiny 06-Jan-20 11:46 AM 46 fC per MeV, and we're talking about the single keV range 06-Jan-20 11:48 AM I would assume most of these have some kind of pre-amp built into the head itself??? 06-Jan-20 11:48 AM the one i was looking at definitely had a preamp builtin 06-Jan-20 11:48 AM I mean or does that actually stay as a good signal over 12 feet of coax? 06-Jan-20 11:48 AM they do, but often times people take them out 06-Jan-20 11:48 AM oh I guess if they tear it apart 06-Jan-20 11:48 AM that should be fairly obvious then 06-Jan-20 11:49 AM that signal would definitely not coherently survive a length of coax 06-Jan-20 11:49 AM iirc capacitance between the detector and preamp is also a hugely important factor 06-Jan-20 11:50 AM yep, the capacitance is the major contribution to noise 06-Jan-20 11:50 AM test 06-Jan-20 11:51 AM ping hello 06-Jan-20 11:51 AM lagged a bunch 06-Jan-20 11:51 AM ah, and I thought it was me 06-Jan-20 11:52 AM anyways, i think the sort of detector i want is actually more in the EUV range, for light-ion recombination spectra 06-Jan-20 11:52 AM EDS seems like it's not too useful for things lighter than sodium 06-Jan-20 11:52 AM (... but i still kinda want one) 06-Jan-20 11:53 AM I mean what you need is an SEM with an EDS on it. 06-Jan-20 11:53 AM Like the second one sitting in my basement doing nothing. 06-Jan-20 11:53 AM i wish i had the room for a SEM 06-Jan-20 11:53 AM i don't even have a regular optical microscope 06-Jan-20 11:54 AM this one is just the size of a standard desk honestly 06-Jan-20 11:54 AM like its not that horrible 06-Jan-20 11:54 AM it just has no wheels... 06-Jan-20 11:54 AM ... 06-Jan-20 11:54 AM that's out of the question 06-Jan-20 11:54 AM and the feet aren't tall enough to get a pallet jack under it 06-Jan-20 11:54 AM THANKS AMRAY, I HATE IT 06-Jan-20 11:55 AM do the egyptian thing and roll it up onto some successively larger dowels 06-Jan-20 11:55 AM @qualia just move to NY where the taxes are just as high but you have more space and less commute (depending on where you work) 06-Jan-20 11:55 AM then roll it into my backyard 06-Jan-20 11:55 AM lol thats kinda what happened to get it moved 06-Jan-20 11:55 AM nice thing though is 06-Jan-20 11:55 AM its 120V 06-Jan-20 11:55 AM man i was born & raised in NY i don't really wanna go back if i can help it 06-Jan-20 11:55 AM NYC or NY State? 06-Jan-20 11:56 AM state 06-Jan-20 11:56 AM honestly I kinda like where I am in NY state... 06-Jan-20 11:56 AM western new york-ish 06-Jan-20 11:56 AM oh... 06-Jan-20 11:56 AM yea aka middle of nowhere? 06-Jan-20 11:56 AM i mean yeah 06-Jan-20 11:56 AM yea no thanks lol 06-Jan-20 11:56 AM I'm north of NYC about 1:30 hours 06-Jan-20 11:56 AM so we still have stuff around, tech stuff, and well 06-Jan-20 11:56 AM all the ewaste of NJ, NY,MA... 06-Jan-20 11:56 AM delicious :9 06-Jan-20 11:56 AM good supply of stuff 06-Jan-20 11:56 AM If your ever out this way your welcome to visit :) 06-Jan-20 11:56 AM I'm like 3 miles from the train station, hudson river line, same one billy joel sings about 06-Jan-20 11:56 AM lmao 06-Jan-20 11:56 AM I just thought 06-Jan-20 11:56 AM What's Adam's favorite artist? Billy Jeol 06-Jan-20 11:58 AM snrk 06-Jan-20 11:58 AM budumtis 06-Jan-20 11:58 AM XD 06-Jan-20 11:58 AM @AdamMcCombs here you can see my horrible joke 06-Jan-20 01:08 PM Went up to the lab to mess around with EDS mapping 06-Jan-20 01:08 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/JPEG_20200106_160750-139A1.jpg 06-Jan-20 01:08 PM This is not with an SDD, just an older Si(Li) detector that needs the LN2 06-Jan-20 01:08 PM I was just told this JOEL JSM-840 SEM I'm using may be up for sale when I graduate 06-Jan-20 01:08 PM The count rate here is actually limited by the dead time of the pulse processing circuits, and it really has no problem at all with resolution and statistics as long as you're a bit patient with it 06-Jan-20 01:15 PM right, I forgot about Si(Li) 06-Jan-20 01:15 PM never worked with them, do they need constant cooling like Ge(Li) or can they survive when warm? 06-Jan-20 01:16 PM They can survive being warm 06-Jan-20 01:16 PM But not recommended 06-Jan-20 01:16 PM Now, the FWHM required to resolve peaks like this is on the order of 1 keV, maybe a bit less. This should be achievable with a thermoelectrically cooled PIN diode with a good preamp 06-Jan-20 01:16 PM Build your own EDS anyone? 06-Jan-20 01:16 PM It will probably be pretty bad in resolution, but useful for at least some common elements 06-Jan-20 01:29 PM I'm not sure about achieving 1 keV fwhm with a regular pin diode 06-Jan-20 02:43 PM It's possible, but it will be quite difficult 06-Jan-20 02:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/sipin6mm2-13DBE.png 06-Jan-20 02:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/detectormechanical-3995B.png 06-Jan-20 02:43 PM Also, for EDS mapping work, you don't necessarily need the super narrow FWHM peaks 06-Jan-20 02:48 PM @Conmega lol 06-Jan-20 02:49 PM It depends on what you want to identify, if there're two element emission peaks several keV away, you can easily bin them manually and still get a pretty good idea of elemental distributions on your sample 06-Jan-20 02:49 PM No quantitative work is really possible here (can't get accurate % measurements), but hey, it'll be a lot cheaper and a lot simpler 06-Jan-20 02:49 PM The key here is a pretty thick intrinsic layer of silicon, really low noise charge-sensitive preamp and probably quite a bit of patience 06-Jan-20 11:10 PM maybe we're not talking about the same thing, sdds are also just PIN devices and can achieve <100 eV, but I thought you suggested using regular pin diodes for optical detection, like the bpw34 and alike 06-Jan-20 11:24 PM When I say PIN diodes I do mean the simplest kind like Hamamatsu S3590 and bpw34, the one Amptek uses is nothing special neither 06-Jan-20 11:24 PM It's just that very careful design is required, active cooling is a must and the preamplifier likely needs to be right next to it as well 06-Jan-20 11:24 PM https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930003978.pdf 06-Jan-20 11:26 PM oh, interesting! 06-Jan-20 11:27 PM BPW34 is not the ideal choice here 06-Jan-20 11:27 PM I've always been told the pin devices for x-ray detection differ from optical ones, they have a way smaller doped / passivated region on the "input" side 06-Jan-20 11:27 PM Yeah that's it 06-Jan-20 11:27 PM that's the main limit for Resolution 06-Jan-20 11:27 PM (assuming an ideal preamp) 06-Jan-20 11:28 PM But Hamamatsu makes special large area PIN diodes specifically for x-ray detection, the S3590 is the prime example, used with or without scintillators 06-Jan-20 11:29 PM ah, now I get it 06-Jan-20 11:29 PM next issue for diy will be the preamp 06-Jan-20 11:29 PM gotta collect some fC to aC 06-Jan-20 11:32 PM https://ieeexplore-ieee-org.libproxy.rpi.edu/document/504173?arnumber=504173&SID=EBSCO:edseee 06-Jan-20 11:32 PM This is at room temperature 06-Jan-20 11:32 PM https://www.cremat.com/CR-111-R2.1.pdf 06-Jan-20 11:37 PM but is it really diy if you take a diode made for the application and solder it onto a readymade preamp? :P 06-Jan-20 11:38 PM Oh yeah you can certainly design and make your own preamp 06-Jan-20 11:38 PM It's possible to get better noise performance, it will be harder and more expensive of course. 06-Jan-20 11:38 PM https://www.amazon.com/CR-110-R2-Charge-Sensitive-preamplifier-Module/dp/B079VG3KXY 06-Jan-20 11:38 PM There's something to be said for throwing something together really quickly though, these preamps are not that expensive 06-Jan-20 11:38 PM There're also other parts here that needs more DIY, the MCA for example and pulse processing electronics is not at all trivial. 06-Jan-20 11:38 PM And then there's synchronization with the e-beam rastering 06-Jan-20 11:41 PM it doesn't Show me a price for the preamp, only that it can't deliver to my location 06-Jan-20 11:41 PM It's $55 for me with free shipping 06-Jan-20 11:42 PM oh 06-Jan-20 11:42 PM yeah that's a good price 07-Jan-20 12:06 AM Cremats are very overpriced for what they are inside 07-Jan-20 12:06 AM But "what they are inside" is about $waytoomany components that need lots of LTSPICE'ing to get right 07-Jan-20 12:06 AM (and I do mean probably LT specific) 07-Jan-20 12:06 AM However they are a nice solution for a thing that you just plug in and it works 07-Jan-20 12:06 AM No hassle 07-Jan-20 12:08 AM That's the attractive part yeah, I'd like to try and make something myself with JFETs being quite affordable now 08-Jan-20 04:41 AM is there any good open source multichannel analyser designs around? tried that theremino thing but it didn't seem to work that well. my detector is a XP2202 with a NaI(Tl) crystal strapped to it. 08-Jan-20 04:48 AM theremino needs a lot of pulseshaping to work properly, that's the hard part 08-Jan-20 04:48 AM and by properly I mean "kindasorta" 08-Jan-20 04:48 AM yeah, and my power supply is not too clean 08-Jan-20 04:48 AM that's gonna ruin your Resolution before anything else 08-Jan-20 04:48 AM but the ripple is very periodic and somewhat small compared to pulses, so DSPing it away should be easy 08-Jan-20 04:48 AM the actual pulses from this thing are huge when viewed directly on my TDS5104 oscilloscope 08-Jan-20 04:48 AM but haven't been able to get a reasonable spectrum of any of the sources i have access to yet. 08-Jan-20 04:50 AM what color is your NaI? 08-Jan-20 04:51 AM mostly clear, some discoloration around the edges of the module 08-Jan-20 04:51 AM and can you post a pic of your setup? 08-Jan-20 05:01 AM cant find any pictures of the full setup but i can take one of the detector as it is right now, keep in mind that this is very much a learn-as-i-go project 08-Jan-20 05:01 AM https://revspace.nl/kiekjes/view/20200108/P1010111.JPG the detector (not the most useful picture because of the shielding obscuring most of it from view) 08-Jan-20 05:01 AM https://revspace.nl/kiekjes/view/20200108/P1010113.JPG - the divider (values of resistors were tested and match the "best linearity" divider in the datasheet) 08-Jan-20 05:08 AM did you shield it any further? 08-Jan-20 05:08 AM wasn't too necessary with the sources i was using. 08-Jan-20 05:08 AM no, electrically 08-Jan-20 05:09 AM yes. had a soldered shut pcb can around it 08-Jan-20 05:09 AM but after i last tested it i started building an actual case for it and its still in the middle of that project. all cables were rg58 08-Jan-20 05:23 AM some pulses (background, dont have a source atm): lots of these: https://revspace.nl/kiekjes/view/20200108/P1010118.JPG 08-Jan-20 05:23 AM once every minute or so a big one like this happens: https://revspace.nl/kiekjes/view/20200108/P1010119.JPG 08-Jan-20 05:25 AM congrats, you built a cosmic ray detector 08-Jan-20 05:25 AM looks fine, albeit a bit slow 08-Jan-20 05:25 AM and far from the bipolar pulse theremino wants to see 08-Jan-20 05:26 AM also on the big ones, it looks to me as if the pulse is cut off by power supply limits 08-Jan-20 05:26 AM the shape is just so very different to the somewhat 1-exp(t) shape of the small ones 08-Jan-20 10:07 AM @pbx/peterbjornx any specific resources that got you started? 08-Jan-20 10:43 AM @pbx/peterbjornx looks like your pulses are a bit too long 08-Jan-20 10:43 AM Are you able to get a spectrum at all? 08-Jan-20 10:43 AM If you are and it looks very "smooth" and with little definition that means your amplifier/pulse shaper is way too slow and your sampling shouldn't matter much 08-Jan-20 10:43 AM @Goldsteel knows how to fix bad detector outputs and why they happen 08-Jan-20 10:43 AM @samy what are you interested in specifically? 08-Jan-20 11:08 AM ^the current results (with a better scope) 08-Jan-20 11:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-B41CD.jpg 08-Jan-20 11:08 AM ^ using my scope's histogram function to get the spectrum of a radium watch hand 08-Jan-20 11:08 AM green is based on "area" but only has some 28k counts yet, the yellow one is 130k counts over 2k bins based on minimum voltage for the pulse 08-Jan-20 11:15 AM well you're not going to get much of a radium spectrum 08-Jan-20 11:15 AM but it looks like you're getting pretty much what you need 08-Jan-20 11:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/7184786882_d814a476a8_b-F7B34.png 08-Jan-20 11:15 AM Your spectrum is a bit smooshed, probably a drop in energy response somewhere or a slow amp 08-Jan-20 11:15 AM But you're pretty much seeing that 08-Jan-20 11:15 AM except... in reverse 08-Jan-20 11:15 AM https://i.spirit.re/o2MjU.jpg 08-Jan-20 11:43 AM why was i summoned 08-Jan-20 11:43 AM i am busy 08-Jan-20 11:43 AM fine have it your way 08-Jan-20 11:43 AM elaborate drivel 08-Jan-20 11:43 AM @Deleted User thats a PZ error on the amp, its why its tailing 08-Jan-20 11:43 AM massive overshoot 08-Jan-20 11:46 AM There you go :P 08-Jan-20 11:46 AM @GigaSquirrel although people often claim an uncalibrated system is a cosmic detector, its often not the case unless you set your threshhold to above 1.6MeV or so 08-Jan-20 11:46 AM the ambient environment is constant contaminated by the 1460 potassium line 08-Jan-20 11:47 AM which he did in a way, if you see "waiting for a big signal" is a form of triggering 08-Jan-20 11:47 AM i mean yeah 08-Jan-20 11:47 AM thats my point 08-Jan-20 11:47 AM but if his preamp cant go that high 08-Jan-20 11:47 AM he might just plateu 08-Jan-20 11:47 AM hence, he may ONLY be seeing the potassium lines and mistaking them for cosmics 08-Jan-20 11:47 AM ghetto solution: 08-Jan-20 11:47 AM youll only get cosmics through a lead castle 08-Jan-20 11:47 AM discriminate the lead scatters 08-Jan-20 11:47 AM now we're cooking with gas 08-Jan-20 11:49 AM to be honest I wasn't 100 serious about the cosmic ray thing 08-Jan-20 11:49 AM also today i convinced people to spent 250 thousand pounds on stuff i need @Deleted User 08-Jan-20 11:49 AM Finally got that NIM budget? 08-Jan-20 11:49 AM more, bigger chunks of Ge? 08-Jan-20 11:49 AM i have the NIM stuff, just not good stuff 08-Jan-20 11:49 AM the crystals cost $$$$$ 08-Jan-20 11:49 AM biggerer is gooderer 08-Jan-20 11:49 AM the crystals the goodest bit 08-Jan-20 11:50 AM that photo with a gaylord full of NIMs gave me a few conniptions 08-Jan-20 11:50 AM a lot of my equipment is hand-me-down post-soviet bullpoopy 08-Jan-20 11:50 AM but whatever i can make do 08-Jan-20 11:50 AM @Goldsteel pictures are always welcome 08-Jan-20 11:50 AM oh 08-Jan-20 11:50 AM sure 08-Jan-20 11:50 AM 1s 08-Jan-20 11:50 AM its my dindin time but ill send a few pics 08-Jan-20 11:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-904FD.jpg 08-Jan-20 11:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-5C49B.jpg 08-Jan-20 11:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image2-DAAEF.jpg 08-Jan-20 11:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-1C2B6.jpg 08-Jan-20 11:52 AM ohh pop top 08-Jan-20 11:52 AM Oh, so the MMRs are used for cooling detectors? 08-Jan-20 11:52 AM I thought they were rated to around -70C 08-Jan-20 11:53 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-F4CCA.jpg 08-Jan-20 11:53 AM no 08-Jan-20 11:53 AM "What kind of radiation?" Yes. 08-Jan-20 11:53 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-47774.png 08-Jan-20 11:53 AM mines idle at -163.1C 08-Jan-20 11:53 AM right now 08-Jan-20 11:53 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-925FA.jpg 08-Jan-20 11:53 AM ayyy I think I have some of the same modules 08-Jan-20 11:54 AM this is what a MAN sees 08-Jan-20 11:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-A79E9.jpg 08-Jan-20 11:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-F4A64.jpg 08-Jan-20 11:54 AM wait 08-Jan-20 11:54 AM not that one 08-Jan-20 11:54 AM Oh so the x-cooler is fed by ln2 08-Jan-20 11:54 AM it's not one of those self-contained ones 08-Jan-20 11:55 AM brb 08-Jan-20 11:58 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200108_205458-95E68.jpg 08-Jan-20 11:58 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200108_205506-E78E5.jpg 08-Jan-20 11:58 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200108_205538-E965C.jpg 08-Jan-20 11:58 AM some more nim posting to pass the time until goldsteel is back XD 08-Jan-20 12:17 PM i am back 08-Jan-20 12:17 PM yeah ive got hundreds of all this stuff just hanging around in shelves in the lab space 08-Jan-20 12:17 PM nobody uses them so i can daisy chain what i like together to do signal shaping, delays and scopes in various positions 08-Jan-20 12:17 PM cheap scopes are fine if they show the signal well enough 08-Jan-20 12:19 PM which is whar nim is great for 08-Jan-20 12:19 PM readout electronics lego 08-Jan-20 12:19 PM which reminds me, I started a very interesting repair project today 08-Jan-20 12:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200108_155906-C9566.jpg 08-Jan-20 12:19 PM all signs point to bad Vacuum, but amp sill intact 08-Jan-20 12:22 PM babby dewer 08-Jan-20 12:22 PM shows microphonics, but the crystal doesn't go below -70 08-Jan-20 12:22 PM baby dewar and only 2 keV fwhm, probably worse considering its condition 08-Jan-20 12:22 PM but tbh if I get below 8 keV I'll be happy 08-Jan-20 12:23 PM 2 is expected for Ge 08-Jan-20 12:23 PM 2 is spec 08-Jan-20 12:24 PM im ~2 at about 1MeV 08-Jan-20 12:24 PM really? 08-Jan-20 12:24 PM yes 08-Jan-20 12:24 PM I'd have expected better from your stuff, at least 1.8 08-Jan-20 12:25 PM 1.75 at 778.9 08-Jan-20 12:25 PM it can go lower if you abuse it enough 08-Jan-20 12:25 PM best I've seen so far war 1.4 at 1.33 iirc? 08-Jan-20 12:25 PM ~1 is normal at low energy 08-Jan-20 12:25 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8A602.png 08-Jan-20 12:25 PM 0.97keV FWHM on 121.78keV 08-Jan-20 12:25 PM ive got it down to 0.6 once 08-Jan-20 12:27 PM I want HPGe detectors that work at TEC temps 08-Jan-20 12:27 PM and the software once reported 0.3 08-Jan-20 12:27 PM but i dont believe it 08-Jan-20 12:27 PM so -60 for a tiny witty bitty crystal 08-Jan-20 12:27 PM with a TEC pyramid behind it 08-Jan-20 12:28 PM so basically you're looking for CZT 08-Jan-20 12:28 PM .3 and .6 at what energy tho? 08-Jan-20 12:30 PM .3 was just xrays 08-Jan-20 12:30 PM .6 was the 121 08-Jan-20 12:30 PM i dont remember what i did 08-Jan-20 12:30 PM it may also have been a software error trying to fit all the gaussian with 2 bins 08-Jan-20 12:30 PM but in general 1 is expected for what i have at low energy 08-Jan-20 12:30 PM 2 for everything else 08-Jan-20 12:30 PM oh and 08-Jan-20 12:30 PM im going to murder mine with fast neutrons 08-Jan-20 12:30 PM sorry lads its going to become slag 08-Jan-20 12:30 PM whats the dead gauges society 08-Jan-20 12:35 PM just bake it, as long as it isn't so strongly activated it swamps out signal you'll only loose some resolution in the lower end 08-Jan-20 12:35 PM theres only so much you can do with annealing 08-Jan-20 12:35 PM this isnt crystal damage 08-Jan-20 12:35 PM this is nuclear transitions 08-Jan-20 12:35 PM its highly likely it will be a lump of inert poop after its been through the oven a few times 08-Jan-20 12:36 PM but until then 08-Jan-20 12:36 PM and if you scrap them I'll gladly take then 08-Jan-20 12:37 PM until then its a cool dude whos ready to smell gammas 08-Jan-20 12:37 PM theyre not mine 08-Jan-20 12:37 PM theyre the property of the united states government as of... 12 hours ago 08-Jan-20 12:37 PM once they're trash of the united states government we'll take one each :P 08-Jan-20 12:38 PM they also make for some nice room decoration 08-Jan-20 12:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200108_213728-3D2EB.jpg 08-Jan-20 12:38 PM i mean sure id sell you them 08-Jan-20 12:38 PM i dont need them 08-Jan-20 12:38 PM (to be fair that was a Ge(Li), not a HPGe) 08-Jan-20 12:38 PM is it a "lump of inert poop" in terms of actual detection 08-Jan-20 12:38 PM or is it still going to see with a fwhm of a few kev? 08-Jan-20 12:38 PM id sell people more crap but my lab wont let it reclaim scrap, we have to only claim what we have used and sell it to specific waste handlers 08-Jan-20 12:38 PM just... a lot higher than regular? 08-Jan-20 12:39 PM i dunno yet spirit 08-Jan-20 12:39 PM ill tell you though 08-Jan-20 12:39 PM also here's a trick 08-Jan-20 12:39 PM pick a waste handler you sell to 08-Jan-20 12:39 PM and talk to them 08-Jan-20 12:39 PM talking bad 08-Jan-20 12:39 PM no like 08-Jan-20 12:39 PM "look I'll sell it to you and then I'll buy it back privately for 10% more" 08-Jan-20 12:39 PM no handling needed, pure profit for them 08-Jan-20 12:42 PM we'll see 08-Jan-20 12:42 PM we have issues rn with brexit stuff 08-Jan-20 12:42 PM a bunch of phd STFC funding just went down the toilet 08-Jan-20 12:42 PM we cant afford to bring on more students and so theyll need sponsors now and GTA 08-Jan-20 01:12 PM watch hand spectrum, log plot of hist(min(C2)) on my LeCroy6030A. 08-Jan-20 01:12 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DA6FC.png 08-Jan-20 01:14 PM yeah that actually looks pretty decent 08-Jan-20 01:14 PM i'm amazed at the ease with which the software on that scope can be used as a makeshift MCA 08-Jan-20 01:14 PM was doing some 300-400 counts per second easily, with software oversampling for 3 extra bits of resolution 08-Jan-20 01:21 PM @Deleted User building a cosmic ray detector or high energy particle detector would be cool 08-Jan-20 01:21 PM all detectors do that 08-Jan-20 01:21 PM lmao 08-Jan-20 01:21 PM its harder to make a cosmic veto 08-Jan-20 01:21 PM could build a coincidence detector for cosmic rays 08-Jan-20 01:21 PM i guess 08-Jan-20 01:22 PM i built a liquid cooled peltier cloud chamber recently but would be fun to play around more there 08-Jan-20 01:22 PM You gotta make videos about all this :P 08-Jan-20 01:22 PM pics or didnt happen!!! 08-Jan-20 01:23 PM i plan to, but i want the videos to correlate with security projects that i'm working on in tandem 08-Jan-20 01:23 PM cloud security 08-Jan-20 01:23 PM haha 08-Jan-20 01:23 PM the cloud chamber is related to a security project and the sputtering is another project 08-Jan-20 01:23 PM how is any of this a security risk 08-Jan-20 01:23 PM what 08-Jan-20 01:23 PM i have videos of cloud chambers 08-Jan-20 01:24 PM I'm going to guess random upset events 08-Jan-20 01:24 PM i mean, they're fun on they're own, but i like the vid to be sec related 08-Jan-20 01:24 PM and sputtering for... readout protection? 08-Jan-20 01:26 PM @Deleted User exactly (upset events) -- the sputtering is for a transparent "USB condom" since most of the existing ones don't show what's inside, which is a risk in itself, so i believe if using one you should see that there's nothing but power lines going through...except the data lines might still run through via ITO with one data line wired to an ITO antenna 08-Jan-20 01:26 PM that is a very clever idea 08-Jan-20 01:26 PM i made a prototype from ITO plastic but it sucks 08-Jan-20 01:26 PM i mean, it just looks awful 08-Jan-20 01:26 PM i have a box of old coincidence detector frontends from the hisparc programme 08-Jan-20 01:26 PM sputtering ITO is going to be hard 08-Jan-20 01:26 PM so i rather mask and sputter 08-Jan-20 01:27 PM but it's doable at "home" 08-Jan-20 01:27 PM as Ben Krasnow proved 08-Jan-20 01:27 PM what makes it specifically hard? 08-Jan-20 01:27 PM modeling upset events is best done with either a high energy gamma/alpha source or an x-ray source as for ITO sputtering, #general 08-Jan-20 01:31 PM as for upset events, i've always been surprised at airport xray machines not crashing computers moving through them 08-Jan-20 01:31 PM at some point i turned on my phones camera before putting it in the tray and it went white with snow, but no data corruption or segfaults as far as i could tell 08-Jan-20 01:36 PM the dose rate is relatively low and the exposure is brief 08-Jan-20 01:58 PM hmm, but still funny how its easily able to trigger the camera pixels, but not dram cells 08-Jan-20 02:12 PM because camera pixels are large area photodiodes :P 08-Jan-20 02:13 PM And are designed to be charge sensitive 08-Jan-20 02:14 PM fair enough, but shouldn't a silicon photodiode be pretty much deaf to high energy photons? 08-Jan-20 02:14 PM at regular intensities, yes 08-Jan-20 02:14 PM but with x-rays, you're generating a good flashlight level of photons 08-Jan-20 02:14 PM chance takes over 08-Jan-20 02:15 PM right. still though, drams have also been used as cameras and generally have much smaller charge per element than a normal camera sensor afaik 08-Jan-20 02:17 PM yeah, there's a DRAM camera project that made an image 08-Jan-20 02:17 PM a very dull image 08-Jan-20 02:17 PM given that you only have 1 bit resolution :P 08-Jan-20 02:17 PM Well they use time for the bit to flip as an additional measurement of light intensity 09-Jan-20 04:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200109_132445-25733.jpg 09-Jan-20 04:31 AM yay new detector 09-Jan-20 05:20 AM As requested 09-Jan-20 05:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-D86A2.jpg 09-Jan-20 05:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-A07A6.jpg 09-Jan-20 05:21 AM https://media.tenor.com/images/d84e4d88a85b16ad5b49bee467be49f1/tenor.gif 09-Jan-20 06:49 AM As requested @Goldsteel 09-Jan-20 06:49 AM They kinda look like synth modules 09-Jan-20 06:52 AM but they're sth way better 09-Jan-20 06:57 AM that something is.......? 09-Jan-20 06:58 AM NIM! 09-Jan-20 06:58 AM NIM du zuerst 09-Jan-20 06:58 AM https://en.wikipedia.org/wiki/Nuclear_Instrumentation_Module that? 09-Jan-20 06:59 AM that! 09-Jan-20 07:00 AM Yes 09-Jan-20 07:00 AM They’re designed for daisy chain signal processing 09-Jan-20 07:00 AM but the ones in the pictures are not a standard, they´re devices 09-Jan-20 07:00 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/SO8VK6U-E866C.png 09-Jan-20 07:00 AM They’re designed for daisy chain signal processing @Goldsteel signals coming from detectors? 09-Jan-20 07:03 AM Yes commonly 09-Jan-20 11:31 AM https://twitter.com/profanegeometry/status/1215345495746367488 speaking of new detectors.. glad i didn't drop $$$ on a random ebay EDX detector.. these just fell into my lap >.> 09-Jan-20 11:31 AM i have done zero research into these and hafta go to work instead and i'm annoyed about it 09-Jan-20 11:35 AM dang you made some real scores 09-Jan-20 11:35 AM where did that stuff come from? 09-Jan-20 11:37 AM fell off the back of a truck 09-Jan-20 11:37 AM :D 09-Jan-20 11:37 AM friend of friends was cleaning out his attic/garage 09-Jan-20 11:38 AM Wow nice! 09-Jan-20 11:38 AM nice 09-Jan-20 11:43 AM oh wow, congrats! 09-Jan-20 11:44 AM Umm I've got to ask for one of those EDS detectors as well 09-Jan-20 11:44 AM Don't know where to find a window for it since most of the stuff I can find have broken windows 09-Jan-20 11:44 AM Perhaps I can cannabalize one off a proportional counter? 09-Jan-20 11:46 AM I've always wondered how Alpha foil compares to Be Windows 09-Jan-20 11:46 AM but man, the sillys and sooo many neutron detectors 09-Jan-20 11:46 AM not very sensitive, but enough of them to build a big one 09-Jan-20 11:47 AM ohyeah those too :D 09-Jan-20 11:47 AM Surely you can't use 12 CHM-9 on your own? 09-Jan-20 11:47 AM i have some Ideas involving most of them 09-Jan-20 11:47 AM Ah I see 09-Jan-20 11:47 AM oh sure, angular detectors need lots 09-Jan-20 11:48 AM angular neutron distribution measurement, graded bonner sphere neutron spectrometer 09-Jan-20 11:48 AM yeh that 09-Jan-20 11:48 AM vaguely curious about attempting 1D imaging 09-Jan-20 11:48 AM the local reactor has an array of 1k He3 tubes over 60° iirc 09-Jan-20 11:48 AM there may be a sparse signals detection & reconstruction problem in here 09-Jan-20 11:50 AM time to spin some preamp boards and one fpga Mainboard 09-Jan-20 11:50 AM :D 09-Jan-20 11:50 AM gonna have to learn how to FPGA someday.. might as well be on a project orders of magnitude over my head 09-Jan-20 11:51 AM don't be afraid of the Hardware, be afraid of the maths you'll need to interpret your angular distribution 09-Jan-20 11:51 AM yeah that :D 09-Jan-20 01:34 PM same for any kind of bonner spectrometer unfolding.. all the codes used to do that are (perhaps predictably) trapped behind RSICC (at least in the 'states) and are based tremendously off of fitting against decades of experimental data 09-Jan-20 01:34 PM the amount of stuff that gets slurped under RSICC's purview and becomes otherwise wholly inaccessible to anyone not in the industry/academia is.. disappointing 09-Jan-20 06:49 PM congrats on the EDSs @qualia :) 10-Jan-20 12:05 AM ohh, interesting! 10-Jan-20 12:05 AM I have some liquid scintillators here with no data on them, one has a sticker saying "BoTri in EtOH" 10-Jan-20 12:05 AM so I contacted scionix (manufacturer of the PMT assembly for those scintillators) and got this: Hi Lukas, > > Latest news i got… > > The BoTri is very likely the standard compound known as trimethylborate. It is a clear liquid, and the preparation of it almost always involves ethyl alcohol (EtOH). In this case, the person probably purchased an ethyl alcohol solution containing the trimethylborate. > He then blended it into the UltimaGold liquid scintillator from Perkin Elmer. > > This is not a surprising idea. In fact if the researcher wasn't a chemist with some experience with scintillation liquids, he very well could have used this approach to make a boron loaded liquid scintillator. > > The cell described as 51A51 is likely an aluminum cell with a glass window cemented into it. The cavity likely is 51mm dia x 51mm long. > Sound like it all sort-of home made. > > Our liquid scintillators, EJ-339 and EJ-339A consist of an EJ-309 type scintillator in which we have blended trimethylborate in the pure state (no ethylalcohol). We can purchase the trimethylborate lliquid and simply clean it up and put it into EJ-339. For EJ-339A, we have to make the trimethylborate here using B10 enriched boron. > > I guess this does not really helps… > > Kind regards, 10-Jan-20 12:05 AM looks like someone actually made their own neutron sensitive liquid scintillator 10-Jan-20 12:17 AM very interesting...i wonder why? 10-Jan-20 12:20 AM I have no idea 10-Jan-20 12:20 AM also bad lab practice for not documenting that! 10-Jan-20 12:23 AM have a photo of it just for curiosity's sake? heh 10-Jan-20 12:32 AM sure do! 10-Jan-20 12:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/0-BD06F.png 10-Jan-20 12:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/0-0EFAF.png 10-Jan-20 12:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/0-05218.png 10-Jan-20 12:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/0-98982.png 10-Jan-20 12:34 AM oh that is a neat setup with the interchangeable liquid carriers 10-Jan-20 12:34 AM not sure i have seen that before 10-Jan-20 12:35 AM I haven't, for sure 10-Jan-20 12:38 AM i wonder if it is possible to find a paper about your set of liquid scintillators once you figure out what the others are (if you have not already) 10-Jan-20 12:38 AM https://www.perkinelmer.com/lab-solutions/resources/docs/APP_Cocktails-for-Liquid-Scintillation-Counting-011940_01.pdf There's this 10-Jan-20 01:51 AM oooh 10-Jan-20 01:51 AM interesting find 10-Jan-20 04:09 AM oh man 10-Jan-20 04:09 AM I just tested my HPGe adapter 10-Jan-20 04:10 AM oh? 10-Jan-20 04:10 AM pumped down, removed the plug, pumped down, refilled with argon, put the plug back in 10-Jan-20 04:10 AM everything went fine and as expected 10-Jan-20 04:10 AM but wow, that were some scary 10 minutes 10-Jan-20 04:11 AM hehehe 10-Jan-20 04:11 AM the detector had some air in it, and it's got a leak, that also fits in my diagnosis 10-Jan-20 04:11 AM so now I've got to turn on the leak tester, pump it down again, leak test 10-Jan-20 04:12 AM hehe fun 10-Jan-20 04:14 AM I both want to and don't want to pop the hood 10-Jan-20 04:14 AM but I'll have to, eventually 10-Jan-20 04:23 AM at first I'll do some writing for my website 10-Jan-20 05:25 AM https://gigabecquerel.wordpress.com/2020/01/10/canberra-hpge-repair-part-1-n/ 10-Jan-20 06:31 AM Damn my feed goes slow 10-Jan-20 06:33 AM what do you mean? 10-Jan-20 06:33 AM oh and also more detector repairs! 10-Jan-20 06:33 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200109_230028-3E14A.jpg 10-Jan-20 06:33 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200109_235740-D6C04.jpg 10-Jan-20 06:33 AM new foil for a new alpha / beta proportional detector 10-Jan-20 06:37 AM woot 10-Jan-20 06:39 AM so much productivity in one day 10-Jan-20 06:40 AM seriously, making me feel like your getting more done today than I got done all last year 10-Jan-20 06:41 AM yeah for some reason my productivity is way up recently 10-Jan-20 06:41 AM it's almost scary 10-Jan-20 06:41 AM the He tester, learning to code, the hpge, that prop thingy, many many things inbetween 10-Jan-20 06:42 AM well just don't burn out like I do... 10-Jan-20 06:42 AM I feel like I get going like that then I don't do anything for a month... or two... ugh 10-Jan-20 06:42 AM but man some of you guys are just super powered 10-Jan-20 06:42 AM maybe some of that radiation from work is helping :P 10-Jan-20 06:44 AM XD 10-Jan-20 06:44 AM must be a delayed reaction, atm I'm working in a coal Power plant :P 10-Jan-20 06:46 AM ah I thought you worked somewhere cleaning out radioactive stuff or something 10-Jan-20 06:48 AM I see phrases from people that wrote some time ago, then when I write, the feed actualizes, and I am answering to nobody. 10-Jan-20 06:48 AM did that 10-Jan-20 06:48 AM boss turned out to be a complete Maniac 10-Jan-20 06:49 AM ahhh 10-Jan-20 06:49 AM that sucks 10-Jan-20 06:57 AM I mean 10-Jan-20 06:57 AM I learned a lot and got lots of Equipment 10-Jan-20 06:57 AM so instead of suing him I'm just gonna keep that and forget about everything 10-Jan-20 06:57 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200110_160006-33B03.jpg 10-Jan-20 06:57 AM yay 10-Jan-20 06:57 AM now I can repair that prop detector 10-Jan-20 07:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200110_165034-B9EBE.jpg 10-Jan-20 08:05 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200110_165241-E751E.jpg 10-Jan-20 08:30 AM those liquid gas counters still weird me out a bit 10-Jan-20 08:30 AM but it works! 10-Jan-20 08:30 AM yay 10-Jan-20 12:15 PM OH THAT'S WHAT IT IS 10-Jan-20 12:18 PM I assume you're talking about my guessing game? 10-Jan-20 12:20 PM Wait, liquid gas? @GigaSquirrel 10-Jan-20 12:20 PM How does that work? 10-Jan-20 12:20 PM I'm not sure that's the correct term 10-Jan-20 12:20 PM the gas in lighters, not lighter fluid 10-Jan-20 12:20 PM those propane / butane mix thingies 10-Jan-20 12:21 PM is it actually liquid and under pressure? 10-Jan-20 12:21 PM aye 10-Jan-20 12:21 PM that'd suck to set down on a tack or staple by accident 10-Jan-20 12:22 PM the prop chamber has a small reservoir for the liqud and some clever pressure regulation, the actual detection area has like 500 mbar above atmosphere 10-Jan-20 12:22 PM but yeah 10-Jan-20 12:22 PM huh 10-Jan-20 12:22 PM why does it make the whooshy sound then? 10-Jan-20 12:23 PM poke it and you'll have a constant supply of flammable gas 10-Jan-20 12:23 PM that's the reservoir and pressure regulation 10-Jan-20 12:23 PM that was the first fill 10-Jan-20 12:23 PM I wonder how it makes a differential pressure in a closed system 10-Jan-20 12:24 PM it's got a capillary from the liquid to the chamber and an over pressure valve from the chamber to atmosphere 10-Jan-20 12:24 PM so it's just constantly dumping gas, slowly? 10-Jan-20 12:25 PM that's the whole point 10-Jan-20 12:25 PM I don't know their english name, in german it's Durchflusszählrohr, flow through counting tube 10-Jan-20 12:26 PM proportional flow counter 10-Jan-20 12:26 PM I always thought they were a self-contained system 10-Jan-20 12:26 PM gas maker/capturer dingus and hoses 10-Jan-20 12:26 PM nah 10-Jan-20 12:26 PM not just a tank you fill and let evaporate slowly 10-Jan-20 12:26 PM how long does it last? 10-Jan-20 12:26 PM couple of hours per fill 10-Jan-20 12:27 PM ouch 10-Jan-20 12:27 PM the flow is minute, not even enough to sustain a flame 10-Jan-20 12:27 PM "give me a minute to refill my detector" 10-Jan-20 12:27 PM pulls out lighter gas tank 10-Jan-20 12:27 PM well 10-Jan-20 12:27 PM that's spot on 10-Jan-20 12:28 PM But it's sensitive and very large area 10-Jan-20 12:28 PM So I guess a dollar per hour operating price isn't too bad 10-Jan-20 12:28 PM Not to mention discrimination 10-Jan-20 12:28 PM the gas is basically free 10-Jan-20 12:28 PM a buck or less for a bottle that will last you manymany fills 10-Jan-20 12:29 PM tens or hundreds? 10-Jan-20 12:29 PM tens 10-Jan-20 12:30 PM probably need a filter inline with the charging port to catch all the nasty odorant 10-Jan-20 12:30 PM my mapp gas tank has low quality, condensing odorant 10-Jan-20 12:30 PM drips straight out of the reducer 10-Jan-20 12:31 PM if you wanna go extreme, I once owned this tritium detector 10-Jan-20 12:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20180927_121446-12645.jpg 10-Jan-20 12:31 PM ah. 10-Jan-20 12:31 PM yes. 10-Jan-20 12:31 PM big bottle of P10 gas, windowless detector 10-Jan-20 12:31 PM oh okay, not that way 10-Jan-20 12:31 PM I thought the detector was filled with kilocuries of tritium :P 10-Jan-20 12:32 PM no need to filter out the odorant, you can build a proportional detector with literally anything# 10-Jan-20 12:32 PM it's just going to get nasty 10-Jan-20 12:33 PM prop counter doesn't care 10-Jan-20 12:33 PM if it gets too bad just flush it out with IPA 10-Jan-20 12:35 PM What do you use for the foils? 10-Jan-20 12:36 PM alpha foil 10-Jan-20 12:36 PM aluminized mylar 10-Jan-20 12:36 PM suppliers suppliers suppliers 10-Jan-20 12:36 PM gotta know where to get it cheap 10-Jan-20 12:37 PM one of my twitter followers works in a lab 10-Jan-20 12:37 PM maybe I should become popular on twitter 10-Jan-20 12:37 PM ¯\_(ツ)_/¯ 10-Jan-20 01:53 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200110_224242-65628.jpg 10-Jan-20 01:53 PM ohhh boi 11-Jan-20 02:55 AM No leaks found! 11-Jan-20 02:55 AM woot! I saw :) 11-Jan-20 02:55 AM just needs a good baking huh? 11-Jan-20 02:55 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200111_105401-19AAF.jpg 11-Jan-20 02:55 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200111_115420-DFAE7.jpg 11-Jan-20 02:55 AM it's never real science without copious amounts of Al foil 11-Jan-20 02:56 AM :P 12-Jan-20 08:18 AM https://www.youtube.com/watch?v=ACWuG8Mea-M Ayyy I did not break it any further! 12-Jan-20 08:18 AM for actual testing I need LN2 :< 12-Jan-20 01:00 PM https://gigabecquerel.wordpress.com/2020/01/12/fag-fht-111-contamat-repair/ 12-Jan-20 03:40 PM anyone know of a decent, small, open source geiger counter? pretty basic stuff so it would be nice to just be able to copy an existing design to throw together a pocket size geiger counter using this LND712 tube i have 12-Jan-20 04:01 PM @LRM can you build the power supply? 12-Jan-20 04:01 PM that's the hardest part 12-Jan-20 04:24 PM probably, with some effort. i get by at electronics stuff but am nowhere near where many of you are at 12-Jan-20 04:24 PM the LND712 needs around 500V afaik 12-Jan-20 04:24 PM most of the circuits already out there can definitely supply that but i would love to not have to go through the effort of whipping up my own boards and everything 12-Jan-20 04:31 PM 500V is not particularly easy to generate 12-Jan-20 04:31 PM https://www.ebay.com/itm/Geiger-Muller-tube-EVM-High-voltage-power-supply-Signal-processing/184050854181 12-Jan-20 04:31 PM grab something like this 12-Jan-20 04:31 PM tube goes on one end, microcontroller on the other, happiness results 12-Jan-20 04:36 PM is there a reason not to just use a setup like this uses? https://www.dropbox.com/s/ai8uu5s3so7y12r/GK-Plus%20v2_2%20Schematic%20%28conflicted%29.png?dl=raw 12-Jan-20 04:36 PM probably with slightly different component choices 12-Jan-20 04:36 PM unregulated output 12-Jan-20 04:40 PM i like that better than the $50 HV supply on ebay based on component costs heh 12-Jan-20 04:40 PM I linked a cheaper one 12-Jan-20 04:40 PM also @GigaSquirrel https://www.ebay.com/itm/NaI-Tl-150-100mm-Scintillation-gamma-detector-Resolution-12-Built-in-preamp/223616087601 12-Jan-20 04:40 PM @LRM https://www.ebay.com/itm/Adjustable-HV-high-voltage-supply-module-for-geiger-tube-counter-and-dosimeter/163698628750 12-Jan-20 04:40 PM here's an even cheaper supply 12-Jan-20 04:40 PM but you'll need a bit of pulse detection circuitry 13-Jan-20 08:16 AM @GigaSquirrel Probably I missed it, but can you tell me how much you paid for HPGe? I kinda played enough with NaI at 7%... 13-Jan-20 08:17 AM Swapped it for a tritium contamination monitor that I once paid like 20 bucks for 13-Jan-20 08:18 AM I doubt I will ever get that lucky ) Would you say 500-1000$ is too much at ebay for not knowing working or not? 13-Jan-20 08:19 AM It totally depends on your financial Situation, how good you are at repairing stuff and how much it is worth to you 13-Jan-20 08:19 AM I am personally slowly moving from buy cheap spend time fixing to buy expensive and use myself... 13-Jan-20 08:19 AM The thing is, many of them go for quite cheap or even free right from the labs 13-Jan-20 08:20 AM buying projects that are pieces to other projects is a doubling equation gone wrong 13-Jan-20 08:20 AM oh I am totally for waiting for a working thing for the right price 13-Jan-20 08:20 AM that is cool 13-Jan-20 08:20 AM but I am being way more careful with buying used 13-Jan-20 08:20 AM I almost got a 40% ortec one for free, some other complication hindered that 13-Jan-20 08:21 AM also I hate roughing pumps, not relevant for this convo but I hate them 13-Jan-20 08:21 AM yea sometimes deals fall through 13-Jan-20 08:21 AM XD 13-Jan-20 08:21 AM But seriously, I see everyone else get their little used roughing pump and it runs for years 13-Jan-20 08:21 AM mine seem great or even rebuilt a few years ago then sat on a shelf 13-Jan-20 08:21 AM then they proceed to puke oil all over my floor 13-Jan-20 08:21 AM out of every which different seal 13-Jan-20 08:21 AM 3 pumps in a row this has happened to me 13-Jan-20 08:21 AM the two before that tested very bad and in much need of rebuild 13-Jan-20 08:22 AM hehe, whoops 13-Jan-20 08:22 AM but yea... I have like... uhm 13-Jan-20 08:22 AM 11? maybe 12? roughing pumps at this point laying about the basement 13-Jan-20 08:22 AM only the one on my SEM that I did a partial rebuild on replacing some seals and orings runs nice and doesn't puke oil 13-Jan-20 08:24 AM I totally get your opinion in price vs repair time, but on the other hand, if the hpge repair worked I will definitely put that on my resume 13-Jan-20 08:24 AM I got my first official minor rebuild kit for one of mine on the way from duniway, I am concerned about how much is included in that kit... but we will see 13-Jan-20 08:24 AM hehe absolutely! 13-Jan-20 08:24 AM honestly some things are still worth getting broken just due to rarity, price, or well not being a part of an end goal but just a curiosity 13-Jan-20 08:27 AM Yeah definitely 13-Jan-20 09:39 AM what sort of oil are you using and is there any chance there is some contamination that is destroying the seals? 13-Jan-20 09:39 AM 3 pumps in a row is pretty terrible luck 13-Jan-20 11:33 PM @Conmega wow that's a crazy number of pumps... Maybe you just are too quick with your eBay trigger finger? 14-Jan-20 02:37 AM @nmz787 all but 3 of them I got for pennies on the dollar from an auction in NJ, IE like 50 bucks for a lot of 5 pumps... 14-Jan-20 02:39 AM Well, hard to complain then 14-Jan-20 02:41 AM Yea, but still if a full rebuild of a pump costs like 300 bucks you end up paying 300 per pump in the end which while still cheap isn't just like a 100 dollar pump score lol 14-Jan-20 02:41 AM Not to mention rebuilding a pump is a pain especially if you don't have a big enough ultrasonic to really clean the parts nicely. 14-Jan-20 05:43 PM That’s why I like Welch 1402’s they are pretty bullet proof and can be rebuilt in an afternoon. The low RPM is key to their long lives. 14-Jan-20 11:14 PM Ok this feels very weird to say on on this server, but all the pump talk is a bit off topic here... 14-Jan-20 11:14 PM let's move this to #general or #off-topic-thats-sometimes-on-topic before we contaminate any innocent pumps 15-Jan-20 10:05 AM https://gigabecquerel.wordpress.com/2020/01/15/canberra-hpge-repair-part-2-n/ 15-Jan-20 10:46 AM \o/ 15-Jan-20 05:21 PM I just saw an awesome meter 15-Jan-20 05:21 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/s-l1600-40978.png 15-Jan-20 05:21 PM I really like how the display is made! 15-Jan-20 05:21 PM LCD scale(that I assume adapts), with a digital readout, but also a needle 15-Jan-20 05:21 PM this would be perfect for a radiation ratemeter 15-Jan-20 05:21 PM I'm actually really tempted to make that myself 16-Jan-20 12:55 AM Well you COULD order a batch of custom LCD's from china 16-Jan-20 12:55 AM eevblog Dave did that and that dude who made a batch of TRS-80 displays also did so. 16-Jan-20 03:29 AM http://canberra-industries-50years.com/ Pretty interesting and some very nice pictures 16-Jan-20 03:50 AM Well at least they're honest XD 16-Jan-20 03:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1A3DF.png 16-Jan-20 04:02 AM For about a week we called this detector the Wide-Energy Ge (WEGe) Detector. Orren introduced this product at a Canberra User’s Group Meeting and suddenly realized that no one who had ever been a schoolboy in the US would pay money for a WEGE, so we promptly change the name. 16-Jan-20 06:41 PM <__ice9#6039> I have apparently successfully sintered thorium dioxide by flash sintering at ~400W excess power dissipation using ~2300V AC across a green form ~35mm long at 900C preheat with galinstan end-contacts. 16-Jan-20 06:41 PM <__ice9#6039> Unfortunately the green form was of insufficient density and using a silica tube to contain it caused a star crack gap down the center 16-Jan-20 06:41 PM <__ice9#6039> Future attempts will need a proper press to make a freestanding green form resting on a layer of thoria powder. 16-Jan-20 06:41 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200115_220618-58F08.jpg 16-Jan-20 06:41 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200115_220640-A2714.jpg 16-Jan-20 06:41 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200115_210620-25724.jpg 16-Jan-20 06:41 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200116_051714-2EE21.jpg 16-Jan-20 06:46 PM Oh dear, which bit is the ThO2? 16-Jan-20 06:46 PM The white powder inside the glass? 16-Jan-20 06:46 PM <__ice9#6039> Later attempts will hopefully avoid the central splitting. I may use graphite or zirconia to convey the current to the form as well, preventing that reddish contamination from the stainless steel bolts behind the galinstan 16-Jan-20 06:46 PM <__ice9#6039> The stuff in the center, inside the glass tube that split open 16-Jan-20 06:48 PM What's the goal of sintering here? 16-Jan-20 06:48 PM <__ice9#6039> The piece that fell off shown in the center there is sintered thoria. It's quite hard and not frangible anymore, except at the reddish discolored margin 16-Jan-20 06:48 PM <__ice9#6039> Making sintered thoria rods to use for very high temperature furnace applications 16-Jan-20 06:48 PM <__ice9#6039> Initially: to see if I could actually pull it off 16-Jan-20 06:48 PM <__ice9#6039> Ultimately: to make rods/tubes/crucibles 16-Jan-20 06:48 PM <__ice9#6039> I am intrigued by the idea of using stabilized zirconia to make air-stable pure ceramic heating elements usable to ~2200-2400C. Those in turn require an insulator however. Graphite rods should be ok for conveying the operating current to the elements. But the element mounts need to insulate the elements from the surrounding furnace walls, which at nearly the same temperature will conduct nearly as well as the elements themselves. Other applications exist as well, granted. 16-Jan-20 06:48 PM <__ice9#6039> Thorium dioxide when sufficiently preheated also becomes a microwave susceptor, potentially of interest in a microwave furnace 16-Jan-20 06:58 PM radioactive crucibles that shed dust 16-Jan-20 06:58 PM yum 16-Jan-20 06:59 PM <__ice9#6039> I'm thinking about trying to outright fuse it using a skull crucible method. This requires a bit of metallic thorium to initiate the reaction, though. I am currently attempting to fluoridate some ThO2 via ammonium bifluoride to calcine the resulting complex fluoride into ThF4 which can be reduced to Th metal in a process using calcium and zinc. 16-Jan-20 06:59 PM <__ice9#6039> All ceramics shed dust and it would be unwise to work with them without respiratory protection 16-Jan-20 06:59 PM <__ice9#6039> Many are also rather strong skin irritants, so it's common to go through large numbers of gloves while casting them 16-Jan-20 07:00 PM The issue is that thorium is an alpha emitter 16-Jan-20 07:00 PM It's alriiiightish outside your body, but a catastrophe when it's inside 16-Jan-20 07:00 PM As for ThO2 reduction - can't you just do a direct reduction in extreme heat? 16-Jan-20 07:01 PM <__ice9#6039> Wow I had no idea 16-Jan-20 07:02 PM Find something that will steal the oxygen 16-Jan-20 07:02 PM Seems like, with a furnace, it's a bit easier pratically 16-Jan-20 07:02 PM (and safer) 16-Jan-20 07:02 PM (disclaimer: chemistry and me are not friends) 16-Jan-20 07:03 PM <__ice9#6039> I have read of another process for direct reduction of ThO2, true. The most common method is via the tetrafluoride 16-Jan-20 07:03 PM <__ice9#6039> But that might be simpler in practice, idk -- will poke around a bit more 16-Jan-20 07:03 PM "The most common" probably means "in high end labs" because you don't often do Th chemistry 16-Jan-20 07:04 PM <__ice9#6039> Oh I see-- that's right. Yes it needed an argon furnace. 16-Jan-20 07:04 PM That's relatively simple 16-Jan-20 07:04 PM But what do you react it with? 16-Jan-20 07:05 PM <__ice9#6039> I hadn't examined that approach much further because I didn't have an argon furnace. That will change relatively soon, though. 16-Jan-20 07:05 PM It's neat that someone in this community is finally doing thorium chemistry 16-Jan-20 07:05 PM I have a bit(in metal sintered form) but haven't had a use for it yet 16-Jan-20 07:06 PM <__ice9#6039> Usually still just calcium metal, but that method allows skipping the fluoride which will save a lot of time 16-Jan-20 07:06 PM <__ice9#6039> Making the fluoride takes several days plus additional processing steps 16-Jan-20 07:06 PM <__ice9#6039> Hmm well, you could use small pieces of it to initiate thoria skull crucibles ^^ 16-Jan-20 07:06 PM <__ice9#6039> I will say that direct dissolution of ThO2 in HNO3 and HF does not work very well, huge quantities of HNO3 are needed 16-Jan-20 07:09 PM Do you want to build ThO2 or Th crucibles? 16-Jan-20 07:10 PM <__ice9#6039> Yes among other things, but I am also interested in trying to fuse it into monocrystalline forms if possible 16-Jan-20 07:10 PM I'm guessing "yes" means both 16-Jan-20 07:10 PM <__ice9#6039> I have seen at least some research suggesting that this is possible but am unsure whether I can hit sufficient temperatures with a 3kW magnetron 16-Jan-20 07:10 PM <__ice9#6039> Oh, ThO2 lol 16-Jan-20 07:10 PM <__ice9#6039> Metallic Th would be a silly thing to use for a crucible 16-Jan-20 07:11 PM What about platinum or iridium? 16-Jan-20 07:11 PM Those fancy externally supported, foil-thin crucibles 16-Jan-20 07:11 PM The ones that don't cost $25k each 16-Jan-20 07:12 PM <__ice9#6039> I already have stainless, nickel, and zirconium crucibles. I don't want to pay up for a platinum one. I own about 50g of an iridium-ruthenium alloy and am working on a 15kW induction furnace, so it might be possible to cast from that someday 16-Jan-20 07:13 PM 50g is a lot if it favors iridum :P 16-Jan-20 07:13 PM <__ice9#6039> Into magnesia 16-Jan-20 07:13 PM <__ice9#6039> About 70% Ir yep 16-Jan-20 07:13 PM <__ice9#6039> There's a story behind that but it's lengthy 16-Jan-20 07:13 PM I don't think they're cast, I think they're drawn out of foil 16-Jan-20 07:13 PM <__ice9#6039> They're usually formed by molten cyanide electroforming actually. 16-Jan-20 07:13 PM <__ice9#6039> The material is too brittle to stamp 16-Jan-20 07:14 PM oh iridium isn't that expensive 16-Jan-20 07:14 PM just around $1/g 16-Jan-20 07:14 PM <__ice9#6039> I don't like cyanides enough to do it that way though 16-Jan-20 07:14 PM <__ice9#6039> Um no lolol 16-Jan-20 07:14 PM <__ice9#6039> If that were true I would own a lot more of it 16-Jan-20 07:14 PM ah, no, that's $1k per troy ounce 16-Jan-20 07:14 PM okay :P 16-Jan-20 07:15 PM <__ice9#6039> Anyway if this induction furnace can manage the temps then it would be best to cast it into magnesia 16-Jan-20 07:15 PM that's still not unreasonable 16-Jan-20 07:15 PM <__ice9#6039> And then acid etch the magnesia back off 16-Jan-20 07:15 PM if the induction furnace is direct heating then it will easily keep up those temps 16-Jan-20 07:15 PM just have to insulate well 16-Jan-20 07:15 PM <__ice9#6039> I'm hoping to use a magnesia mold and directly melt the powder in the mold and sprues yeah 16-Jan-20 07:15 PM <__ice9#6039> Insulation should be ok 16-Jan-20 07:16 PM it should only weigh a few grams if you make the crucible really thin 16-Jan-20 07:16 PM maybe 100um or something 16-Jan-20 07:16 PM <__ice9#6039> Setter plate is stabilized reticulated zirconia so thermal conduction losses should be very low 16-Jan-20 07:16 PM <__ice9#6039> That's hard to do by casting.... 16-Jan-20 07:16 PM make a two part mold that you fill with powder? 16-Jan-20 07:16 PM or grow the iridium on something, as you said 16-Jan-20 07:17 PM <__ice9#6039> That's why they usually use molten cyanide, but I'm not inclined to dabble in that particular dark art. Making any decent amount of cyanide was hard enough, that would need huge amounts of it, and the process is too dangerous. 16-Jan-20 07:17 PM make a thick crucible form, grow it on the form, selectively dissolve the form 16-Jan-20 07:17 PM I was thinking something closer to electroplating 16-Jan-20 07:18 PM <__ice9#6039> Yes 2-part was the idea 16-Jan-20 07:18 PM <__ice9#6039> Yes that's electroforming 16-Jan-20 07:18 PM still sort of needs cyanide but in solution 16-Jan-20 07:18 PM not molten 16-Jan-20 07:18 PM <__ice9#6039> Iridium electroplating is much harder than silver 16-Jan-20 07:18 PM what dissolves iridium? 16-Jan-20 07:18 PM <__ice9#6039> Very little. 16-Jan-20 07:18 PM aqua regia? 16-Jan-20 07:18 PM <__ice9#6039> Nope 16-Jan-20 07:18 PM HF? 16-Jan-20 07:19 PM <__ice9#6039> Nope 16-Jan-20 07:19 PM ... hot HF? 16-Jan-20 07:19 PM <__ice9#6039> I did dissolve some in fluoridated aqua regia once 16-Jan-20 07:19 PM <__ice9#6039> And got IrF6 16-Jan-20 07:19 PM Hell, 10g Fluorinated hell, 10g 16-Jan-20 07:19 PM <__ice9#6039> And some ruthenium fluorides 16-Jan-20 07:20 PM IrF6 is just a surprising compound to own 16-Jan-20 07:20 PM "you have what?" 16-Jan-20 07:20 PM <__ice9#6039> Lolol 16-Jan-20 07:20 PM <__ice9#6039> Like 200mg of it 16-Jan-20 07:20 PM <__ice9#6039> Those were very small studies given material cost 16-Jan-20 07:20 PM 200mg is enough to fill a small ampoule 16-Jan-20 07:20 PM very visible 16-Jan-20 07:21 PM <__ice9#6039> Oh it was visible yes 16-Jan-20 07:21 PM <__ice9#6039> Yellow crystals, slightly greenish 16-Jan-20 07:21 PM fluorine tends to make stuff green 16-Jan-20 07:23 PM <__ice9#6039> That was also one of the few things that I was able to use to dissolve tantalum 16-Jan-20 07:23 PM <__ice9#6039> The result was more white there 16-Jan-20 07:23 PM what was the goal? 16-Jan-20 07:34 PM <__ice9#6039> Proving that a different iridium seller was trying to defraud me by sending tantalum instead lol 16-Jan-20 07:34 PM <__ice9#6039> Got that one refunded. 16-Jan-20 07:34 PM <__ice9#6039> Also had XRF results 16-Jan-20 07:39 PM lol 16-Jan-20 07:39 PM ultimate pettiness 16-Jan-20 08:07 PM <__ice9#6039> Usual Chinese scam: send a good batch first, then try to screw the customer on reorder 16-Jan-20 08:22 PM <__ice9#6039> Quick literature survey does not turn up any aqueous method for iridium electroforming-- only plating to a maximum depth of a few microns, PVD, or fused salt electrodeposition. To the best of my knowledge, those crucibles are still being made by molten cyanide electroforming. 16-Jan-20 08:22 PM <__ice9#6039> Anyway this is all off topic at this point >____> 17-Jan-20 12:07 PM https://www.nde-ed.org/EducationResources/CommunityCollege/Radiography/Physics/HalfValueLayer.htm 17-Jan-20 12:07 PM Good thing to pin 17-Jan-20 03:49 PM https://www.youtube.com/watch?v=9Ry4QBQejFU 17-Jan-20 03:49 PM so...what do you do with the heater after you eat your ration? 17-Jan-20 04:12 PM Also possibly slightly off topic but somewhat related. Does anyone know where the steam turbines go to get reworked when they are taken out of service from nuclear power plants? Was driving home from Arizona today and think I saw some of the stators from Palo Verde Generating Station on a truck. Each one was nearly as big as my car! 17-Jan-20 04:26 PM Where can I get one of those hearers... 17-Jan-20 04:31 PM presumably in a Scottish army ration? 17-Jan-20 04:31 PM also i think that might be something you need a license for in the USA 17-Jan-20 05:27 PM Shhhhhhhh 18-Jan-20 10:22 AM anyone have a good reference on PMT interfacing? i'm trying to improve my scintillation detector linearity and am not sure about using a opamp current to voltage converter or a load resistor. another thing i've been wondering about is using a single cable (bias on signal wire) versus a power + signal cable 18-Jan-20 10:22 AM with the bias on signal setup the output signal is the current over all dynodes + the anode whereas for the separate cables it is only anode current. 18-Jan-20 10:44 AM also, at the moment i have a PSU with a annoyingly large output ripple, which i am countering by subtracting the ripple from the output 18-Jan-20 11:14 AM you need to decouple the signal through a capacitor, after that you should just get a negative going signal that you can invert with an opamp 18-Jan-20 11:14 AM scintillation detectors are never quite linear 18-Jan-20 11:14 AM you'll need to calibrate it out using known sources 18-Jan-20 11:14 AM what you're looking for is not linearity, but signal shape - FWHM resolution of your peaks 18-Jan-20 11:14 AM the lower it is, the better 18-Jan-20 11:14 AM but that also depends on your scintillator crystal's shape/size and the way it's attached 18-Jan-20 11:20 AM is there any easy way to diagnose a problem with either the PMT or voltage divider on a scintillator? i was given a gamma spectacular thing a few years ago by someone who also was given it by someone else, got a few decent counts out of it that made sense for what i was measuring and then suddenly nothing. 18-Jan-20 11:20 AM stuck it in a box to figure out whats wrong down the road because i had other stuff going on at the time but just saw the box earlier and then people were talking about them, how convenient 18-Jan-20 11:24 AM disconnect the box, measure the bias voltage 18-Jan-20 11:24 AM then measure the current going from bias to the pmt 18-Jan-20 11:24 AM if it's too high(many mA), you're got a light leak or a shot PMT 18-Jan-20 11:24 AM if it's not, your box is likely dead 18-Jan-20 11:27 AM the gamma spectacular thing puts out the correct voltages but i have not checked the current through the PMT 18-Jan-20 11:27 AM hopefully the PMT is not dead and it is just a resistor or something in the voltage divider being the problem 18-Jan-20 11:28 AM that was the case for my alpha spectra probes 18-Jan-20 11:28 AM (after my mods, years ago) 18-Jan-20 11:35 AM spirit: i only have a negative supply, so anode is at ground potentia;l 18-Jan-20 11:36 AM that doesn't really matter 18-Jan-20 11:36 AM as long as it's connected the right way 18-Jan-20 11:36 AM i'm just wondering what resistance value i should have at the pmt anode 18-Jan-20 11:36 AM which pmt do you have? 18-Jan-20 11:37 AM xp2202 18-Jan-20 11:37 AM there is generally no resistor at the anode 18-Jan-20 11:37 AM only on the dynodes 18-Jan-20 11:37 AM thus creating a voltage gradient 18-Jan-20 11:39 AM isn't there a resistor on the anode to convert signal current to voltage? 18-Jan-20 11:40 AM that's one way, but using a capacitor is another 18-Jan-20 11:40 AM probably better in your case 18-Jan-20 11:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3E467.png 18-Jan-20 11:40 AM this is what i'm working off 18-Jan-20 11:42 AM place a capacitor at "SIGNAL OUTPUT" 18-Jan-20 11:42 AM a small, high voltage rated cap 18-Jan-20 11:42 AM http://physicsopenlab.org/2016/04/21/pmt-pulse-processing/ 18-Jan-20 11:42 AM there needs to be a dc path from anode to the power supply, righT? 18-Jan-20 11:43 AM yes, you also need a resistor from the anode 18-Jan-20 11:43 AM but the signal is usually decoupled with a capacitor 18-Jan-20 11:44 AM right. so, what would that resistor have to be? 18-Jan-20 11:45 AM usually the same as your dynodes, or around 1M 18-Jan-20 11:45 AM the output cap should be around 100nF 18-Jan-20 11:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/PMT_Voltage_Divider-5272D.png 18-Jan-20 11:45 AM this is a simpler looking schematic 18-Jan-20 11:45 AM the output arrow goes to an AC coupling cap, then to an amplifier 18-Jan-20 11:45 AM I'd start with a 1M load resistor, keep your dynodes untouched 18-Jan-20 11:45 AM that will lower your resolution a little because the pulse will be a bit longer 18-Jan-20 05:22 PM preamp seems to work, but clips easily at the moment. might need to make the Cf larger (its 6.8pF atm) 18-Jan-20 06:02 PM or a higher load resistor 18-Jan-20 06:02 PM higher load = shorter pulses but also weaker 18-Jan-20 06:02 PM (former is good, latter not so much) 18-Jan-20 07:56 PM this is the spectrum measured for some vacuum tube marked as radioactive: 18-Jan-20 07:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1CDF4.png 18-Jan-20 07:59 PM is it actually radioactive? 18-Jan-20 08:00 PM tubes that are "radioactive" just mean thoriated tungsten filaments generally I thought 18-Jan-20 08:00 PM Not always, @Conmega 18-Jan-20 08:00 PM Those are one kind 18-Jan-20 08:01 PM yep. count goes up a lot when i put it into the scintillator well 18-Jan-20 08:01 PM How far away? And what's the count rate difference? 18-Jan-20 08:01 PM its not a beam triode/ hv diode / other x ray source 18-Jan-20 08:01 PM Rectifier? 18-Jan-20 08:01 PM Or spark gap? 18-Jan-20 08:01 PM 10s per second to several 100s per second (scope trig maxed out ) 18-Jan-20 08:01 PM seems to be a thyratron 18-Jan-20 08:02 PM Using a scope is a bit inadequate 18-Jan-20 08:02 PM Because it's a rather low resolution 18-Jan-20 08:02 PM You're also getting a really weird spectrum 18-Jan-20 08:02 PM That spike on the right can't exist 18-Jan-20 08:02 PM thats clipping 18-Jan-20 08:03 PM It's likely a Cs-137 tube 18-Jan-20 08:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/nFEd4-1C845.png 18-Jan-20 08:03 PM this is what you're supposed to be seeing 18-Jan-20 08:03 PM This is closer to what you're seeing 18-Jan-20 08:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Caesium-137_gamma_ray_NaI_scintillator_spe-2E7E1.png 18-Jan-20 08:03 PM But, two issues: Nonlinearity and pulse shaping 18-Jan-20 08:03 PM Your pulses are "smearing" the spectrum 18-Jan-20 08:03 PM You want to see a nice, sharp, short pulse 18-Jan-20 08:03 PM It's definitely a Cs-137 tube though 18-Jan-20 08:05 PM i'm ignoring weak pulses, theres just too many of them 18-Jan-20 08:06 PM Do not ignore them! 18-Jan-20 08:06 PM That's the x-rays. 18-Jan-20 08:06 PM It seems like you're slashing off the first 100keV of spectrum or thereabouts 18-Jan-20 08:06 PM If you're seeing a distinct pulse, it's valid. 18-Jan-20 08:08 PM so, what would make a good mca? i have some 12bit 52MSPS adcs lying around, could hook one of those up to a fpga 18-Jan-20 08:08 PM That'd be overkill but you could use that to do peak detection in the fpga and skip a bunch of analog logic 18-Jan-20 08:08 PM 12b is good, 16 is better 18-Jan-20 08:08 PM Bit depth directly defines your energy bin resolution, the amplifier chain should be adjusted to stuff high energy cosmic rays close to the limit while retaining range 18-Jan-20 08:08 PM a lot of the MCAs are just sound card based, either in-computer or discrete chip, so 14, 16, or even 24 bit at 44-192ksps 18-Jan-20 08:13 PM then i'll need to do some heavy pulse shaping 18-Jan-20 08:13 PM pulse shaping is integral anyway, but I've had good success with just amplifying a PMT signal and stuffing it into a sound card 18-Jan-20 08:13 PM even made a video about a $2 DIY MCA 18-Jan-20 08:13 PM this is just directly looking at the charge sensitive amp output 18-Jan-20 08:13 PM (through a buffer stage) 18-Jan-20 08:13 PM atm my Cf = 13.6pF, R = 1M. but because of the clipping and lots of pulses riding on the tail of others i'm considering lowering the bleeder resistor value somewhat 18-Jan-20 08:16 PM change the load resistor to 100k 18-Jan-20 08:16 PM see what difference that makes 18-Jan-20 08:16 PM and don't cut the bottom off 18-Jan-20 08:16 PM you will also want to represent it as a logarithmic output, not linear 18-Jan-20 08:16 PM (the graph that is) 18-Jan-20 08:42 PM the graph was log 18-Jan-20 08:42 PM changed it, pulses are shorter, still a lot of clipping and reso does not seem significantly better 18-Jan-20 08:43 PM clipping is also bad 18-Jan-20 08:43 PM you shouldn't see any clipping at all 18-Jan-20 08:43 PM drop the first preamp stage's output 18-Jan-20 08:46 PM this is my schematic 18-Jan-20 08:46 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/P1010157-B83D0.png 18-Jan-20 08:46 PM show me the preamp input and preamp output 18-Jan-20 08:46 PM also, there should be a capacitor between the pmt output and the preamp input 18-Jan-20 08:46 PM I also don't see a load resistor from the PMT's output to ground 18-Jan-20 08:46 PM https://i.spirit.re/mnlbr.png 18-Jan-20 08:48 PM why would that be needed in this case, pmt output is at ground potential so the opamp provides the DC path 18-Jan-20 08:48 PM no decoupling cap needed in this case 18-Jan-20 08:49 PM except there's going to be a DC current at the output 18-Jan-20 08:49 PM a small one, but a current nonetheless 19-Jan-20 04:45 AM the tube pbx was measuring is an ob2 voltage regulator, and internet tells me it's supposed to have a thoriated tungsten filament. 19-Jan-20 04:48 AM huh? 19-Jan-20 04:48 AM a voltage regulator with a filament? 19-Jan-20 04:48 AM I only know of the glow discharge type 19-Jan-20 04:48 AM and I'm pretty sure the OB2 is glow discharge, with a big of Radium inside 19-Jan-20 07:06 AM hah, i think you 19-Jan-20 07:06 AM 're right, thats what late night googling gets you i suppose. it seems to be a cold cathode device 19-Jan-20 07:06 AM its a military version, with a nato stock number, but i am pretty sure its ab ob2 all the same. 19-Jan-20 07:18 PM does anyone prefer Bicron Surveyor M vs Ludlom counters? about to make a purchase on one, trying to differentiate them 19-Jan-20 07:18 PM looking at Ludlum 3 + 44-9 probe for $270, Ludlum 14C + 44-9 probe for $400, 44-9 probe by itself $225 + Bicron Surveyor M $75 19-Jan-20 07:18 PM i'd also like to detect x-rays, trying to see if that's just a different probe 19-Jan-20 08:27 PM That is just a different probe 19-Jan-20 08:27 PM you don't need to spend that much money on a 44-9 probe though 19-Jan-20 08:27 PM https://www.ebay.com/itm/Eberline-HP-260-GM-Pancake-Probe-Tested-Working-Radiation-Geiger-A-B-G/274099717427 19-Jan-20 08:27 PM this is essentially the same probe but under a different name 19-Jan-20 08:32 PM ahh 19-Jan-20 08:32 PM does ludlum 3 vs 12 vs 14 vs Bicron Surveyor M make much of a difference? 19-Jan-20 08:33 PM not really, no, they're pretty much the same thing 19-Jan-20 08:33 PM oh, here's a unit I linked earlier 19-Jan-20 08:33 PM https://www.ebay.com/itm/Dosimeter-Model-3100-Survey-Meter-with-Bicron-GI-LE-Probe/323743224389 19-Jan-20 08:33 PM the meter itself... I don't really know, but that probe is super rare and that is what you want for x-rays, low energy gamma, and alpha-ish measurements, worth the $130 alone 19-Jan-20 08:33 PM I can't find any info on that meter 19-Jan-20 08:33 PM but it looks like it's a working scaler, and maybe you can tweak the voltage 19-Jan-20 08:33 PM that should be good enough 19-Jan-20 08:33 PM you can see this probe screaming at alpha and low energy x-rays here: 19-Jan-20 08:33 PM https://www.youtube.com/watch?v=kGERXzl84sk& 19-Jan-20 09:26 PM ahh nice 19-Jan-20 09:26 PM is it easy to recalibrate these? 19-Jan-20 09:26 PM just ordered a Ludlum 3 (that "doesn't turn on") with 44-9 probe for $170...seemed i couldn't find the probe by itself cheaper than that, and hopefully should be easy to resolve the ludlum issue 19-Jan-20 09:38 PM No calibration needed, these devices are count rate meters 19-Jan-20 09:38 PM They won't tell you a dose rate unless you do serious math on it 20-Jan-20 09:24 AM I have a model 3 with a 44-9 that I use for alpha detection. Mostly I just use it for figuring out if I have thoriated tungsten or plain. Works like a champ. I know Ludlum has the same basic unit with different meter faces for the various ranges. I want to look into if somebody has like printable images you can lay over the standard CPM and mR/m face and will show micro sieverts or other nomenclature. I am mentally challenged when it comes to doing the conversions in my head. 20-Jan-20 09:28 AM it's better that way, as you can't determine dose(rate) with the 44-9 as is 20-Jan-20 09:28 AM there are filters aviable, but you lose alpha / beta capability with those 20-Jan-20 09:28 AM the magic ingredient is "Energy compensating" the gm, if you want to google more 20-Jan-20 02:21 PM I’m going to weigh in and disagree a little with spirit in that they should be calibrated at least to the extent of making sure the pulse rate displayed is approximately accurate. 20-Jan-20 02:28 PM Well, 1 pulse in = 1 pulse out is generally guaranteed unless your detector is very dead or very out of wack 20-Jan-20 02:35 PM Right but there is circuitry in the middle somewhere there before its displayed on an analog or digital gauge... I think his point is having that gauge read the counts properly, in the sense of digital it shouldn't need cal, but for analog gauge it could be off... 20-Jan-20 02:38 PM they're generally never off, but it's easy to test 20-Jan-20 02:38 PM feed in a square wave 20-Jan-20 03:57 PM I’ve run into ones that can be very off but I agree it is very easy to test so that’s why I recommend doing. 20-Jan-20 07:48 PM I know each detector varies in what excitation voltage is required for a specific actual firing. That probably should be adjusted for each new detector and it probably varies over time. It’s probably the sort of thing that just for general detector work it does not really matter but if it was part of a true radiation measurement system I would assume those would be calibrated regularly like any other test gear. 20-Jan-20 08:34 PM Most have a plateau 20-Jan-20 08:34 PM For dose rate measurement you do need calibration and energy compensation, but otherwise you don't 20-Jan-20 08:34 PM Most GM tubes have a range of voltages that don't really affect anything 20-Jan-20 10:46 PM why would ludlums not need any calibration? 20-Jan-20 10:46 PM ratemetering ludlums don't 20-Jan-20 10:46 PM they can do like 1k to 15k cpm full scale, and you can use whatever scale you want to 20-Jan-20 10:46 PM you can make them read really far off 20-Jan-20 10:47 PM well, yeah, it's an analog meter 20-Jan-20 10:47 PM as long as it reads the cpm you input, no other calibration is needed 20-Jan-20 10:47 PM that's like saying as long as a voltmeter reads the voltage you input you don't need to calibrate it 20-Jan-20 10:48 PM shhh 20-Jan-20 10:48 PM I mean there's nothing else to check 20-Jan-20 10:48 PM depends on how far you want to go, the high voltage can drift, the trigger setting can drift 20-Jan-20 10:50 PM thankfully they're simple meters and the documentation is available 21-Jan-20 06:38 AM my y88 synthesis worked 21-Jan-20 06:38 AM ill post the rates later this week 21-Jan-20 06:39 AM Hell yeah! 21-Jan-20 06:39 AM how exactly did you end up doing it? 21-Jan-20 06:50 AM molybdenum 88 decay series 21-Jan-20 06:50 AM Mo88 by B+ to 88Nb 21-Jan-20 06:50 AM 88Nb B+ to 88Zr 21-Jan-20 06:50 AM 88Zr EC to 88Y 21-Jan-20 06:51 AM and the Mo88 you got from breeding in your oven? 21-Jan-20 06:51 AM yup 21-Jan-20 06:51 AM im going to have several sources put together to make a more coherent source 21-Jan-20 06:51 AM awesome 21-Jan-20 06:51 AM (feel free to share pics ) 21-Jan-20 06:52 AM i will 22-Jan-20 03:20 AM oh boi 22-Jan-20 03:20 AM ooooh boi 22-Jan-20 03:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-14F32.png 22-Jan-20 03:20 AM guess what's on its way to me 22-Jan-20 03:50 AM <__ice9#6039> Heavy water electrolysis is a common method to produce it as needed also (needs desiccant tube afterward though) 22-Jan-20 03:50 AM <__ice9#6039> @Goldsteel oven? 22-Jan-20 03:56 AM spicy oven to bake things in 22-Jan-20 03:56 AM I know that heavy water is a good way to get it, but I want my fusor to be as easy to operate as possible, and wet chemistry is close to being the complete opposite to that 22-Jan-20 03:57 AM ? 22-Jan-20 03:57 AM by oven i assumed he meant neutron tank 22-Jan-20 04:00 AM <__ice9#6039> Oh for thermalization? 22-Jan-20 04:00 AM no 22-Jan-20 04:00 AM energy tuning 22-Jan-20 04:00 AM the water is mostly just for safety, since i have graphite sheets 22-Jan-20 04:01 AM <__ice9#6039> What is the original source? 22-Jan-20 04:01 AM its an AmBe source 22-Jan-20 04:01 AM <__ice9#6039> Ah I see 22-Jan-20 04:02 AM generally when i need a source i dont have, i try and find a decay series that can produce it 22-Jan-20 04:02 AM but unfortunately i can never make anything in a high enough activity to be of use outside of HPGe calibration 22-Jan-20 04:02 AM it turns out Y88 makes a very specific 1.8MeV gamma thats very creepily similar to a BSM gamma signal expected from exotic muon decays 22-Jan-20 04:02 AM so thats why i wanted it 22-Jan-20 04:10 AM <__ice9#6039> I remember being vaguely interested in these a while ago but lacking some of the background knowledge for the system components https://ipo.lbl.gov/lbnl1764/ 22-Jan-20 04:10 AM <__ice9#6039> I have much better RF equipment now though. 22-Jan-20 04:49 AM <__ice9#6039> However nowhere near enough time >____> 22-Jan-20 07:38 AM https://www.rollingstone.com/politics/politics-features/oil-gas-fracking-radioactive-investigation-937389/ 22-Jan-20 07:38 AM That's pretty terrifying 22-Jan-20 09:56 AM That is very interesting, never really thought about the radioelements getting bound up in the brine used in drilling. Wonder how much of an issue it is industry wide or if the problem is worse in certain geographic areas 22-Jan-20 10:58 AM According to that article, it depends on the geology in the place where drilling happens. As some are worse than others. 22-Jan-20 10:58 AM But the sediments with radium apparently happen everywhere. 22-Jan-20 10:58 AM The playground made from radioactive contaminated piping is something else. 22-Jan-20 10:58 AM Would have expected that from Soviet Russia 22-Jan-20 10:58 AM Not current day USA. 22-Jan-20 11:19 AM there are a lot of industrial hazards lurking around that most people know nothing about 22-Jan-20 11:19 AM friend of mine who did suction dredging gold mining up in central/northern california has a few pounds of mercury he sucked up out of the sediments heh found a hell of a lot more mercury than he did gold 22-Jan-20 11:19 AM at least mercury isnt radioactive though... 22-Jan-20 11:53 AM Gota be a power move to spray 13 thousand gallons of contaminated water on the dirt roads on a regular basis. 22-Jan-20 02:07 PM @Deleted User would you say that dosimeter you linked earlier would be a good starter alpha/xray detector or do you think there might be a better deal for my use case? 22-Jan-20 02:08 PM the "dosimeter" one? 22-Jan-20 02:08 PM https://www.ebay.com/itm/Dosimeter-Model-3100-Survey-Meter-with-Bicron-GI-LE-Probe/323743224389 22-Jan-20 02:08 PM yes, yes it is 22-Jan-20 02:08 PM perfect for starter and advanced 22-Jan-20 02:08 PM the G1LE is a suuupper nice probe 22-Jan-20 02:08 PM $130 is basically free for that kit 22-Jan-20 02:08 PM just beware, when you get it - the window under the cap is VERY fragile, and a single puncture means you get thallium sludge in a few days 22-Jan-20 02:08 PM oh lol looks like someone taped the cap on 22-Jan-20 02:08 PM (why would you do that, it's a low energy detector) 22-Jan-20 02:25 PM But between that and the fact it's showing a click count, safe to say it is intact at the time of the photos? 22-Jan-20 02:46 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200122_233438-1A4B4.jpg 22-Jan-20 02:46 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200122_233455-D6411.jpg 22-Jan-20 02:46 PM 12.75 Bq of natural uranium over 100 cm² 22-Jan-20 02:47 PM @Treehouseman yeah, CPM is fine 22-Jan-20 03:51 PM It's a nice pretty color at least 22-Jan-20 03:59 PM oh boi oh boi 22-Jan-20 03:59 PM cold clickety! 22-Jan-20 04:00 PM What is that check source? 22-Jan-20 04:00 PM heh, "check source" 22-Jan-20 04:00 PM https://www.youtube.com/watch?v=_NY0MTNRngY Bunch of those in a bag, containing Th232 22-Jan-20 04:01 PM Oh lol 22-Jan-20 04:02 PM was the first thing at hand that would not 100% flood the detector 22-Jan-20 04:06 PM start building those sharp spectra! 22-Jan-20 04:06 PM Look forward to seeing some x-ray spectroscopy with this thing! Are you expecting it to attain the original resolution? 22-Jan-20 04:06 PM heh, no x-ray stuff here 22-Jan-20 04:06 PM You do have pulse shaping amps and a MCA right? 22-Jan-20 04:07 PM spec starts at 40 kV and I'm damn sure I've lost some resolution in the lower end 22-Jan-20 04:07 PM well, the MCA is the issue 22-Jan-20 04:08 PM because of it being hot? 22-Jan-20 04:08 PM I have a canberra one but no software, I have some silena ones but no PC that can run the ancient stuff, I have some ortec ones but no ADCAM to USB cable, etc etc 22-Jan-20 04:08 PM Everyone needs a small lead castle in their home 22-Jan-20 04:08 PM oh that will come for sure 22-Jan-20 04:09 PM your radioisotope is in another castle! 22-Jan-20 04:10 PM your radioisotope is everywhere 22-Jan-20 04:10 PM oh god no 22-Jan-20 04:10 PM https://giphy.com/gifs/filmeditor-christmas-movies-bill-murray-3ohfFw6D2UMI6B2N7a 22-Jan-20 04:18 PM Does being warm for a while kill a HPGe's low energy sensitivity automatically? @Deleted User 22-Jan-20 04:19 PM I'm not sure 22-Jan-20 04:19 PM kindasorta 22-Jan-20 04:19 PM for P type it does, for N type it doesn't 22-Jan-20 04:19 PM and it doesn't kill it, it just lowers resolution 22-Jan-20 04:19 PM Oh, that's something to keep in mind for sure 22-Jan-20 04:19 PM well, "warm" is like 50-80°C 22-Jan-20 04:20 PM So you can't bake it? 22-Jan-20 04:20 PM I baked my detector at 70°C for 24h 22-Jan-20 04:21 PM is yours n or p? 22-Jan-20 04:22 PM regular p 22-Jan-20 04:22 PM how does it kill the sensitivity? 22-Jan-20 04:22 PM no wait was p type or n type the regular one 22-Jan-20 04:22 PM http://www.gammadata.se/assets/Uploads/SEGe-detectors-C49317.pdf 22-Jan-20 04:22 PM that's mine 22-Jan-20 04:22 PM because the Li drifts inside and the passive volume grows 22-Jan-20 04:23 PM HPGe or GeLi? 22-Jan-20 04:23 PM HPGe 22-Jan-20 04:24 PM I thought it didn't use Li 22-Jan-20 04:24 PM they still use Li electrodes / contacts, but aren't doped with it 22-Jan-20 04:24 PM Although Ge detectors can be warmed up when not in use, the lithium-diffused N+ contact is not perfectly stable at room temperature. For this reason it is best to avoid extended warm time, especially for standard-electrode coaxes where the Li contact affects low energy response. 22-Jan-20 04:24 PM https://www.aps.anl.gov/files/APS-Uploads/DET/Detector-Pool/Spectroscopic-Detectors/Canberra/Germanium_Detectors_Manual.pdf 22-Jan-20 04:24 PM well 22-Jan-20 04:24 PM I should have gone to bed three hours ago 22-Jan-20 04:24 PM but you know how it goes 22-Jan-20 04:24 PM good night 22-Jan-20 04:28 PM Good night! 23-Jan-20 01:14 AM Oh my, I don't even have an mca on there yet and can already see the lines of my samples 23-Jan-20 01:40 AM https://www.youtube.com/watch?v=QdHXeiVxivQ 23-Jan-20 03:55 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-24962.jpg 23-Jan-20 03:55 AM You might be wondering why I’m using this 23-Jan-20 03:55 AM This is why 23-Jan-20 03:55 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-42B2E.jpg 23-Jan-20 03:55 AM There is nothing else after discrimination 23-Jan-20 03:57 AM looks like maestro 23-Jan-20 03:57 AM It is 23-Jan-20 03:57 AM why is your peak sloped to the left? 23-Jan-20 03:57 AM scattering? 23-Jan-20 03:57 AM It’s not really 23-Jan-20 03:57 AM But I would assume so 23-Jan-20 03:58 AM kinda looks like it is 23-Jan-20 03:58 AM It’s not a tail so it must be scattering 23-Jan-20 03:59 AM Anyways, congrats! 23-Jan-20 04:03 AM The next stop is subjecting it to high intensity 23-Jan-20 04:03 AM At ELBE 23-Jan-20 04:03 AM the poor detector :< 23-Jan-20 04:03 AM wait you're in germany? 23-Jan-20 04:04 AM Oh yeah 23-Jan-20 04:04 AM It’s gonna burn 23-Jan-20 04:04 AM No I’m not 23-Jan-20 04:04 AM too bad 23-Jan-20 04:07 AM I have to subject this detector to muon irradiation 23-Jan-20 04:07 AM So I need to verify how it performs in every circumstance 23-Jan-20 04:07 AM Efficiency curves 23-Jan-20 04:07 AM Performance curves 23-Jan-20 04:07 AM How rate affects things 23-Jan-20 04:09 AM so you're looking for some gammas in muon decay? 23-Jan-20 04:09 AM according to wiki there is a 1.4 +/- 0.4% chance of a photon, I assume that's your 1.8 MeV gamma 23-Jan-20 04:09 AM what exactly are you / the researchers you work with trying to figure out? 23-Jan-20 05:20 AM https://gigabecquerel.wordpress.com/2020/01/23/canberra-hpge-repair-part-3-3/ 23-Jan-20 06:56 AM We aren’t strictly observing the decay gammas 23-Jan-20 06:56 AM We are observing the interaction with target matter 23-Jan-20 06:56 AM Which sometimes emits (in theory) neutrinoless gamma 23-Jan-20 06:56 AM I’m trying to make a glorified gamma counter for the stopping target monitor 23-Jan-20 06:56 AM I can currently handle about 50kHz before my electronics poop out 23-Jan-20 06:56 AM So I’m probably going to order new preamps 23-Jan-20 06:56 AM The 1.8MeV is actually an aluminium decay 23-Jan-20 06:56 AM We use different muon stopping materials 23-Jan-20 06:56 AM Aluminium, gold, lead, tin 23-Jan-20 06:56 AM They all have unique decay series but aluminium has pretty distinct ones that can be easily told apart from a BSM decay 23-Jan-20 06:56 AM I’m basically looking to form muonic atoms 23-Jan-20 06:56 AM And those muonic atoms should decay certain ways 23-Jan-20 06:56 AM But since muons are so heavy they have a higher cross section for low probability events in new physics 23-Jan-20 06:56 AM So it lets us precisely constrain new theories by rejecting indirect evidence of new decays 23-Jan-20 06:56 AM This goes hand in hand with the sister experiment 23-Jan-20 06:56 AM Where the magnetic moment of the muon is the scattering case 23-Jan-20 06:56 AM I am looking at the decay case 23-Jan-20 06:56 AM You just rotate the Feynman diagram 90 degrees 23-Jan-20 06:56 AM We have slight disagreements in physical constants that may be because things are wrong 23-Jan-20 07:17 AM oh, ok 23-Jan-20 07:17 AM reminds me of the last time I met a particle physicist, he was like "Nuclear physics? Eh that's basically chemistry" 23-Jan-20 07:56 AM Oh dear 23-Jan-20 07:56 AM Well I am a particle physicist 23-Jan-20 07:56 AM But most of us just code stuff and sit in the ivory tower 23-Jan-20 07:56 AM It ceases to become scientific content when all you do is work with big data for machine learning 23-Jan-20 07:56 AM It feels very empty 23-Jan-20 08:00 AM I can imagine 23-Jan-20 08:00 AM that's why I want to do detector physics, work with the "real thing" 23-Jan-20 08:00 AM 'tho I can already see this turning into days and days of efficiency calculations... 23-Jan-20 08:27 AM Yup 23-Jan-20 09:09 AM quickly threw something together... Looks terrible, but still worlds better than NaI(Tl)! 23-Jan-20 09:09 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2E675.png 23-Jan-20 09:45 AM and now with some tweaking 23-Jan-20 09:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D8672.png 23-Jan-20 10:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8CF98.png 23-Jan-20 10:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/EO_LstSX0AAYGrH-07F25.png 23-Jan-20 12:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200123_203842-9F9DC.jpg 23-Jan-20 12:01 PM Is it ok if it sits vertically? 23-Jan-20 12:02 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200123_205842-5C0B5.jpg 23-Jan-20 12:02 PM well it should be 511 keV, but in the end it still is just theremino... 23-Jan-20 12:02 PM calibration is still required 23-Jan-20 12:02 PM but 511 vs 513 seems like a DC offset of the sound card 23-Jan-20 12:02 PM a few mV 23-Jan-20 12:04 PM sure, it can even look straight down and be just fine 23-Jan-20 12:04 PM yeah I didn't do any fine cal, but it's within +/- 2 keV for the most part 23-Jan-20 12:40 PM https://gigabecquerel.wordpress.com/2020/01/23/first-gamma-spectra/ 23-Jan-20 01:25 PM Cool! 23-Jan-20 03:04 PM https://www.amazon.com/gp/product/B06XP5R449 23-Jan-20 03:04 PM Something cheap like this can improve Theremino performance by quite a bit 23-Jan-20 03:04 PM 24 bit resolution is likely better than anything that comes stock with your computer 23-Jan-20 03:10 PM oh I already fiddeled with the pulseshaping and am getting way better results now 23-Jan-20 03:10 PM but thanks ^^ 23-Jan-20 03:10 PM so far nothing is above 2.2% FWHM 23-Jan-20 03:10 PM but with so much resolution it takes theremino aaaages to build a nice spectrum, thanks to its rate limit 23-Jan-20 03:13 PM HPGe deserves better than Theremino, but I think it's a nice system considering just how cheap you can throw everything together 23-Jan-20 03:13 PM oh that's for sure 23-Jan-20 03:13 PM but I just don't have a better MCA yet 23-Jan-20 03:13 PM I repaired this detector and theremino is a dirt cheap way to test it 23-Jan-20 03:16 PM Where did you find your broken HPGe by the way? That amazing scrapyard of yours? 23-Jan-20 03:18 PM heh, I wish 23-Jan-20 03:18 PM no, I swapped it for another detector 23-Jan-20 03:18 PM I was told it works, but I guess being able to write "repaired a HPGe in his basement" on your resume actually is an upside 23-Jan-20 03:22 PM That's for sure. I'd like to start getting some fast neutron detectors. Might get a chance to grab some lithium glass scintillators soon 23-Jan-20 03:23 PM why fast? 23-Jan-20 03:23 PM as in: Why not slow + moderator? 23-Jan-20 03:23 PM Time of flight 23-Jan-20 03:23 PM I can use He-3 tubes in a pinch but the sensitivity is just too low 23-Jan-20 03:23 PM And also I'd like to build an indium neutron activation counter 23-Jan-20 03:24 PM ohh, nice 23-Jan-20 03:24 PM In quantity the indium is actually cheaper than silver 23-Jan-20 03:24 PM try some BC412 that works wonders with fast neutrons 23-Jan-20 03:26 PM I think it'll be harder to do gamma neutron discrimination with plastic scintillators right? 23-Jan-20 03:27 PM depends on your gamma background, but generally you can do some simple pulse height analysis 23-Jan-20 03:27 PM plus the 412 is blind below 100 keV 23-Jan-20 03:30 PM That is nice, when I need it, I'll grab a cylinder of BC412 just to try out. I think high energy gammas won't be a big issue for me 23-Jan-20 03:30 PM The main problem is really that x-rays from Bremsstrahlung can have a pretty long tail in my experiment 23-Jan-20 03:31 PM plus you can intrinsically discriminate them by using a small / flat cylinder 23-Jan-20 03:32 PM But then I do make sacrifices to detector efficiency 23-Jan-20 03:32 PM yep 23-Jan-20 03:33 PM I need a pretty big volume, if the detector is far away 23-Jan-20 03:33 PM And then there's a trade-off again with TOF resolution 23-Jan-20 03:33 PM do you need a big volume or a big area of detection? 23-Jan-20 03:33 PM Big area of detection yeah 23-Jan-20 03:33 PM => film 23-Jan-20 03:33 PM They make these scintillators in film/super thin sheets? 23-Jan-20 03:34 PM they sure do 23-Jan-20 03:34 PM Hmm, I'll look out for them 23-Jan-20 03:34 PM But most likely the cylinders on eBay will be good enough 23-Jan-20 03:34 PM Especially because they fit photomultipliers easily 23-Jan-20 03:35 PM most contamination (as in: big area >100 cm²) detectors are foil scintillators 23-Jan-20 03:35 PM How do they couple the light then? 23-Jan-20 03:35 PM big-arse piece of acrylic and some SiPMs 23-Jan-20 03:36 PM Must be a heck of a lot of SiPMs 23-Jan-20 03:36 PM When will they come down in price 23-Jan-20 03:36 PM it's not that bad 23-Jan-20 03:36 PM the amount I mean, not the price 23-Jan-20 03:36 PM AFAIK a lot of the contamination monitors are just giant chunks of scint plastic 23-Jan-20 03:37 PM Oh I guess they design the acrylic light guide in some clever ways 23-Jan-20 03:37 PM yep 23-Jan-20 03:37 PM and they don't need to be perfect, as you're not doing any spectroscopy and plastics are generally quite bright 23-Jan-20 03:38 PM there was a set of huge scint plastic detectors on ebay a while ago 23-Jan-20 03:38 PM I think they were over a meter long 23-Jan-20 03:38 PM Yellowed plastic? 23-Jan-20 03:38 PM 30-40cm wide 23-Jan-20 03:38 PM plastic doesn't yellow 23-Jan-20 03:38 PM you're thinking of NaI:Tl and CsI:Tl 23-Jan-20 03:38 PM Oh sorry, yeah, I confused them 23-Jan-20 03:39 PM oh it's still up 23-Jan-20 03:39 PM https://www.ebay.com/itm/Bicron-BC412-42-X-12-X-2-1-4-Scintillator-Plastic-w-Scintillation-Detector/283446590006 23-Jan-20 03:44 PM Considering the size and that it comes with a PMT and power supply, price is not too bad 23-Jan-20 03:44 PM Aye 23-Jan-20 03:45 PM But yeah, it's a little too big 23-Jan-20 03:45 PM stuff it in your wall 23-Jan-20 03:45 PM get out the hacksaw 23-Jan-20 03:45 PM anyone walking through the door gets a free rad screening 23-Jan-20 03:45 PM this thing will smell a smoke detector in your pocket 23-Jan-20 03:45 PM lol 23-Jan-20 03:45 PM no it won't 23-Jan-20 03:45 PM BC412 is absolutely 100% blind to americium 23-Jan-20 03:46 PM is it? 23-Jan-20 03:46 PM hm 23-Jan-20 03:46 PM pretty steep cutoff below 100 keV 23-Jan-20 03:46 PM well, I guess it could detect the lower energy stuff 23-Jan-20 03:46 PM oh 23-Jan-20 03:46 PM ABOVE 23-Jan-20 03:46 PM This is very very good in my case 23-Jan-20 03:47 PM doesn't even see 70 kV x-rays 23-Jan-20 03:47 PM I need to discriminate against low energy ionization line radiation and bremsstrahlung x-rays, which would blind most scintillators in a pulse 23-Jan-20 03:48 PM maybe it could see Am-241's 97kev 0.02% line 23-Jan-20 03:48 PM lol 23-Jan-20 03:50 PM Do you think all the outer surfaces of the block will be suitable for coupling to scintillators 23-Jan-20 03:50 PM if not you can easily polish it 23-Jan-20 03:50 PM Like I'm seriously thinking about cutting this massive block up 23-Jan-20 03:50 PM behaves like hard pvc 23-Jan-20 03:50 PM The block is the scintillator 23-Jan-20 03:52 PM It's much more practical for me if I can have 4 or 5 smaller blocks each with a PMT at different distances 23-Jan-20 03:52 PM if you cut it off carefully and polish, it will work 23-Jan-20 03:52 PM Do I need to lap the surface? 23-Jan-20 03:52 PM nope 23-Jan-20 03:52 PM Meaning does it need to be super flat? 23-Jan-20 03:52 PM just polishing on glass 23-Jan-20 03:52 PM Okay 23-Jan-20 03:52 PM just polish it to like 2000 grid 23-Jan-20 03:52 PM Oh, surprisingly low 23-Jan-20 03:52 PM coupling gel will do the rest 23-Jan-20 03:52 PM I'd go a bit higher 23-Jan-20 03:52 PM but yeah you need optical silicone goop 23-Jan-20 03:52 PM And yeah, use optical grease 23-Jan-20 03:53 PM oh and keep in mind to keep it away from alkanes, and don't couple it with vaseline etc 23-Jan-20 03:53 PM that will make the surface swell and crack, I've had great results with the DC vacuum grease 23-Jan-20 03:54 PM I've got some BC-600 optical cement 23-Jan-20 03:55 PM don't have any experience with that 23-Jan-20 03:55 PM Uh oh... 23-Jan-20 03:56 PM oh? 23-Jan-20 03:56 PM Why you do this to me? 23-Jan-20 03:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A0E2F.png 23-Jan-20 03:56 PM well 23-Jan-20 03:56 PM I'll try silicone vacuum grease 23-Jan-20 03:56 PM If I decide to get that block in the future 23-Jan-20 03:57 PM you do 23-Jan-20 03:57 PM anyway, gonna go to bed now 23-Jan-20 03:57 PM the hpge is running, let's see how my spectrum will look tomorrow 23-Jan-20 03:57 PM ugh I gotta go to the dentist in looks at watch 8 hours >.< 23-Jan-20 03:57 PM getting two (non superconducting) cavities filled 23-Jan-20 03:57 PM but maybe that's a good excuse to spend all day long in the basement and not talk to anyone 23-Jan-20 03:57 PM Good night 23-Jan-20 04:00 PM You can still type! 23-Jan-20 04:01 PM I meant talk-talk 23-Jan-20 04:01 PM no one in my house is interested in physics 23-Jan-20 08:50 PM I was born lucky to a physicist father, but these days all he wants to talk about is politics >< 23-Jan-20 11:52 PM Spectrum! 23-Jan-20 11:52 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-FA618.png 23-Jan-20 11:59 PM now those are very sharp peaks 24-Jan-20 12:10 AM some day someone will discover a room temperature detector with HPGe levels of FWHM resolution 24-Jan-20 12:10 AM and then all the other detectors will become obsolete 24-Jan-20 12:56 AM not sure where the most applicable place for this would be but i am assuming it might fit in here... 24-Jan-20 12:56 AM any guesses on the intended uses of this as manufactured? 24-Jan-20 12:56 AM https://www.ebay.com/itm/Beryllium-Metal-Element-Sample-112-g-Machined-Part-99-9-Pure-Periodic-Table/372685759130 24-Jan-20 12:56 AM listing says gyroscopes but beryllium seems like overkill in that application 24-Jan-20 01:04 AM It's aerospace, overkill is the motto there 24-Jan-20 01:07 AM true i just have only ever seen the spheres from those...what could a 112g chunk of beryllium be used for in a gyroscope? the geometry of that just doesnt make any sense for that to me 24-Jan-20 01:09 AM maybe the actual gyro is inside and this is just the housing 24-Jan-20 01:09 AM Part of the gimbal 24-Jan-20 04:42 AM oh jeez 24-Jan-20 04:42 AM I just got a mail from ortec 24-Jan-20 04:42 AM "we often get old electronics from our customers, if you want we can send you some" 24-Jan-20 05:37 AM "YES PLEASE" 24-Jan-20 05:37 AM also rip your storage space 24-Jan-20 05:49 AM "thank you for your offer, but no thank you, I think my workshop is full enough, and I don't want to overdo it" 24-Jan-20 07:28 AM lol 24-Jan-20 09:59 AM what kind of old electronics 24-Jan-20 10:03 AM I have no idea 24-Jan-20 10:03 AM but he was asking if I have a nim bin, HVPS and amps, so I assume either NIM stuff or stuff that works with NIM 24-Jan-20 10:03 AM I told him I'll take as much as I can, doesn't matter if it's broken 24-Jan-20 11:51 AM well dang 24-Jan-20 11:51 AM if ortec's just handing out old kit i might have to give their local offices a ring.. 24-Jan-20 11:51 AM forget paying $20/module on fleabay 24-Jan-20 11:51 AM whaaa 24-Jan-20 11:51 AM where the hell do you find them for that cheap 24-Jan-20 11:51 AM XD 24-Jan-20 11:51 AM all the ones here are 100+ 24-Jan-20 11:52 AM alright in fairness the actually useful ones are like twice+ that 24-Jan-20 11:52 AM but sometimes i've found interesting/bespoke modules for about that much, where the seller either has no idea what it's for, or knows what its for and knows that it's nigh-useless 24-Jan-20 11:52 AM i have a 2U NIM module with a tiny adorable bell on the front and some toggle switches and high speed mercury-wetted relays, i think it was from some weird super-early networked computer system at lawrence berkeley labs called 'MIDAS' 24-Jan-20 11:52 AM i can't find much detail on it 24-Jan-20 11:52 AM but the module was like, $30 24-Jan-20 11:55 AM oh man 24-Jan-20 11:55 AM I want a thing that goes ding 24-Jan-20 11:55 AM hmm, look for a rare event and hook up your sca to the bell 24-Jan-20 11:56 AM exactly :D 24-Jan-20 11:56 AM wanted to hook it up to a neutron counter 24-Jan-20 11:56 AM so if i ever get some deuterons zinging around at speed, i get a nice audible ruckus 24-Jan-20 11:57 AM and depending on count rate the signal goes either to a small bell, a horn or an air raid siren 24-Jan-20 11:57 AM but hey, so far I got nothing from ortec, so let's wait and see what happens 24-Jan-20 11:59 AM ^^ 24-Jan-20 11:59 AM 'tho tbh I don't think they will give away detectors 24-Jan-20 11:59 AM would be too nice 24-Jan-20 11:59 AM but hey, now that I've got a proper gamma spec setup (apart from the MCA, that's still just my soundcard) I can also get my alpha going 24-Jan-20 12:02 PM 'GM tube for your thoughts?' 24-Jan-20 12:02 PM yeah, congrats on that btw :D 24-Jan-20 12:02 PM thanks 24-Jan-20 12:03 PM now i get to figure out my own detector refilling/refurbing adventures 24-Jan-20 12:03 PM been swamped with work and furry shenanigans 24-Jan-20 12:03 PM also sometime next week i oughta make the trek up to berkeley's libraries and see if i can dig up any info on MIDAS 24-Jan-20 12:03 PM https://books.google.com/books?id=f0DL1VZB-44C&pg=PA20&lpg=PA20&dq=MIDAS+lbl&source=bl&ots=PxQlGWC0cG&sig=ACfU3U30yrooN63GwUbkSTRlfoH5VF2ahQ&hl=en&sa=X&ved=2ahUKEwjYyu6dg53nAhUFvZ4KHekVBz4Q6AEwA3oECAkQAQ#v=onepage&q=MIDAS%20lbl&f=false 24-Jan-20 12:03 PM i'm curious again 24-Jan-20 12:04 PM detector refilling? 24-Jan-20 12:04 PM and i kinda don't want to dismantle a little piece of history 24-Jan-20 12:04 PM (but i also really do) 24-Jan-20 12:04 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200124_210316-4713A.jpg 24-Jan-20 12:04 PM er, not refilling, but vacuum purging i guess 24-Jan-20 12:04 PM antifilling 24-Jan-20 12:04 PM ahh, pulling the plug and filling in a bottle of vacuum 24-Jan-20 12:04 PM did you get some ln2 yet? 24-Jan-20 12:06 PM nah, need a transport dewar first 24-Jan-20 12:06 PM gotta go shopping 24-Jan-20 12:06 PM also it may be that the detector and dewar have separate vacu...a(?) and that hte dewar is just fine 24-Jan-20 12:06 PM how are transport dewar prices ar your place? here they're horrendously expensive 24-Jan-20 12:06 PM maybe look for an old, broken Ge(Li) detector or the likes and use its dewar, they're like a 30l standard size 24-Jan-20 01:03 PM I wonder if it's possible to "undrift" Li from all the detectors 24-Jan-20 01:04 PM undo diffusion? 24-Jan-20 01:04 PM you'd need one hell of a maxwell demon for that 24-Jan-20 01:14 PM heh 24-Jan-20 01:43 PM I was thinking about un-drifting detectors by placing something next to them that... I don't know, creates a "drift hole"? 24-Jan-20 01:43 PM So that the lithium drifts into this sacrificial bit of whatever, and presumably out of the detector 24-Jan-20 01:44 PM so is lithium coming out of the detector? so accelerating diffusion out of it? 24-Jan-20 01:44 PM could just heat it back up if that's what you want.. 24-Jan-20 01:46 PM with GeLi it drifts in 24-Jan-20 01:46 PM while i don't know how feasible the process is if it's already diffused out once, the process for drifting Li into Si/Ge seemingly involves a long hot sit in a Li-rich atmosphere 24-Jan-20 01:46 PM ohh 24-Jan-20 01:46 PM same with SiLi, but SiLi can survive sitting warm 24-Jan-20 01:47 PM so... place a HPGe next to a GeLi, hoping the HPGe will take the Li and "undrift" the geli? 24-Jan-20 01:47 PM ... something like that? 24-Jan-20 01:47 PM Except probably not extremely expensive HPGe 24-Jan-20 01:47 PM just Ge 24-Jan-20 01:48 PM diffusion goes both ways, if you use unpure Ge you will get unpure (ex)GeLi 24-Jan-20 01:48 PM Ge can be pretty pure 24-Jan-20 01:48 PM Like thermal imaging lens monocrystal pure 24-Jan-20 01:48 PM But not ultrapure 24-Jan-20 01:48 PM GeLis are pretty pure 24-Jan-20 01:49 PM Man, someone really needs to figure out czochralski at home 24-Jan-20 01:49 PM please 24-Jan-20 01:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/3-Figure1-1-A5DE2.png 24-Jan-20 01:50 PM yep 24-Jan-20 01:50 PM Temptingly simple looking 24-Jan-20 01:50 PM I suppose "just czochralski" is easy 24-Jan-20 01:50 PM Melt a thing in a controlled atmosphere, put a spinny solid thing into the molten thing, and pull 24-Jan-20 01:50 PM But process control is where the fun begins 24-Jan-20 01:53 PM maybe an old rig will end up on ebay one day 24-Jan-20 01:57 PM rigs from the 70ies are being retrofitted 24-Jan-20 01:59 PM http://web.mit.edu/8.13/8.13d/manuals/canberra/canberra-ge-gamma-spectrometer-systems.pdf 25-Jan-20 10:27 AM Got a pretty decent nuclear spectroscopy setup now, high rez Alpha and gamma ️ 25-Jan-20 10:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200125_191244-CEB84.jpg 25-Jan-20 10:35 AM <__ice9#6039> Impressive 25-Jan-20 10:36 AM only thing missing is a good mca 25-Jan-20 10:36 AM but I'm working on that! 25-Jan-20 02:08 PM Speaking of MCA, I just tried BecqMoni 25-Jan-20 02:08 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1D706.png 25-Jan-20 02:08 PM tbh this almost feels like a real MCA, and I get so much more resolution than with theremino 25-Jan-20 02:08 PM keep in mind this is all just over the internal soundcard of my workshop pc 25-Jan-20 02:14 PM Tuning BecqMoni is hell, but once you get it down, it's a really awesome tool 25-Jan-20 02:14 PM Shame it's not opensource 25-Jan-20 02:14 PM If someone speaks Japanese, could be worth trying to contact kabuworkman to see if they'll share the source code 25-Jan-20 05:17 PM The new counter arrived and seems to work just fine 25-Jan-20 05:17 PM Though I think I need to check the battery voltage 25-Jan-20 05:17 PM Looks like a metal window on this one and not mica 25-Jan-20 05:17 PM So I would assume beryllium? 25-Jan-20 05:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200125_202937-77736.jpg 25-Jan-20 05:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200125_204314-C2CEB.jpg 25-Jan-20 06:21 PM @Treehouseman it's very thin aluminium IIRC 25-Jan-20 06:21 PM this detector is pretty blind to high energies because it has a very thin NaI:Tl disk directly behind that window 25-Jan-20 06:21 PM (not sealed) 25-Jan-20 06:40 PM this just got a bit interesting, and it looks like I'm definitely going to pick up some 9v batteries in the morning 25-Jan-20 06:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200125_214048-F8DE6.jpg 25-Jan-20 06:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200125_214057-022B1.jpg 25-Jan-20 06:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200125_214109-17CD8.jpg 25-Jan-20 06:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200125_214119-0A692.jpg 25-Jan-20 06:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200125_214130-0804E.jpg 25-Jan-20 08:37 PM https://youtu.be/17cwyZzxx6g 25-Jan-20 08:53 PM Now that I think about it, that might be beryllium 25-Jan-20 08:53 PM (which makes it cooler, not worse) 25-Jan-20 09:56 PM Flipping the switch inside does cause it to start giving dose measurements instead of click measurements 25-Jan-20 09:56 PM I need to get dumps of the eprom and eeprom 25-Jan-20 10:07 PM I doubt it's going to give you a real dose measurement 25-Jan-20 10:07 PM since it's not energy compensated 25-Jan-20 10:07 PM but CPM/CPS is useful 25-Jan-20 10:07 PM reminds me of this dingus 25-Jan-20 10:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/electra_001-5AF49.png 25-Jan-20 10:07 PM Also see #swap-meet for a neat deal 26-Jan-20 12:05 AM very nice ratemeter you got there @Treehouseman 26-Jan-20 12:05 AM the autoranging sounds like hiccups 26-Jan-20 03:12 AM <__ice9#6039> @GigaSquirrel thanks for the reference to BecqMoni. Does it work with the theremino hardware? 26-Jan-20 03:14 AM I mean the theremino hardware is just a usb soundcard 26-Jan-20 03:14 AM so I assume yes 26-Jan-20 04:15 AM I have this one https://www.gammaspectacular.com/blue/gamma-spectroscopy/sound-card-spectrometry-drivers/gs-usb-pro for my 63*63 NaI, and it is a joy to work with compared to my previous DIY voltage source and amplifier. Detected as USB sound card too. Now I want to try HPGe with it, the question though is where do I find HPGe... 26-Jan-20 05:02 AM there are a few on ebay for ~1.5k 26-Jan-20 05:02 AM but it's a gamble 26-Jan-20 07:26 AM where radiation makes you always smile 28-Jan-20 03:08 AM Has anone here done xrf with NaI? 28-Jan-20 03:08 AM http://physicsopenlab.org/2016/02/24/diy-xrf-spectrometry/ 28-Jan-20 03:08 AM because this doesn't look very promosing tbh 28-Jan-20 03:13 AM I totally would 28-Jan-20 03:14 AM and I was wondering if that's the physical limitation of the method or if that's because of this setup 28-Jan-20 03:15 AM yeah what xtals are best? 28-Jan-20 03:15 AM randomly ordering scintillator crystals 28-Jan-20 03:17 AM do you have a broad collection of scintillators? 28-Jan-20 03:18 AM not very broad 28-Jan-20 03:18 AM NaI(Tl), CsI and some plastic 28-Jan-20 03:18 AM NaI should work, CsI not, and plastic isn't made for spectroscopy anyways 28-Jan-20 03:18 AM CsI gives off 2 photons per keV, spectroscopy below 20 keV would be fun with that XD 28-Jan-20 03:19 AM those usb gamma spectrometer @ZeptoBars have 16 bit and 48kHZ?? 28-Jan-20 03:19 AM yeah it's just a Soundcard 28-Jan-20 03:20 AM ah ok 28-Jan-20 03:20 AM PCM2902? 28-Jan-20 03:20 AM the old audio2usb codec 28-Jan-20 03:20 AM but ok thats not what costs the money I no 28-Jan-20 03:20 AM know 28-Jan-20 03:23 AM nothing about the theremino hardware justifies the cost 28-Jan-20 03:23 AM yeah well the engineering!!!11 28-Jan-20 03:24 AM it's a sound card, a ccfl Inverter and some off the shelf opamps 28-Jan-20 03:24 AM yep 28-Jan-20 03:24 AM hmm is it easy to make NaI crystals? 28-Jan-20 03:26 AM 'tho I gotta say Soundcard spectroscopy works better than expected 28-Jan-20 03:26 AM should be fairly easy if you have a Czochralski setup 28-Jan-20 03:32 AM yeah ehehe hmmm 28-Jan-20 03:32 AM is there a feasible way for distributed amateur detection of those beteigeusian neutrinos? 28-Jan-20 03:32 AM I mean with the powaz of intense statistics :)) 28-Jan-20 03:42 AM regular neutrino detectors already use intense statistics 28-Jan-20 03:42 AM there really isn't a good way to detect neutrinos in a small volume 28-Jan-20 03:42 AM small as in "not the size of a house" 28-Jan-20 03:50 AM yeah 28-Jan-20 04:00 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200128_125148-FBA99.jpg 28-Jan-20 04:00 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200128_125244-5D541.jpg 28-Jan-20 04:09 AM Xrf with nai works if you use a really thin slice of it 28-Jan-20 09:44 AM anyone have a specific usb sound card for use with theremino/that sort of MCA? or can i just use the onboard sound card in my computer without too much issue? 28-Jan-20 09:44 AM i am just happy that it seems like the PMT in my NaI setup seems like it still works, must have been an issue with the voltage divider 28-Jan-20 10:04 AM I've had the best results with my pcs internal Soundcard 28-Jan-20 10:20 AM just wanted to make sure that i would not be handicapping myself doing that 28-Jan-20 10:22 AM https://www.fingers-welt.de/phpBB/download/file.php?id=25191&mode=view 28-Jan-20 10:22 AM that was done with the soundcard 28-Jan-20 10:22 AM of a dell optiplex 755 28-Jan-20 10:22 AM but not NaI tho 28-Jan-20 10:51 AM not my greatest soldering job but i am pretty happy i managed to squeeze the BNC connector into the original housing https://i.gyazo.com/6a7bac4300b83fc48bac2f515d9bb783.jpg 28-Jan-20 10:51 AM its one of the Scionix 38B57 scintillators that showed up on ebay a few years ago for around $70 28-Jan-20 10:51 AM came with some weird voltage divider with transistors on it that most people just remove 28-Jan-20 10:53 AM oh, that's the extra stabilized / regulated version 28-Jan-20 10:53 AM makes the actual HVPS way simpler 28-Jan-20 10:54 AM i still have the original voltage divider somewhere if i decide to try reusing it 28-Jan-20 10:54 AM any idea what this might have been used in based on the back cap https://i.gyazo.com/4b7812cde8fa9e036ab2fbe56b295acf.png 28-Jan-20 10:56 AM 6.7% is the resolution 28-Jan-20 10:56 AM the rest is not very legible 28-Jan-20 10:57 AM yes i know that, was just hoping the rest of it might be recognizable to someone 28-Jan-20 10:57 AM 280 mV is the output at a certain energy, 662 keV I bet 28-Jan-20 10:57 AM likely also the resolution at that energy 28-Jan-20 11:08 AM https://www.amazon.com/gp/product/B06XP5R449 28-Jan-20 11:08 AM I've posted this before, but I've had good luck with this usb sound card for use with Theremino @LRM 28-Jan-20 11:19 AM definitely need to work on settings and stuff but it seems like it is definitely workingish 28-Jan-20 11:19 AM need to reread everything i have forgotten about the settings i suppose 28-Jan-20 11:19 AM https://i.gyazo.com/0c1c03178cc16fcb0ae9500fe5104ab7.png 28-Jan-20 11:19 AM black line is a quick background measure 28-Jan-20 11:19 AM green is an even quicker measure on some radioactive petrified wood 28-Jan-20 11:21 AM thanks for the reminder, I have some of that wood as well and should take a spectrum 28-Jan-20 11:23 AM ive got a bunch of random petrified wood because my grandpa was a rockhound for most of his life, not as much was radioactive as i expected 28-Jan-20 11:23 AM also discovered when i got a geiger counter a few years ago that there was a pitchblende sample in a box he gave me that none of us knew about heh 28-Jan-20 11:36 AM https://i.gyazo.com/26217870db3eb4e2fdba26b717f6f14c.png 28-Jan-20 11:36 AM background vs pitchblende 28-Jan-20 11:36 AM you need more gain 28-Jan-20 11:36 AM just turn up your microphone volume in sound settings 28-Jan-20 11:37 AM yup 28-Jan-20 11:37 AM I'd go for becqmoni too 28-Jan-20 11:37 AM if i go up much more it starts clipping on the little VU meter 28-Jan-20 11:38 AM that's not an issue 28-Jan-20 11:38 AM theremino just really likes to complain 28-Jan-20 11:38 AM ahhh okay 28-Jan-20 11:38 AM the most recent becqmoni is from 2014 it seems? and just in japanese? this might be fun... 28-Jan-20 11:40 AM nah it's mostly english 28-Jan-20 11:40 AM just compare 28-Jan-20 11:40 AM theremino 28-Jan-20 11:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1-55872.png 28-Jan-20 11:40 AM becqmoni 28-Jan-20 11:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-BF540.png 28-Jan-20 11:40 AM also the energy calibration of Bq is so much better 28-Jan-20 11:40 AM got it down to 200 eV 28-Jan-20 11:48 AM hmm becqmoni is tossing all the pulses, maybe things are not as close to working as i thought 28-Jan-20 11:48 AM you need to tweak it to not toss them 28-Jan-20 11:48 AM have you "trained" it? 28-Jan-20 11:48 AM and that 28-Jan-20 11:48 AM nope, just hooked it up and figured i would see if it just worked right off the bat, will go read the manual and stuff in a little bit 28-Jan-20 11:53 AM it's a bit of a pain to set up 28-Jan-20 02:43 PM finished up some stuff and have a few minutes to look at this some more...is there any easy way to ID the number of ADC channels on my sound card? not finding any information on it in my hardware info and i am just on my laptop so it is not like it is a physical card or anything 28-Jan-20 02:44 PM lol, there is none 28-Jan-20 02:44 PM that's all in software 28-Jan-20 02:44 PM for NaI go with 2k or 4k 28-Jan-20 02:47 PM okay, will stick with 2k because i have not had anything going in the bins over that anyway 28-Jan-20 02:48 PM Got a spectrum for us? ^^ 28-Jan-20 03:40 PM had to take care of something on the phone but ran a couple things while doing that, in blue is background, grey is the pitchblende https://i.gyazo.com/2ed43ae92e5dc7b0bdb38b5b149be698.png 28-Jan-20 03:40 PM have not tried to do any of the calibration yet 28-Jan-20 03:40 PM amazing how high the count rate is for it even with the chunk like 2-3inches away from the end of the detector, something like 1600 cps according to becqmoni 28-Jan-20 04:09 PM that seems a bit high 28-Jan-20 04:09 PM you definitely need to tune your sound card and amplifier 28-Jan-20 04:29 PM the radioactive petrified wood i just ran is around 235cps...think it might just be an extra hot chunk of pitchblende 28-Jan-20 04:31 PM how big is your detector? 28-Jan-20 04:31 PM https://i.gyazo.com/cf26471e756a7a594e89e3cb51cb3978.png theres the pwood spectrum 28-Jan-20 04:31 PM getting over 10 000 counts from a low activity source is really unlikely with something that size, and your spectrum looks like it has a lot of noise 28-Jan-20 04:31 PM its the 38 B 57 so i think its a 38x57mm NaI 28-Jan-20 04:31 PM also, hint: switch to log 28-Jan-20 04:31 PM you need to tweak your lower level discriminator to not count random noise, but only pulses above a certain energy 28-Jan-20 04:31 PM for this size crystal I'd discard anything equivalent to below 10keV or so 28-Jan-20 04:31 PM you also need to re-train the thing every time you tweak it 28-Jan-20 04:33 PM also the pitchblende sets off the geiger tube i have (SBT10A) from across the room so its not exactly a low activity source, but not crazy hot either 28-Jan-20 04:34 PM still, 14khz count rate is nuts 28-Jan-20 04:34 PM either you have a really amazing detector or you're counting tons of noise 28-Jan-20 04:35 PM yeah definitely roll off your lows a bit there 28-Jan-20 04:35 PM if the leftmost side of the spectrum is the very highest point, that's a good sign you're getting a lot of noise 28-Jan-20 04:35 PM Let's see a background spectrum with linear vertical scale and log channel number? 28-Jan-20 04:36 PM what you should be seeing is a very low noise count, then a set distance, then a sharp x-ray peak 28-Jan-20 04:36 PM you'd need something like this to get a 14khz count rate 28-Jan-20 04:36 PM https://www.ebay.com/itm/Huge-130x65-NaI-Tl-Scintillation-gamma-spectrometer-Crystal-Detector-EMI-9758A/264389521674 28-Jan-20 04:36 PM actually not even that 28-Jan-20 04:36 PM https://www.ebay.com/itm/NaI-Tl-150-100mm-Scintillation-gamma-detector-Resolution-12-Built-in-preamp/223616087601 28-Jan-20 04:36 PM this guy can be trusted, and he says a 150x100 detector only gets 1.5khz 28-Jan-20 04:40 PM Did you build your own amplifier? 28-Jan-20 04:40 PM how far up should i bump the LLD setting? 28-Jan-20 04:40 PM no, i have a gs1100A i picked up on ebay 28-Jan-20 04:40 PM you should be looking at the waveform it shows you 28-Jan-20 04:40 PM when it stops looking like it's picking up random blips and once you have a few hundred cps maximum 28-Jan-20 04:44 PM You can also utilize the pulse shape monitor while you are changing your discriminator settings 28-Jan-20 05:05 PM Try increasing the sample width if increasing LLD doesn't help, and verify using the side-by-side monitor to see that invalid pulses are significantly different from valid pulses to ensure you are not dumping away low energy counts 28-Jan-20 05:14 PM things are starting to look a little better, will take another screencap in a few minutes after testing out these new settings 28-Jan-20 06:04 PM petrified wood: https://i.gyazo.com/56e2b7a21d33b1744e673e73bb031c26.png pitchblende: https://i.gyazo.com/b52e845b2138023d09c89e2390f35b76.png 28-Jan-20 06:04 PM blue on both is background 28-Jan-20 06:04 PM still getting crazy CPS numbers from the pitchblende 28-Jan-20 06:04 PM background is around 44cps, petrified wood 280, ...pitchblend 1500 28-Jan-20 06:06 PM that is a much much better spectrum 28-Jan-20 06:06 PM yeah i also realized i had the vertical axis in log mode...linear looks better 28-Jan-20 06:06 PM And a hot piece of pitchblende 28-Jan-20 06:06 PM I know it says in the software that the count rate is in cps, but is it at all possible it's actually reporting cpm? 28-Jan-20 06:06 PM Then these numbers will make a lot more sense 28-Jan-20 06:06 PM Put it into Theremino and compare? 28-Jan-20 06:11 PM numbers are basically identical, 43cps background (pulses per sec in Theremino) and 295cps from the petrified wood 28-Jan-20 06:11 PM put the pitchblende back in the other room already 28-Jan-20 06:11 PM will check in a couple mins 28-Jan-20 06:12 PM Well, have you got a dosimeter? 28-Jan-20 06:13 PM he's got one right there 28-Jan-20 06:13 PM with energy autocompensation and whatnot 28-Jan-20 06:13 PM Theremino is showing a bit over 1000cps from the pitchblende 28-Jan-20 06:13 PM but more rejected pulses 28-Jan-20 06:13 PM do not have a dosimeter and i would not trust the dose rate calcs off of my geiger counter either 28-Jan-20 06:13 PM if i was still shooting film i bet it would make a pretty quick autoradiograph 28-Jan-20 06:20 PM A well-calibrated survey meter and probe set is what I'm referring to. I'd trust one of those any day of the week over dose conversion obtained after a potentially unreliable spectrum lol 28-Jan-20 06:20 PM And of course the math is complicated (when you take detector variables and errors from counting statistics into account) 28-Jan-20 06:22 PM well my geiger counter is just one of the cheap kit ones + a soviet tube that is probably older than me...so it is far from calibrated besides having checked that it outputs the proper count number when feeding it a square wave 28-Jan-20 06:22 PM been meaning to pick up a better one but i have too many interests and projects to do that unless it is a great deal 28-Jan-20 06:31 PM https://www.ebay.com/itm/Keithley-Instruments-36150-36100-Radiation-Survey-Meter-Ion-Chamber-Geiger-/293348391361 28-Jan-20 06:31 PM Some fairly priced air ionization chamber survey meters 28-Jan-20 06:31 PM Should be quite good in holding dose rate calibration 28-Jan-20 06:31 PM Make a low ball offer, he's got 5 28-Jan-20 06:34 PM ive been holding out hope to pick up a cheap ludlum but have not been actively looking 28-Jan-20 06:34 PM might throw like a $20 offer to that guy and pick one up next time i am in phoenix if he accepts 28-Jan-20 06:34 PM Woah I didn't mean that low, but okay 28-Jan-20 06:35 PM with stuff where the seller obviously seems disinterested i have a shocking success rate with ridiculous offers 28-Jan-20 06:36 PM I should do that more often lol 28-Jan-20 06:36 PM There are still some thermofisher identifinder handheld isotope identification spectrometers up on eBay 28-Jan-20 06:37 PM https://www.ebay.com/itm/2-Lot-Vintage-1968-Harshaw-Integral-Line-NaI-Tl-Gamma-Scintillation-Detectors/264604250815 28-Jan-20 06:37 PM I should've made like a $400 offer when they were struggling to sell 28-Jan-20 06:37 PM from the sponsored items...kinda interesting 28-Jan-20 06:37 PM seller says mylar window but the paperwork obviously says Be 28-Jan-20 06:39 PM Yeah... Perhaps a very thin one too... 28-Jan-20 06:39 PM Might get that just for the window if the crystal turns out to be crap, the one on my proportional counter is just a bit too thick for low energy x-rays 28-Jan-20 06:40 PM have fun, dont blame me if they are DOA tho 28-Jan-20 06:40 PM https://www.ebay.com/itm/Exploranium-SAIC-GR-135-Isotope-Identifier-and-Dock-with-Cs137-Check-source/323937193614 28-Jan-20 06:40 PM from what i can tell that is what the Scionix 38B57 are out of 28-Jan-20 06:46 PM https://sci-hub.tw/10.1016/0168-9002(87)90900-4 28-Jan-20 06:46 PM Well, if the crystal is terribly yellowed, I might try this and just dissolve it away by simply washing them 28-Jan-20 06:46 PM Has anyone here actually tried this? 28-Jan-20 06:50 PM isnt thallium pretty nasty to dispose of? 28-Jan-20 06:50 PM not sure i would want to be dealing with that at home 28-Jan-20 06:51 PM There should only be a tiny amount of thallium in the doped crystal 28-Jan-20 06:51 PM ~200ppm in the paper, and the solvents are only touching the very surface 28-Jan-20 06:51 PM Yes it's still nasty though, and for sure chemical protection and proper disposal of waste will be required 28-Jan-20 06:51 PM I'll stick to isopropyl just to maximize the time I have to avoid dissolving most of the crystal away 28-Jan-20 06:51 PM If I decide that sandpaper will not work that is 28-Jan-20 07:06 PM NaI is ridiculously hygroscopic and will self-destruct in hours 28-Jan-20 07:06 PM the identifinder linked is nice, but I wouldn't buy it for $1000 28-Jan-20 07:07 PM So using alcohol solvents in a dry fume hood makes even more sense then 28-Jan-20 07:07 PM it's not the higher end models with the GM tubes and neutron scintillators 28-Jan-20 07:07 PM @Mason_Yu dry nitrogen is what I'd do yeah 28-Jan-20 07:08 PM https://www.flir.com/products/identifinder-r425/ 28-Jan-20 07:08 PM Want! 28-Jan-20 07:09 PM to be honest these would be pretty easy to make 28-Jan-20 07:09 PM it's somewhere in my plans to build the ultimate radiation-anything meter 28-Jan-20 07:09 PM with smart probes, internal reference 28-Jan-20 07:09 PM and then to have it actually calibrated 28-Jan-20 07:10 PM Includes a He-3 tube for neutrons? 28-Jan-20 07:11 PM the idea was external smart probes(eeprom for cal + voltage setting, etc), with an energy compensated GM tube inside, and a neutron tube next to it 28-Jan-20 07:11 PM or maybe not a neutron tube but a LiX scintillator 28-Jan-20 07:11 PM my biggest concern would be developing calibration procedures for all the hardware and ways to input them 28-Jan-20 07:11 PM since a basic cps/uSv/hr input would only work for non-proportional tubes 28-Jan-20 07:15 PM You planning on calibrating the gamma dose rates across multiple energies, not just Cs-137 right? 28-Jan-20 07:15 PM yeah I was thinking something like that 28-Jan-20 07:16 PM Need an x-ray machine! 28-Jan-20 07:16 PM But you've got that already haven't you 28-Jan-20 07:16 PM not yet 28-Jan-20 07:16 PM and depending on customs maybe never 28-Jan-20 07:16 PM but I was thinking - surely there are standard calibration procedures for cal houses and stuff? 28-Jan-20 07:16 PM I contacted our local standard authorities and they said "we'll have to look at it on an individual basis but generally it's not possible" 28-Jan-20 07:16 PM though this country has multiple private rad measurement product manufacturers with serious reputations, maybe I could contact them instead 28-Jan-20 07:18 PM https://www.nist.gov/system/files/documents/2017/02/07/procedure03v420.pdf 28-Jan-20 07:19 PM of course NIST would have a document for this 28-Jan-20 07:19 PM Certainly you don't have to go to this length for your stuff, but I think there are good lessons in here 28-Jan-20 07:19 PM It's pretty insane to be honest 28-Jan-20 07:19 PM see but to get an actual dose you need this 28-Jan-20 07:19 PM Yeah, but everyone just gets a NIST-traceable ionization chamber or something like that and call it a day 28-Jan-20 07:20 PM I suppose calibration is just done with a gigantic tunable x-ray source 28-Jan-20 07:20 PM Yeah with the standard detector approach I don't think you can ever quite capture the energy dependence of your detector 28-Jan-20 07:20 PM I guess it's best to start out the design with this in mind, and compensate for it by accounting for differences between front window dose, side wall dose and so on 28-Jan-20 07:20 PM So you get as flat of an energy response as possible 28-Jan-20 07:21 PM if I understand it correctly for scintillators you calibrate the energy response in percentages, and I think then you do something like one or two air kerma calibrations with known sources? 28-Jan-20 07:22 PM Yeah 28-Jan-20 07:22 PM since actual equivalent dose rate is related to energy, but with a scintillator you can do that on the fly 28-Jan-20 07:22 PM (this meter that I'll design will have a fast and high res always-on ADC) 28-Jan-20 07:35 PM do those little polimaster gamma/neutron scintillator pagers show up on ebay much these days? 28-Jan-20 07:35 PM they were always just a bit too expensive for me to consider 28-Jan-20 07:35 PM they do sometimes, but they're quite expensive 28-Jan-20 07:36 PM those are cute, seemed like a lot of untapped potential in the sensor package they were using though 28-Jan-20 07:36 PM where you could only really use it fully with a computer in the mix 28-Jan-20 08:03 PM my plan was to make a fully universal system by using a digitally adjustable analog section 28-Jan-20 08:03 PM digital comparators for non-proportional probes, variable gain amplifier + high resolution DAC for photomultiplier stuff 28-Jan-20 08:03 PM polimaster's stuff is cool but they're expensive from the factory too, so not many get to the second hand market 28-Jan-20 08:06 PM not sure what you could do for the neutron side of things but maybe this guy has single crystals he would sell? https://www.ebay.com/itm/CsI-36-16-5mm-scintillation-crystal-radiation-detector-lot-of-10/223568894169 28-Jan-20 08:06 PM I bought from Max before, he's sent me goodies as well 28-Jan-20 08:07 PM i am telling myself i do not need another project in the mix...especially one that is probably a bit out of my wheelhouse 28-Jan-20 08:07 PM I have a few crystals from him 28-Jan-20 08:07 PM but neutron-anything means you need either a He tube, or a LiX scintillator 28-Jan-20 08:07 PM and those are rare 28-Jan-20 08:07 PM SNM He3 tubes are pretty common and available though 28-Jan-20 08:07 PM not particularly cheap but they are proportional 28-Jan-20 08:14 PM i wish those were the same size as a Li based scintillator heh 28-Jan-20 08:17 PM heh yeah Li scints are tiny 28-Jan-20 08:17 PM I wonder, would water work as a scint for neutrons? 28-Jan-20 08:17 PM looks like it could, but needs fancy additives 28-Jan-20 08:20 PM i wonder what LND's prices are on their He3 tubes 28-Jan-20 08:20 PM they have some smaller ones than i remembered 28-Jan-20 08:20 PM probably very expensive 28-Jan-20 08:21 PM given LND's prices on not He3 tubes, I'd say high 28-Jan-20 08:21 PM oh, interesting 28-Jan-20 08:21 PM "Boron-coated straws" 28-Jan-20 08:21 PM https://www.sciencedirect.com/science/article/pii/S016890021001973X 28-Jan-20 08:21 PM needs B-10 enriched boron carbide though 28-Jan-20 08:22 PM isnt that basically what the B10 corona discharge tubes are? 28-Jan-20 08:24 PM it doesn't look like it 28-Jan-20 08:24 PM ah, it is sort of like it 28-Jan-20 08:24 PM it's basically an alpha detector GM tube but with a B4C coating on the inside 28-Jan-20 08:28 PM only reason i thought of it is that i have one of the B10 tubes 28-Jan-20 08:28 PM seemed familiar 28-Jan-20 08:31 PM should be manufacturable in a home lab 28-Jan-20 08:31 PM though I'm not sure how a uniform coating inside a thin tube is made 28-Jan-20 08:34 PM i do not think that the boron ones are proportional just in case you overlooked that (probably not) 28-Jan-20 08:34 PM they probably aren't yeah 28-Jan-20 08:34 PM since you're detecting alpha 28-Jan-20 08:34 PM you'd need a fun mixture of pure noble gases and equally pure and tiny amounts of bromine or chlorine 28-Jan-20 08:37 PM maybe you could buy some of the dented/crunched tubes as a B10 source if you wanted to DIY a tube 28-Jan-20 08:37 PM perhaps yeah 28-Jan-20 08:37 PM the gases are a pain though 28-Jan-20 08:43 PM https://arxiv.org/pdf/1209.0566.pdf 28-Jan-20 08:43 PM little bit better paper talks about sputtering the boron carbide 28-Jan-20 08:43 PM also says it can be operated at atmospheric pressure or lower? 28-Jan-20 08:43 PM that is cool 28-Jan-20 08:43 PM Argon/CO2 shouldnt be too hard though 28-Jan-20 08:52 PM Boron lined detectors often use P-10 fill gas, which is just 90% argon and 10% methane 28-Jan-20 08:52 PM Thanks to that they have quite fast timing responses 28-Jan-20 08:52 PM But I was told it's hard to discriminate against gamma when using it 28-Jan-20 08:55 PM P10 is a much easier fill 28-Jan-20 08:55 PM wouldn't p10 also be proportional-ish? 28-Jan-20 08:55 PM Yeah, they are proportional 28-Jan-20 08:55 PM alphas are high energy so maybe you could just discriminate anything that isn't high energy alphas 28-Jan-20 08:56 PM You'd get two separate plateau though, one for the alpha and the other for the lithium-7 28-Jan-20 08:56 PM alpha is the higher energy peak 28-Jan-20 08:56 PM are they close? 28-Jan-20 08:57 PM Well the alpha is like ~1.5 MeV? 28-Jan-20 08:57 PM 1.5 or 3 from what I'm reading 28-Jan-20 08:57 PM And the lithium 0.85 MeV 28-Jan-20 08:57 PM I think that can be discriminated out if you treated it as an analog probe 28-Jan-20 08:58 PM Yeah you'd set a crazy high threshold that also discriminate against gammas as well 28-Jan-20 08:58 PM The boron thickness is also on the order of microns 28-Jan-20 08:58 PM Due to short stopping distance of lithium and the alpha in solid boron 28-Jan-20 08:58 PM Could be hard to make at home 28-Jan-20 09:00 PM that's probably the hardest part then, if it's just p10 28-Jan-20 09:00 PM Not to mention the need for enrichment 28-Jan-20 09:00 PM 3M, of all companies, makes a whole line of b10 products 28-Jan-20 09:00 PM I'm assuming a pinch of 10b4c would last close to forever 29-Jan-20 06:10 AM Sorted through some stones I collected a few years ago 29-Jan-20 06:25 AM https://cdn.discordapp.com/attachments/408903047725711360/672084194754560021/IMG_20200129_151358.jpg 29-Jan-20 06:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6D647.png 29-Jan-20 06:38 AM Yay I found some U235 29-Jan-20 06:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-12B0A.png 29-Jan-20 09:59 AM <__ice9#6039> appreciates lead sheeting very nice aesthetic 29-Jan-20 10:00 AM thanks XD 29-Jan-20 10:40 AM 10x10mm is quite large https://www.aliexpress.com/item/32810522186.html 29-Jan-20 10:40 AM Am I confusing something else with PIN-photodiodes? 29-Jan-20 10:57 AM those are PN diodes, not PIN 29-Jan-20 10:57 AM => no fun to play with 29-Jan-20 12:00 PM a pattern emerges between all those rocks 29-Jan-20 12:00 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A501B.png 29-Jan-20 12:02 PM I can clearly see the pattern 29-Jan-20 12:02 PM it's HPGe! 29-Jan-20 12:02 PM Dang it he got me 29-Jan-20 12:03 PM you have adopted a fancy crystal, now it's your job to keep it cold and happy forever 29-Jan-20 12:03 PM I already reordered LN2 because I have only 15l left 29-Jan-20 12:04 PM keeping an inanimate germanium pet is a spendy hobby 29-Jan-20 12:04 PM need one of those long-hold dewars 29-Jan-20 12:07 PM need one of those proper detector dewars 29-Jan-20 12:07 PM not the tiny portable variant 29-Jan-20 12:08 PM DIY project: bolt a long hold dewar to hpge 29-Jan-20 12:08 PM sadly this is not pop top 29-Jan-20 12:08 PM you don't really think I will leave it at one single hpge, do you 29-Jan-20 12:08 PM can't you do something like extracting the cold finger 29-Jan-20 12:08 PM this is only a 20% 2 keV variant 29-Jan-20 12:08 PM Detector and dewar share the same vacuum, doing that without killin the crystal would be hard 29-Jan-20 12:08 PM to say the least 29-Jan-20 12:09 PM stuff the entire dewar into an oversized long hold dewar 29-Jan-20 12:10 PM I still want a >50% one, ideally N type 29-Jan-20 12:10 PM the kind that doesn't slowly expire when warm 29-Jan-20 12:10 PM every Ge does that 29-Jan-20 12:10 PM I thought you said one of the types doesn't 29-Jan-20 12:11 PM but seing stuff below 50 keV must be nice 29-Jan-20 12:11 PM they all do, some faster, some slower 29-Jan-20 12:11 PM Ge(Li) fast, HPGe slow 29-Jan-20 12:11 PM modern HPGes are done well enough to outlive their operator, even when warm 29-Jan-20 02:50 PM I went into the lab today and took a spectrum of a Cf-252 source moderated by poly with a boron lined tube 29-Jan-20 02:50 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3B0F4.png 29-Jan-20 02:50 PM You can see the two plateaus from the lithium and alpha particles 29-Jan-20 02:50 PM The long tail beyond the higher energy alpha plateau is due to the alternative reaction that produces a Li ion at ground state 6% of the time 29-Jan-20 02:50 PM And to properly discriminate against gammas, the threshold does need to be set quite high 29-Jan-20 02:54 PM See if you can take a cf-252 spectrum with a hard gamma source mixed in next time 29-Jan-20 02:55 PM Yeah that'll cause more problems 29-Jan-20 02:55 PM You can isolate a single peak within the plateau with some extrapolation I guess 29-Jan-20 02:58 PM For neutron detection as a built-in indicator that wouldn't really be necessary 29-Jan-20 02:59 PM Yeah I would not go for boron lined or BF3 tubes for any spectroscopy stuff (unless you are doing time of flight) 29-Jan-20 02:59 PM Hard if not impossible to unfold this spectrum, and only possible for high energy neutrons above 1 MeV 29-Jan-20 02:59 PM He3 is just much nicer 29-Jan-20 03:00 PM sadly there isn't any neutron selective scintillators that are affordable or manufacturable in DIY conditions 29-Jan-20 03:00 PM it's usually something like LiSi glass doped with Ce or something 29-Jan-20 03:00 PM with Li being in varying states of enrichment between Li6 and Li7 29-Jan-20 03:24 PM I think you can do pulse shape/height discrimination with regular plastic scintillators 29-Jan-20 03:24 PM Not very reliable and there are certainly nicer solutions like liquid scintillators, but prepare to empty your wallet I guess 29-Jan-20 03:27 PM plastic scintillators have basically no resolution 29-Jan-20 03:27 PM 20, 30, 50% 29-Jan-20 03:27 PM it all melts together into a large hunk of blips 29-Jan-20 03:28 PM Well with the Eljen liquid scintillators I was told you can actually see some reasonable MCA spectrum 29-Jan-20 03:28 PM but then again if there exist some magical plastics that totally ignore photons and only see neutrons, that'd be a good solution 29-Jan-20 03:28 PM I know a lot of plastics are simply used as suspension for the active ingredient 29-Jan-20 03:28 PM would be interesting to see if making your own plastic scints is possible 29-Jan-20 03:28 PM and if it is, to see whether certain dopants would work with neutrons selectively 29-Jan-20 03:33 PM https://arxiv.org/pdf/physics/9904004.pdf 29-Jan-20 03:33 PM Acquiring neutron selective dopants is likely going to be a difficult task 29-Jan-20 03:34 PM likely need to find a company with a proper sigma aldrich account 29-Jan-20 03:34 PM that company sells everything in the world if you have the money and the account 29-Jan-20 03:34 PM https://www.sigmaaldrich.com/catalog/product/aldrich/d210404?lang=en®ion=US 29-Jan-20 03:35 PM those are not lethal prices 29-Jan-20 03:35 PM And you don't need a lot 29-Jan-20 03:35 PM is it n-selective? 29-Jan-20 03:36 PM Not on their own, no 29-Jan-20 03:37 PM what kind of magic is required to make it n-selective? 29-Jan-20 03:37 PM https://www.researchgate.net/publication/315926120_Highly_Soluble_p-Terphenyl_and_Fluorene_Derivatives_as_Efficient_Dopants_in_Plastic_Scintillators_for_Sensitive_Nuclear_Material_Detection 29-Jan-20 03:38 PM poly(vinyltoluene) (PVT) matrices containing high loadings (>15.0 wt%) of 2,5-diphenyloxazole (PPO) offer neutron signal discrimination in gamma radiation background (termed pulse shape discrimination, PSD), however they suffer from poor mechanical properties 29-Jan-20 03:38 PM that's pretty standard 29-Jan-20 03:38 PM PVT is what a lot of saint gobain scints are 29-Jan-20 03:40 PM The synthesis process here is the headache 29-Jan-20 03:40 PM I don't have much experience with organic chemical synthesis but this looks intimidating 29-Jan-20 03:43 PM I'm not sure whether "matrices" refers to "bucket o polymer and mixer" here or "large chemical process with tons of steps to embed PPO into PVT" 29-Jan-20 03:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-AF7CE.png 29-Jan-20 03:51 PM It is technically a one step synthesis... 29-Jan-20 03:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-0E574.png 29-Jan-20 03:52 PM Very technically and only on paper 29-Jan-20 03:52 PM I'm more interested in how they did this in the old days 29-Jan-20 03:53 PM Was there even plastic scintillator back then? 29-Jan-20 03:54 PM Back at least to the 50s and 60s 29-Jan-20 03:54 PM https://libgen.is/book/index.php?md5=0296AAC8129A1F4A2B44D518DBB359B4 29-Jan-20 03:54 PM Here's a good old book 29-Jan-20 03:54 PM I guess it is just synthesis of a polymer, they did it the same way as other experimental polymers 29-Jan-20 03:57 PM wow that is, aside from the dopants, less complicated than i would expect 29-Jan-20 03:57 PM basically just a heat activated resin casting 29-Jan-20 03:58 PM hence why you see meter-tall hunks of scintillator on ebay for $400 29-Jan-20 03:58 PM and not meter-tall hunks of NaI:Tl monocrystal for $400 29-Jan-20 03:58 PM true 29-Jan-20 03:58 PM Well if you just mix PPO with polystyrene it really can't get simpler than that 29-Jan-20 03:58 PM I think that would be Bc408? 29-Jan-20 03:58 PM it would be really cool to be able to grow NaI(Tl) and other stuff at home though 29-Jan-20 03:59 PM ah no! 29-Jan-20 03:59 PM BC-412 and BC-416. 29-Jan-20 03:59 PM but that would be a more intensive project than laser rods even 29-Jan-20 03:59 PM they see fast neutrons 29-Jan-20 03:59 PM https://www.crystals.saint-gobain.com/sites/imdf.crystals.com/files/documents/bc400-404-408-412-416-data-sheet.pdf 29-Jan-20 03:59 PM it's good that they see fast neutrons, no need for moderation 29-Jan-20 04:11 PM https://sci-hub.tw/10.1063/1.1716850 29-Jan-20 04:11 PM Okay this is very interesting 29-Jan-20 04:11 PM This old paper is essentially saying that they mixed PPO with 1,3-Bis(trifluoromethyl)benzene and obtained a 23% FWHM neutron energy resolution at the 2.45 MeV DD fusion neutron energy 29-Jan-20 04:11 PM https://www.sigmaaldrich.com/catalog/product/aldrich/251186 29-Jan-20 04:11 PM Nowadays both chemicals are cheap 29-Jan-20 04:11 PM And apparently it works down to 0.25 MeV neutrons 29-Jan-20 04:14 PM That sounds good enough to do binary discrimination of "neutron" and "no neutron" 29-Jan-20 04:14 PM one issue for implementing it inside the device is getting affordable photomultipliers 29-Jan-20 04:14 PM SiPMs are great, but their price per surface area is quite high 29-Jan-20 04:14 PM ~$100-150 for 6x6mm 29-Jan-20 04:18 PM I'm not suggesting that this old dirt simple scintillator is going to match the performance of modern liquid ones. The interesting part is being able to do this on your own! Imagine mixing up a batch of neutron sensitive scintillators that can discriminate against gammas and get crude neutron spectra for all of $50 29-Jan-20 04:18 PM I'm talking new here of course, used pmts are everywhere but a gamble on what you get 29-Jan-20 04:18 PM thing is, you don't need to match the performance 29-Jan-20 04:18 PM if it's a cheap device that can see neutrons without having to scour ebay for parts, it's already great 29-Jan-20 04:18 PM He3 tubes are expensive too, if new, you know 29-Jan-20 04:19 PM Yeah, sometimes knowing there's neutrons is great, but spectral information is useful! 29-Jan-20 04:19 PM $900 per atm. liter for He3 29-Jan-20 04:19 PM And I'd argue this is actually comparable to He-3 performance 29-Jan-20 04:19 PM In certain ways 29-Jan-20 04:19 PM you could get an approximate spectrum from within the device without needing high end probes 29-Jan-20 04:19 PM but if you get a high end probe, you have that option too, externally 29-Jan-20 04:20 PM Yeah that certainly should be the approach to a radiation-everything meter 29-Jan-20 04:20 PM Okay I'm going to buy my first He3 tube 29-Jan-20 04:20 PM SNM-17 should be okay? 29-Jan-20 04:21 PM these discussions may include side effects such as: spontaneous ebay purchases, depletion of your bank account 29-Jan-20 04:22 PM lol 29-Jan-20 04:22 PM https://www.ebay.com/itm/High-Sensitivity-Helium-3-He-3-Neutron-Detector-Proportional-Counter-Tube-SNM-17/143504479344 29-Jan-20 04:23 PM there was a table of them 29-Jan-20 04:23 PM Are they any good? 29-Jan-20 04:24 PM well yeah they're also your only option 29-Jan-20 04:24 PM ah here 29-Jan-20 04:24 PM https://books.google.by/books?id=hTHRAAAAQBAJ&pg=PA3&lpg=PA3&dq=%D1%81%D0%BD%D0%BC-17+%D1%81%D0%BD%D0%BC-11&source=bl&ots=suoKiqP2bb&sig=ACfU3U0wVoMxHfHwS_j-NOpPxiAapcdJbA&hl=en&sa=X&ved=2ahUKEwjFlZW8h6rnAhVF6aYKHfHZCAUQ6AEwA3oECAoQAQ#v=onepage&q&f=false 29-Jan-20 04:24 PM page 45, use translate 29-Jan-20 04:24 PM some are proportional, some not 29-Jan-20 04:24 PM seems like a lot of them are boron coated 29-Jan-20 04:26 PM Uhh this book is not OCRed? 29-Jan-20 04:26 PM http://www.quartz1.com/price/techdata/Priemniki_i_detektory_izluchenij_2012.pdf 29-Jan-20 04:26 PM non-OCR version 29-Jan-20 04:26 PM Thanks 29-Jan-20 04:42 PM https://www.mouser.com/ProductDetail/ON-Semiconductor/MICROFC-60035-SMT-TR1?qs=sGAEpiMZZMtWNtIk7yMEsZQSjt2jgOZwzZs9KiM7XTQ5tfYP7fTxkg%3D%3D ...that is a bit better price than i think i have seen on a SiPM before 29-Jan-20 04:42 PM $73 for 6x6mm active area 29-Jan-20 04:43 PM that link doesn't seem to work for me 29-Jan-20 04:43 PM just goes to the mouser search page 29-Jan-20 04:44 PM I have a MicroFC-60035, it was around $110-150 a while ago 29-Jan-20 04:44 PM It's the only one worth buying at the moment 29-Jan-20 04:44 PM There's also KETEK(harder to obtain, untested by hobbyists afaik), and Hamamatsu(unobtainium unless you're a company, but good performance) 29-Jan-20 04:45 PM maybe they need the hash at the end of their links 29-Jan-20 04:46 PM Advansid is an option too 29-Jan-20 04:46 PM http://advansid.com/products/product-detail/asd-rgb-nuv-3s-p 29-Jan-20 04:46 PM yup that worked, ty 29-Jan-20 04:46 PM ~$14 for 1.2 mm diameter fast NUV SiPMs 29-Jan-20 04:46 PM For small stuff it's pretty nice 29-Jan-20 04:47 PM Tiny SiPMs are not worth it at all for detection though 29-Jan-20 04:47 PM even 6x6 is tiny 29-Jan-20 04:47 PM I use them for fibers and that's about as far as applications goes 29-Jan-20 04:47 PM Or make some sophisticated light guides 29-Jan-20 04:48 PM does advansid sell to people? 29-Jan-20 04:48 PM Don't know, used my .edu email 29-Jan-20 10:07 PM turned up the voltage a little bit on the PMT and things seemed to improve a bit...but i just do not think a Na(Tl) is sensitive enough to really do a proper gamma spectrum for Trinitite https://i.gyazo.com/aecabe12eb0f17e0c90ff90f3557739c.png 29-Jan-20 10:07 PM that actually looks alright 29-Jan-20 10:07 PM https://i.gyazo.com/f24497fab0a2225b0cd607aaf0e584b4.png 29-Jan-20 10:07 PM so you should see trinitite quite clearly 29-Jan-20 10:07 PM few others 29-Jan-20 10:07 PM yeah the trinitite measure is the black and a 1hr background measure is the blue line on that first one 29-Jan-20 10:17 PM i wonder if there is any difference between the pieces of trinitite i have...that is almost certainly beyond the abilities of my spectrometer i would imagine 29-Jan-20 10:17 PM i just stuck all ive got in front of it for that spectrum 29-Jan-20 10:18 PM I remember someone at my lab taking a spectrum of trinitite with NaI 29-Jan-20 10:18 PM one piece has a chunk of gravel in it... 29-Jan-20 10:18 PM was told it was probably part of the pad 29-Jan-20 10:18 PM It was a massive crystal though and had to stay in a lead castle for hours 29-Jan-20 10:18 PM Tiny sample I guess 29-Jan-20 10:19 PM yeah i have seen the hpge spectra from trinitite and its really pretty, nothing like what im getting 29-Jan-20 10:19 PM I don't know how good of a spectrum they got unfortunately 29-Jan-20 10:19 PM it hurt to have to buy it seeing how much is just laying on the ground out there 29-Jan-20 10:19 PM but they were keeping pretty close eyes on people and i didnt want any trouble on a military base 29-Jan-20 10:19 PM a bit hypocritical of them to prohibit people from taking any of it but then taking it anyway 29-Jan-20 10:20 PM Were you able to visit it? The two open days are always the busiest time of year for me 29-Jan-20 10:20 PM yeah i managed to go a couple years ago 29-Jan-20 10:20 PM not sure if it was worth it but it was really interesting...i wish they were a bit less strict 29-Jan-20 10:20 PM guy i was talking to who does research out there was telling me there are huge patches of trinitite out in the exclusion zone 29-Jan-20 10:20 PM whoever they paid to cover it up with a bulldozer in the 40s was a lazy guy and nobody wanted to check his work haha 29-Jan-20 10:20 PM also the prarie dogs are digging up big pieces 29-Jan-20 10:20 PM guess the only pieces they allow to be removed have to go back eventually too 29-Jan-20 10:20 PM there is a bucket of that stuff under the preservation shield 29-Jan-20 10:20 PM along with some stuff they "recovered" from the former owners of that rock shop 29-Jan-20 10:22 PM I wonder if one could fly to the Novaya Zemlya or Semipalatinsk polygons in Russia and pick up a bucket of trinitite 29-Jan-20 10:22 PM Man I'd like to go into the Nevada test site sometimes in the future (far future) 29-Jan-20 10:23 PM i should try to scan in some of the photos from this book i bought out there...has great photos of a literal pickup bed full of trinitite 29-Jan-20 10:23 PM Well, I wouldn't fly to Novaya Zemlya 29-Jan-20 10:23 PM given that you'd probably be immediately shot down by anti air 29-Jan-20 10:23 PM but visit 29-Jan-20 10:23 PM mason i wanted to do that until i read more 29-Jan-20 10:23 PM Security clearance man... 29-Jan-20 10:23 PM its a 6hr bus ride around the site 29-Jan-20 10:23 PM no electronics 29-Jan-20 10:23 PM no cameras 29-Jan-20 10:23 PM no leaving 29-Jan-20 10:23 PM no air conditioning 29-Jan-20 10:24 PM Yeah, but just seeing the landscape alone would be really impressive 29-Jan-20 10:24 PM you get to get out and take photos at sedan crater but other than that 90% youre stuck in the bus 29-Jan-20 10:24 PM i was really interested till i learned that... 29-Jan-20 10:24 PM And what I'm truly interested in are some of the earliest critical assemblies, not just the stuff they show to tourists 29-Jan-20 10:25 PM if you do ever go to Trinity get to the gate early! 29-Jan-20 10:25 PM i got there 2hrs early and was like 1/4mi back in line 29-Jan-20 10:25 PM by the time the gate opened it was over a mile of line 29-Jan-20 10:26 PM looks like Russia has their equivalent of trinitite 29-Jan-20 10:26 PM kharitony 29-Jan-20 10:26 PM black beads, but otherwise similar 29-Jan-20 10:27 PM i would totally go back if i could get some of the entomologists i know interested in studying the invertebrate fauna of ground zero...cracked me up seeing wolf spider burrows with turrets made out of trinitite 29-Jan-20 10:27 PM and the big harvester ant mounds full of little pieces of ejecta and trinitite 29-Jan-20 10:27 PM not sure how you would ever get permission to collect stuff from there in the first place 29-Jan-20 10:27 PM https://live.staticflickr.com/3948/33820339145_9420d264be_b.jpg 29-Jan-20 10:27 PM silly things 29-Jan-20 10:29 PM for Russia it's pretty easy 29-Jan-20 10:29 PM get a tour, tell the guide "can I have some samples" 29-Jan-20 10:29 PM yeah biggest issue would probably be getting it home 29-Jan-20 10:29 PM i saw a video of someone visiting and finding big chunks 29-Jan-20 10:29 PM Carl Willis i think 29-Jan-20 10:30 PM yeah, from what I can tell the black beads formed out of quartz settling around unfissioned Pu 29-Jan-20 10:30 PM Carl makes me jealous 29-Jan-20 10:30 PM which would be.. hot 29-Jan-20 10:30 PM I guess you could still get one or two through, but you'd want at least a small vial of them for spectroscopy 29-Jan-20 10:30 PM same with chernobyl, actually 29-Jan-20 10:32 PM also...if you go to trinity might not be a bad idea to bring a dust mask 29-Jan-20 10:32 PM you can easily find raw fuel and graphite fragments in the forests near it 29-Jan-20 10:32 PM but good luck getting it through 29-Jan-20 10:32 PM i was wishing i had one with the crazy wind that started up when i was there 29-Jan-20 10:32 PM ...oh well 29-Jan-20 10:32 PM and yeah the videos from the chernobyl area are nuts 29-Jan-20 10:33 PM what I don't see explored or shot on video is the siberian trails after the mayak explosion in russia in the fifties 29-Jan-20 10:33 PM i would love to see someone do a study on how much the ants there move around the hot stuff...or just radioactive material contaminated areas that have been remediated in general 29-Jan-20 10:33 PM a good swathe of siberia is still uninhabitable because of that pop 29-Jan-20 10:33 PM every time people check out ant hills at nuclear sites theyre screaming hot heh 29-Jan-20 10:34 PM I'm guessing the anthills are hot because the particle kills everything around it in a nice area, making safe sterile land for ants to build on 29-Jan-20 10:34 PM those are pretty damn hardy 29-Jan-20 10:34 PM also the siberian stuff would be really hard to get to without a helicopter 29-Jan-20 10:34 PM no actually i think they just dig up fragments 29-Jan-20 10:34 PM hm 29-Jan-20 10:35 PM my personal theory is it is sorta similar to how ants dig up garnets in some areas of the USA 29-Jan-20 10:35 PM they do not like the heavy pebbles in their nests 29-Jan-20 10:35 PM so they drag them out or something 29-Jan-20 10:35 PM https://www.facebook.com/photo.php?fbid=1296618117021611&set=a.1296617677021655.1073741909.100000203042561&type=3&theater 29-Jan-20 10:35 PM that and the next photo are about the ants at trinity 29-Jan-20 10:35 PM theyre digging up air cooled stuff that dropped down and was covered over by the rest of the debris 29-Jan-20 10:35 PM afaik 29-Jan-20 10:36 PM which the ants selectively filter out of the soil based on their size. 29-Jan-20 10:36 PM maybe that's the clue? 29-Jan-20 10:36 PM also, look, a bunch of nerds playing in the sand. 29-Jan-20 10:40 PM https://nmgs.nmt.edu/publications/guidebooks/downloads/61/61_p0221_p0229.pdf 29-Jan-20 10:40 PM talks about ants concentrating garnets and other minerals 29-Jan-20 10:40 PM i think it might be a similar thing to that just with radioactive stuff 29-Jan-20 10:40 PM Yeah I think it doesn't have anything to do with the activity 29-Jan-20 10:41 PM wasnt saying it did, just that in sites contaminated with radioactive stuff i would love to see a study done on how much ants move it around 29-Jan-20 10:41 PM seems like something that is easy to brush off until you are standing at the trinity site and there are dozens of big ant mounds 29-Jan-20 10:41 PM nests go down pretty deep too so i was wondering about remediated areas too 30-Jan-20 04:04 AM Sad life 30-Jan-20 04:04 AM one of the stones doesn't contain Uranium 30-Jan-20 04:04 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7CA40.png 30-Jan-20 04:04 AM you can see the missing lines 30-Jan-20 04:04 AM sadly the uranium lines are not swapped for some fission product lines 30-Jan-20 07:28 AM They get a might bit cranky with people collecting trinitite, and the rangers are watching, but you might get lucky with something stuck in the treads of your shoe. 30-Jan-20 07:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_2358-C94F0.JPG 30-Jan-20 07:28 AM Trying the same trick at NTS tends to cost you your boots. 30-Jan-20 08:14 AM that's just radioactive stones from a silver mine, no trinitite etc 30-Jan-20 08:14 AM 'tho a piece of that would be very interesting, maybe I can get my hands on some 30-Jan-20 08:14 AM ynow that I have measurement stuff good enough to see the low activita 30-Jan-20 09:17 AM it is pretty interesting stuff but i would only buy it if you are able to inspect the stuff in person first 30-Jan-20 09:17 AM there was some fake stuff on eBay a couple years back when i was checking for it 30-Jan-20 09:17 AM i should try to get photos of the pieces i have 30-Jan-20 02:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-596CD.png 30-Jan-20 02:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200130_225442-0B851.jpg 30-Jan-20 02:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D79AB.png 30-Jan-20 02:01 PM a cookie for the first person who can guess what my sample is 30-Jan-20 02:09 PM hmm.. Kr-85? a shiny new voltage regulator tube? :o 30-Jan-20 02:10 PM wow that was quick 30-Jan-20 02:10 PM way better, old german smoke detector 30-Jan-20 02:10 PM with way too much activity... 30-Jan-20 02:10 PM what gave it away? 30-Jan-20 02:10 PM or in other words: It looks like you've got a better gamma energy database than I do, with mine it would have taken me way longer 30-Jan-20 02:25 PM >.> i googled '514 keV' :D 30-Jan-20 02:25 PM cheated 30-Jan-20 02:26 PM dang you're good 30-Jan-20 02:26 PM XD 30-Jan-20 02:26 PM i suspected it may not have been that because i would've expected there to be a big hump of low-end beta noise activity, but on second glimpse you seem to be WAY zoomed in there 30-Jan-20 02:26 PM you and your ridiculous resolution 30-Jan-20 02:26 PM the bump at~350 keV is the compton edge, the bump at ~450 keV is... still to be determined 30-Jan-20 02:27 PM mx.qualia:>.> i googled '514 keV' :D mx.qualia:cheated Honestly having this much drive is all you need to get a decent job nowadays... 30-Jan-20 02:27 PM So many people won't even try to google things. 30-Jan-20 02:27 PM smh 30-Jan-20 02:27 PM Anyway its awesome you got that thing going @GigaSquirrel :) 30-Jan-20 02:28 PM i am in fact a googler by profession 30-Jan-20 02:28 PM something something sysadmin, doo dah, doo dah 30-Jan-20 02:28 PM heh... well I do a lot of scriptwork for my $dayjob and yea same 30-Jan-20 02:29 PM you can't believe how happy I am with it 30-Jan-20 02:29 PM next up will be @qualia with her Si(Li)s and another kind of elemental analysis 30-Jan-20 02:31 PM :D 30-Jan-20 02:31 PM (No stress I've had the HPGe for about a year before I got it going) 30-Jan-20 02:31 PM i might have to actually do something with that rhodium microfocus x-ray tube 30-Jan-20 02:32 PM ohh you got one? 30-Jan-20 02:32 PM yeah i've had it for like a year+ now 30-Jan-20 02:32 PM two, technically, one with a blown filament 30-Jan-20 02:32 PM so... one ^^ 30-Jan-20 02:32 PM it just needs a bunch of work to get going, literally just a bare tube 30-Jan-20 02:32 PM yeah :D 30-Jan-20 02:32 PM something something power supply something something oil immersion chassis something something shielding and interlocks 30-Jan-20 02:33 PM oh, this is going to be fun 30-Jan-20 02:33 PM yep... 30-Jan-20 02:35 PM in lieu of anything else, my thyratron filament transformer is isolated to 30kV 30-Jan-20 02:35 PM bit overspecced for a tiny tube, but it'll do 30-Jan-20 02:35 PM (still need to make a chassis for those thyratrons and run them through their paces.. too many projects) 30-Jan-20 02:37 PM ohhh, many, but exciting projects! 30-Jan-20 02:37 PM speaking of, that implosion shield... 30-Jan-20 02:37 PM getting the pinch going? 30-Jan-20 02:37 PM haha, i wish :D 30-Jan-20 02:37 PM no that's just me being a big fussy baby and not wanting to deal with shattering mason jars 30-Jan-20 02:37 PM although it will likely serve multiple purposes 30-Jan-20 02:37 PM the dense plasma focus project is probably on rather longer hold because i don't think i can safely do that in my, uh, dense suburban backyard 30-Jan-20 02:37 PM at least not without a lot of concrete 30-Jan-20 02:37 PM also macor is expensive and i'm lathe-stupid 30-Jan-20 02:41 PM fair enough 30-Jan-20 02:41 PM Yeah, macor is hella expensive :< 30-Jan-20 02:41 PM I would love to machine my own insulators 30-Jan-20 03:29 PM having a big scintillator on an always-running multichannel scaler is bad for the hypervigilance 30-Jan-20 03:29 PM there's a small background rise corresponding with about when i woke up.. i think 'cos the day before i'd ventilated my room out, and then sealed it up for the night.. then stirred up ambient accumulated radon upon waking up? maybe? 30-Jan-20 03:33 PM Easy way to check is to take a cotton pad, tape it to your vacuum cleaner and run it for about 30 minutes 30-Jan-20 03:33 PM The kind used for removing makeup, they're the best cheap absorber of radon 30-Jan-20 03:33 PM If you have a significant amount of radon, the pad will scare the living hell out of you with how hot it's going to be 30-Jan-20 03:33 PM Can be up over a mSv/hr for a few seconds after you turn it off 30-Jan-20 03:35 PM when it's warmer, i usually have a pair of box fans running, hanging from the ceiling -- they've got air filters ziptied to the back, and definitely get pretty angry after a while 30-Jan-20 03:35 PM so i know it definitely is present 30-Jan-20 03:35 PM yeah, you will get ramps in activity when you sleep then 30-Jan-20 03:36 PM (the air filter in our central air system will hit 5x-10x background after a couple hours :D) 30-Jan-20 03:36 PM that sounds a bit high 30-Jan-20 03:37 PM the first time i discovered that i hadn't realized how significant it was, and it was also in the middle of the CA wildfires so we'd had the filters running for days straight; i'd worried Some Kind Of Facility had gotten caught in the blaze, but managed to quell my panic before causing a ruckus about it 30-Jan-20 03:37 PM talk about bad timing 30-Jan-20 03:38 PM radon is a really huge contributor for late cancer 30-Jan-20 03:38 PM I think something like 40% 30-Jan-20 03:38 PM (citation needed) 30-Jan-20 03:38 PM yeh.. i'm not in a radon problem-area, but i have noticed that background radiation on this side of the bay area is markedly higher than on the other side of the bay 30-Jan-20 03:38 PM not sure why, nor have i fully qualified that 30-Jan-20 03:39 PM ask a local geology prof :P 30-Jan-20 03:44 PM @qualia if you were in roughly the LA area the wildfires at the end of 2018 did burn some of the contaminated area near Santa Susana...but that should not be a thing in the bay area 30-Jan-20 03:46 PM there's contaminated surface in the US? 30-Jan-20 03:46 PM https://thebulletin.org/2019/02/a-failure-of-governmental-candor-the-fire-at-the-contaminated-santa-susana-field-laboratory/ 30-Jan-20 03:46 PM theres a lot of contaminated surface in the USA 30-Jan-20 03:46 PM basically the entire trinity site...vast areas of the nevada national security site...few other reactor related incidents 30-Jan-20 03:46 PM oh also former weapons production facilities and the surrounding areas 30-Jan-20 03:46 PM friend of mine who lives near Oak Ridge has to take his deer in to get checked for radiation and has had a one seized before 30-Jan-20 03:49 PM interesting 30-Jan-20 03:50 PM http://knoxblogs.com/atomiccity/2008/11/27/checking_out_hot_deer_in_oak_r/ 30-Jan-20 03:50 PM guess its about 2% of the deer taken in the area 30-Jan-20 03:50 PM "Neil Giffen, the wildlife coordinator at Oak Ridge National Laboratory who works the check-out station for hunts, said the hottest deer ever taken was an 86-pound, 5 1/2-year-old doe killed in 1999 on Copper Ridge near the old Tower Shielding nuclear reactor site. The rad issue was strontium-90 in the bones. Normal radiation background would be something on the order of 30 to 40 counts per 2 minutes, and Giffen said that doe registered 853 counts. Authorities keep any deer with rad levels 1.5 times above background, he said. Nearly all of the hot deer are due to strontium-90 (a bone-seeking radionuclide). Giffen said only two deer have been restricted because of cesium-137 concentration in the muscle." 30-Jan-20 03:50 PM 1.5x background...yeah i would not want to eat that 30-Jan-20 03:50 PM ohhh also theres one place they did subcritical testing 30-Jan-20 03:57 PM subcritical? 30-Jan-20 03:57 PM isn't that just... exploding nuc materials over a bit of land and letting it sit there? 30-Jan-20 03:58 PM https://carlwillis.wordpress.com/2011/03/02/more-radioactive-goodies-from-bayo-canyon/ 30-Jan-20 03:58 PM pretty much, though i think they cleaned up most of it 30-Jan-20 03:58 PM I thought the "scorched earth" policy was more of a bad guy thing 30-Jan-20 03:58 PM though there's always the evil technique of putting some stable Sr, Co, and Cs next to the charge 30-Jan-20 03:58 PM salting 30-Jan-20 04:01 PM really it wouldnt have been such a big deal if they had purified the nuclear material they used a bit better... 30-Jan-20 04:01 PM think the basic premise for the Bayo Canyon stuff was fairly sound just badly executed 30-Jan-20 04:01 PM that's a pattern for the early nuclear experiments everywhere in the world 30-Jan-20 04:03 PM at least they didnt understand how terrible what they were doing was...wait 30-Jan-20 04:06 PM @LRM nah, further north than LA, but we certainly have our share of superfund sites and waste dumps up here 30-Jan-20 04:06 PM i got to visit (read: walk through some of) ames national lab a year or so ago and that was interesting.. big warnings at the entryway that nobody is allowed to move ceiling tiles or go into crawlspaces without health physicist signoff bc of beryllium and actinide contamination 30-Jan-20 04:06 PM can't tell if contamination control is just an extremely hard problem or if we just really sucked at it in our initial war-driven frenzy 30-Jan-20 04:09 PM a mix of both, but I suspect the real reason is that it was just disregarded 30-Jan-20 04:09 PM back then the goal was "make boom barrel YESTERDAY" rather than "make safe" 30-Jan-20 04:52 PM <__ice9#6039> LIGO is situated on part of the Hanford site, which has also been moderately contaminated 30-Jan-20 04:53 PM LIGO is just a toob though, don't think it pokes out anywhere at Hanford? 30-Jan-20 04:53 PM <__ice9#6039> Beryllium contamination is a genuinely difficult problem 30-Jan-20 04:53 PM <__ice9#6039> LIGO is above ground 30-Jan-20 04:53 PM doors/buildings I mean 30-Jan-20 04:53 PM where is the beryllium contamination worst? 30-Jan-20 04:54 PM hanford is a mess 30-Jan-20 04:54 PM <__ice9#6039> Hanford is radioactive contamination 30-Jan-20 04:54 PM they have tons of places where they literally do not know what is in the storage tunnels 30-Jan-20 04:54 PM just that it is bad 30-Jan-20 04:54 PM <__ice9#6039> My beryllium comment was a reply to a different point above 30-Jan-20 04:54 PM <__ice9#6039> Hanford has dozens of tanks of radioactive waste that have leaked into the groundwater 30-Jan-20 04:55 PM i wonder if anything is being done about the tunnels after the collapse a few years ago 30-Jan-20 04:56 PM <__ice9#6039> They chose the Hanford site to build this huge thing because it is such a large restricted area. 30-Jan-20 04:56 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580432143783-B0E18.png 30-Jan-20 04:56 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580432277235-3B70A.png 30-Jan-20 04:56 PM <__ice9#6039> It's difficult. 30-Jan-20 04:58 PM oh i guess after the collapse they did the favorite thing of the gov for contaminated structures...fill it with grout! 30-Jan-20 04:59 PM what in the world was beryllium doing in the WTC? o.O 30-Jan-20 04:59 PM makes grabbypaws at citation 29 30-Jan-20 04:59 PM all those microwave ovens 30-Jan-20 05:11 PM <__ice9#6039> Possible actually 30-Jan-20 05:11 PM <__ice9#6039> The oxide is actually a lot more hazardous than the metal-- more easily fragmented into powder 30-Jan-20 05:24 PM found a study where they tested the firefighters/first responders with, among other things, the BeLPT beryllium sensitization test, didn't find anything out of the ordinary 30-Jan-20 05:24 PM so could be 30-Jan-20 05:39 PM <__ice9#6039> ah yeah I remember seeing that in passing a while ago 30-Jan-20 05:40 PM wasn't there a huge contamination of asbestos? 30-Jan-20 05:40 PM <__ice9#6039> it's true that there have been detectable exposure incidents that did not appear to result in sensitization at the time 30-Jan-20 05:40 PM <__ice9#6039> Yes. 30-Jan-20 05:40 PM yeah I'd worry about that more 30-Jan-20 05:40 PM <__ice9#6039> but anyway it's all a dice game 30-Jan-20 05:40 PM <__ice9#6039> Yeah that reminds me of ceramic wool-- it's not known to cause mesothelioma, but it can still cause fibrotic conditions resembling silicosis. SuperWool has somewhat lower biopersistence, and just empirically in personal experience is not nearly as itchy when particles inevitably land on my socks. But it's a bit funny how similar the situation still is to actual asbestos. The nature of the use case is such that viable solutions tend to have this same issue to at least some degree. 30-Jan-20 06:10 PM BeO is absolutely everywhere in old and quite a bit of the newer RF gear 30-Jan-20 06:10 PM Essentially every cellphone basestation RF unit made before maybe 2010 has some BeO resistors in the output circulators/isolators and if maybe pre-2000, then also in the power transistors. 30-Jan-20 06:10 PM Usually the "Warning BerylliumOxide!" stickers are the one's that show you the best scrap the hoard :P 30-Jan-20 06:41 PM decided to check out google instead of trying to scan the photo in this book i have and: http://www.mine-engineer.com/mining/trinity.htm 30-Jan-20 06:41 PM great story about how basically everything in the commercial market escaped from the trinity site ...500lbs in the back of a pickup truck a load 30-Jan-20 11:02 PM Why is green stuff so hard to take photos of? I do not feel like fighting to get the color balance right in post processing but this is the trinitite from that gamma spectrum (and yes I spent entirely too much on this group of rocks): https://i.gyazo.com/d106da9a8863dcfed7e84b1df312dc6e.jpg 30-Jan-20 11:02 PM Color is not exactly right but close enough 31-Jan-20 10:53 AM trinitite is strangely extremely difficult to photograph, i spent a good half-hour with a friend's macro lens and my dslr and couldn't manage to get good color balance and detail capture on mine 31-Jan-20 10:53 AM probably needed more light 31-Jan-20 10:53 AM but yours looks good! 31-Jan-20 10:56 AM if anyone has a piece of confirmed trinitite they want a good spectrum of... 31-Jan-20 11:14 AM shipping trinitite out-of-country might be frowned upon tho 31-Jan-20 11:14 AM therefore, come visit :D 31-Jan-20 11:15 AM so I can smuggle it myself? XD 31-Jan-20 11:15 AM ... actually i'm not sure if traveling with an HPGe is more or less frowned upon 31-Jan-20 11:15 AM but sure, I will definitely visit you all one day 31-Jan-20 11:15 AM filled LN2, constantly smoking a bit 31-Jan-20 11:22 AM oh mood 31-Jan-20 11:22 AM done any hold time measurements yet? 31-Jan-20 11:22 AM also like.. i see cheap NIM LN2 level sensors on fleabay constantly but never see any sensors for 'em 31-Jan-20 11:22 AM wonder how hard it is to DIY one 31-Jan-20 11:22 AM think they're just a hollow tube & rod capacitor iirc 31-Jan-20 11:24 AM the dewar is in spec with ~2 days holding 31-Jan-20 11:24 AM but it's just the portable version, not made for any longer holding time 31-Jan-20 11:24 AM which kinda sucks tbh 31-Jan-20 11:24 AM and it's not easy at all to stick a level sensor in there, sadly 31-Jan-20 11:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-66AB8.png 31-Jan-20 11:34 AM aw, that is kinda awkward 31-Jan-20 11:35 AM yep 31-Jan-20 11:35 AM esp. refilling it every few days is kinds (very) annoying 31-Jan-20 11:35 AM wastes a lot of LN2 31-Jan-20 11:36 AM one of my SiLi dewars has a sticker on it from wherever it originally came from that reads 'Remember to fill with LN/2[sic] every monday and friday' 31-Jan-20 11:36 AM so i guess i've got that to look forward to 31-Jan-20 11:37 AM yay 31-Jan-20 11:37 AM maybe new pumping will improve that 31-Jan-20 11:37 AM I almost got a HPGe where I was told it needed refilling every week or so 31-Jan-20 11:37 AM according to the datasheet it would need it every ~2 months 31-Jan-20 11:37 AM so yeah 31-Jan-20 11:39 AM yeah i'm hoping 31-Jan-20 11:39 AM did you do anything special to protect the crystal during bakeout? 31-Jan-20 11:40 AM nope 31-Jan-20 11:40 AM II was just told to stay below 80°C 31-Jan-20 11:40 AM <__ice9#6039> Hmm I have a SiLi also, Princeton Gamma-Tech. Haven't had a chance to try operating it yet, though. 31-Jan-20 11:41 AM maybe a bit lower for SiLi, I suspect they might be a bit more temp sensitive 31-Jan-20 11:41 AM i got an awful txt version of a pdf of documentation for PGT HPGe/SiLis and it mentioned the availability of a 'Neutron Damage Repair Kit' for some of their instruments that consisted of all the hardware required to do your own high-vac high-temp crystal bakes to undo neutron-radiation-induced defects 31-Jan-20 11:41 AM was kinda interesting, i figured that'd be a death knell for these detectors 31-Jan-20 11:42 AM @__ice9 you're in germany, right? You can come over to test the thingy here if you want to 31-Jan-20 11:42 AM @qualia got a copy of that? ^^ 31-Jan-20 11:42 AM <__ice9#6039> Haha no Chicago 31-Jan-20 11:42 AM <__ice9#6039> Appreciate the offer though 31-Jan-20 11:42 AM ah, whoops, must have mixed something up there 31-Jan-20 11:42 AM eh, offer still stands XD 31-Jan-20 11:42 AM @__ice9 if you could grab a picture or five of the inside of the preamplifier box sometime i'd be super appreciative 31-Jan-20 11:43 AM <__ice9#6039> Appreciated likewise 31-Jan-20 11:43 AM don't need the bottom of the PCB, just the top lid could come off 31-Jan-20 11:43 AM <__ice9#6039> Huh yeah I could probably do that depending on the assembly method 31-Jan-20 11:44 AM should just be four screws on the sides of the little box with the BNC/SHV/DE-9 connectors 31-Jan-20 11:44 AM don't touch anything inside, there's high-ohm resistors that are probably fairly leakage-current sensitive 31-Jan-20 11:44 AM the FETs are probably pretty ESD-unforgiving also 31-Jan-20 11:45 AM eh, those resistors are just for biasing the detector, mostly filtering 31-Jan-20 11:46 AM but i'm curious because.. on the vacuum-side of my one SiLi detector, there are more wires connected to the vacuum electrical feedthrough than there are on the atmosphere side 31-Jan-20 11:46 AM one's not wired to anything 31-Jan-20 11:46 AM and there's a Mysterious Unconnected Pin Header on my preamp board 31-Jan-20 11:47 AM the preamp board isn't called 2001 or 2002 by any chance, is it? 31-Jan-20 11:47 AM Afaik SiLi is a lot less sensitive to temperatures 31-Jan-20 11:47 AM There exist off the shelf SiLi detectors driven by peltiers 31-Jan-20 11:48 AM the only number i could see on the board is, uh.. i think 153 31-Jan-20 11:48 AM maybe 152 31-Jan-20 11:48 AM would have to look 31-Jan-20 11:48 AM but that has got nothing to do with temperature sensitivity @Spirit 31-Jan-20 11:49 AM hm? 31-Jan-20 11:49 AM we're talking about heat death here, not operating temperature 31-Jan-20 11:49 AM oh, I see 31-Jan-20 11:49 AM https://twitter.com/profanegeometry/status/1223189482762993666 31-Jan-20 11:49 AM ooh discord previews all the images now :o 31-Jan-20 11:50 AM ah, that's not a preamp I've seen before 31-Jan-20 11:50 AM it does for desktop or web, not quite mobile app 31-Jan-20 11:50 AM neat though 31-Jan-20 11:51 AM ahh 31-Jan-20 11:51 AM also, looks up resistor color code 200 megaohms.. whatever :D 31-Jan-20 11:51 AM if grey meant something wacky like gigaohms then fingerprints and dust and all that would matter a lot more 31-Jan-20 11:53 AM but that's just an RC filter to keep out supply noise 31-Jan-20 11:53 AM the only cricital-ish resistor is inside the cryostat, in parallel to the integrating capacitor 31-Jan-20 11:56 AM ah, so it is 31-Jan-20 11:56 AM wasn't sure if it was a bias resistor or something 31-Jan-20 11:56 AM guess that makes sense considering those cap-standoffs go to ground 31-Jan-20 11:57 AM what voltage do these operate at? 31-Jan-20 11:59 AM one's -500V, the other -600V 31-Jan-20 12:00 PM <__ice9#6039> Also fwiw Si(Li) can and will run on a good Peltier stack, but LN2 is better 31-Jan-20 12:01 PM intriguing 31-Jan-20 12:01 PM every preamp frontend looks +/- like this 31-Jan-20 12:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B8180.png 31-Jan-20 12:01 PM the plate drawn at the fet gate is the integrating cap, that's drawn a bit weird 31-Jan-20 12:14 PM <__ice9#6039> Idk how useful this is tbh 31-Jan-20 12:14 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200131_1344262-8A05D.jpg 31-Jan-20 12:14 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200131_1407382-6D5A1.jpg 31-Jan-20 12:14 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200131_1407452-AEE0F.jpg 31-Jan-20 12:14 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200131_1407572-CA457.jpg 31-Jan-20 12:14 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200131_1408083-36349.jpg 31-Jan-20 12:14 PM <__ice9#6039> Removing the entire board is not really an option 31-Jan-20 12:15 PM yeah it's annoying 31-Jan-20 12:15 PM no worries there 31-Jan-20 12:15 PM what's the date code on those ICs? 31-Jan-20 12:16 PM <__ice9#6039> Mine seems to have more components than the one in the image shown, though-- likely a different layout 31-Jan-20 12:16 PM yours looks like the innards of the other SiLi i have -- we have almost the same model 31-Jan-20 12:16 PM <__ice9#6039> SP8842 DM74LS123N 31-Jan-20 12:16 PM you may, i think, have a larger-area detector than I 31-Jan-20 12:16 PM 88, ok 31-Jan-20 12:18 PM <__ice9#6039> Sadly, the window is punctured. I intend to use it effectively 'windowless' in vacuum. 31-Jan-20 12:18 PM same, on mine 31-Jan-20 12:18 PM if i figure out a clever trick for replacing it i'll let you know 31-Jan-20 12:18 PM 'cos i'd like to be able to use mine outside of atmosphere 31-Jan-20 12:20 PM <__ice9#6039> Polymer 0.4μm recommended as a lower-energy-resolving alternative to beryllium 8-25μm, usually over a nickel grid in either case 31-Jan-20 12:20 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200131_1419052-A83CB.jpg 31-Jan-20 12:20 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200131_1419212-9F07B.jpg 31-Jan-20 12:22 PM https://www.researchgate.net/publication/280972141_Design_and_poperties_of_low-energy_X-ray_transmission_windows_based_on_graphenic_carbon 31-Jan-20 12:22 PM this is a cool technique 31-Jan-20 12:22 PM <__ice9#6039> Hex grid visible, but damage is obvious. Figured just stick it in a chamber and find a way to get the x-rays in. 31-Jan-20 12:22 PM maybe possible to replicate at home to make windows 31-Jan-20 12:22 PM <__ice9#6039> Huh interesting 31-Jan-20 12:23 PM it's also interesting that they specifically mention the silicon crystal orientation 31-Jan-20 12:23 PM <__ice9#6039> I've had generally pretty good success rates in getting stuff from the literature to work, but I've never manipulated ultra thin films before-- may require a very steady hand 31-Jan-20 12:24 PM zero hand touching there as far as I can tell, aside from shoving things around 31-Jan-20 12:24 PM i wonder if you could sputter a new window right onto the screen 31-Jan-20 12:24 PM nope 31-Jan-20 12:24 PM back it with a microscope slide or something 31-Jan-20 12:24 PM needs to be vacuum perfect 31-Jan-20 12:24 PM not to mention being able to withstand an atmosphere of differential while being nanometers thin 31-Jan-20 12:24 PM there's also the polymer-on-silicon technique 31-Jan-20 12:24 PM oh, speaking of x-rays, I'll post a curiosity in #swap-meet 31-Jan-20 12:26 PM <__ice9#6039> Hmm this is way beyond my skill level or time availability 31-Jan-20 12:26 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200131-142555-27DC5.png 31-Jan-20 12:26 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200131-142606-B7AE6.png 31-Jan-20 12:27 PM graphenic carbon is hard, yeah 31-Jan-20 12:27 PM but what about polymer on silicon, or nitride on silicon? 31-Jan-20 12:27 PM though you can buy silicon nitride pretty easily, as TEM sample cells 31-Jan-20 12:27 PM <__ice9#6039> Not sure. Probably best to see how well the device works in vacuum first before contemplating potential restorations 31-Jan-20 12:28 PM https://www.emsdiasum.com/microscopy/products/grids/xray.aspx 31-Jan-20 12:28 PM such as this 31-Jan-20 12:28 PM I'm not sure if they will take atmospheric differential though 31-Jan-20 12:38 PM <__ice9#6039> Hmm idk I have some pretty thin XRF window Mylar meant for fluidics stuff that might work if it can be gently melted onto the existing window 31-Jan-20 12:38 PM <__ice9#6039> Probably purely passive heating from a heating element nearby, not a heat gun 31-Jan-20 12:38 PM <__ice9#6039> Would be tricky to ensure no leaks around the perimeter though 31-Jan-20 12:38 PM <__ice9#6039> Plus I'm not sure how to be pump the thing back down in the first place hmm 31-Jan-20 12:40 PM building a pumpdown adapter for these things is going to prove interesting 31-Jan-20 12:40 PM aren't they just pumped down as a whole in a vacuum chamber, then laser welded shut? 31-Jan-20 12:40 PM <__ice9#6039> I'd feel a bit better if I knew what that existing window was made of. It's too thin to tell. The coloration is dominated by thin film characteristics. No idea whether it's even metal or plastic. 31-Jan-20 12:40 PM its a soft brass set screw with eight holes drilled in it, on the underside of the part where the dewar mounts on 31-Jan-20 12:40 PM could be silicon nitride as well 31-Jan-20 12:41 PM i believe it needs to be unscrewed, pumped through those holes, then screwed back in to seal 31-Jan-20 12:41 PM not sure though 31-Jan-20 12:41 PM haven't been able to unstick mine and don't want to mar it up 31-Jan-20 12:41 PM <__ice9#6039> Interesting, rotary pass-through maybe 31-Jan-20 12:41 PM <__ice9#6039> Yeah understandable 31-Jan-20 12:41 PM oh we're talking about this one 31-Jan-20 12:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/fastsdd_6-C7100.png 31-Jan-20 12:41 PM well, I thought we were 31-Jan-20 12:41 PM <__ice9#6039> I have chambers large enough to fit the entire device minus the dewar easily 31-Jan-20 12:42 PM surprised two stages is sufficient 31-Jan-20 12:42 PM it's usually more than 2 31-Jan-20 12:42 PM but they only operate at around -20 to -50c 31-Jan-20 12:42 PM i have a two-stage peltier that manages around -40 to -50C yeah 31-Jan-20 12:42 PM <__ice9#6039> For Si(Li), if they are good quality Peltiers with proper surrounding insulation, yes that's good enough to at least make it work 31-Jan-20 12:42 PM <__ice9#6039> Yep 31-Jan-20 12:42 PM delta T seems to fall way off after that with more stages 31-Jan-20 12:43 PM the peltier sili I saw on ebay, but can't find again, was around -70C 31-Jan-20 12:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/0jswuXfguc5SCV4FTrIRWhgZMVMwDA1NvnKh-7A6z--7B8AD.png 31-Jan-20 12:43 PM but you can get a lot more extreme 31-Jan-20 12:43 PM <__ice9#6039> Using physically larger ones underneath is actually important 31-Jan-20 12:43 PM <__ice9#6039> Iirc dry ice temps are still not attainable without a lot of precooling though 31-Jan-20 12:43 PM <__ice9#6039> I have a chiller that I hacked to pump coolant at -18C 31-Jan-20 12:43 PM <__ice9#6039> It's not very powerful, though. 31-Jan-20 12:43 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200131-1447412-3A35B.png 31-Jan-20 12:43 PM <__ice9#6039> That seems to be about the practical limit, around -100C 31-Jan-20 12:43 PM <__ice9#6039> They just become much less effective at lower temperatures 31-Jan-20 01:00 PM <__ice9#6039> Ordered a few o-rings to fit the 37mm detector housing tube into a KF-40 flange adaptor 31-Jan-20 01:13 PM ok 31-Jan-20 01:13 PM so 31-Jan-20 01:13 PM hear me out 31-Jan-20 01:13 PM https://physics.nist.gov/PhysRefData/XrayMassCoef/ElemTab/z82.html 31-Jan-20 01:13 PM https://physics.nist.gov/PhysRefData/XrayMassCoef/ComTab/concrete.html 31-Jan-20 01:26 PM <__ice9#6039> Rather conspicuous difference toward the middle 31-Jan-20 01:26 PM <__ice9#6039> Idk my hottest sources currently live in a little castle of lead bricks 31-Jan-20 01:26 PM <__ice9#6039> Haven't cast a pig yet 31-Jan-20 01:26 PM <__ice9#6039> Tbh I really really do not like casting lead 31-Jan-20 01:27 PM I need a lead castle for my detector 31-Jan-20 01:27 PM <__ice9#6039> Hahaha 31-Jan-20 01:27 PM and man, lead is expensive 31-Jan-20 01:27 PM <__ice9#6039> For the volume needed, yes 31-Jan-20 01:27 PM this is why you need to be in the US 31-Jan-20 01:27 PM <__ice9#6039> If you go on eBay and 31-Jan-20 01:27 PM sneak into a gun range at night 31-Jan-20 01:27 PM ;) 31-Jan-20 01:27 PM <__ice9#6039> Yeah bullets 31-Jan-20 01:27 PM <__ice9#6039> Exactly 31-Jan-20 01:27 PM ...and get shot 31-Jan-20 01:27 PM (lead shot) 31-Jan-20 01:27 PM (off the ground) 31-Jan-20 01:27 PM <__ice9#6039> In the U.S. actually there are a lot of random people casting lead and selling it 31-Jan-20 01:28 PM a totally random occurrence, because guns are obviously nonexistent in the US 31-Jan-20 01:28 PM find a disused gun range... 31-Jan-20 01:28 PM <__ice9#6039> I genuinely have no idea why. Maybe it is one of those things like gold recovery where dumb people think it is somehow easy money and end up flooding the market 31-Jan-20 01:29 PM lot of it is prepper types who think they are going to need to make their own bullets...then some of the fishing hobby casting their own sinkers 31-Jan-20 01:29 PM sadly lead is very expensive here 31-Jan-20 01:29 PM up to several dollars per kilo 31-Jan-20 01:29 PM thats why people have trouble getting even $1/lb like they post it up for online here 31-Jan-20 01:30 PM it's like 2 to 3 € per kg here 31-Jan-20 01:30 PM same as here then 31-Jan-20 01:30 PM thats not terrible, a "good" price in the USA is around 50cents a pound for reclaimed lead 31-Jan-20 01:30 PM but that means you will have antimony and other stuff in the lead 31-Jan-20 01:30 PM <__ice9#6039> But yeah anyway 31-Jan-20 01:30 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Vapor-pressure-of-selected-metals-E3171.png 31-Jan-20 01:30 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Vapour-Pressure-Curves-for-Various-Materia-19A8A.gif 31-Jan-20 01:30 PM that doesn't matter 31-Jan-20 01:31 PM <__ice9#6039> These charts show how much brain damage you get from casting stuff out of lead if you don't use a supplied air respirator 31-Jan-20 01:31 PM ideally I can already get bricks from there 31-Jan-20 01:32 PM <__ice9#6039> The cadmium curve is a fun one too 31-Jan-20 01:32 PM cd is always quite fun 31-Jan-20 01:33 PM <__ice9#6039> Huge amounts of fumes at ordinary soldering temps. It's magical for soldering random dissimilar metals however. 31-Jan-20 01:34 PM which reminds me, I still have some Cd loaded silver solder here... 31-Jan-20 01:34 PM <__ice9#6039> Silver loading also helps a lot with unusual metals 31-Jan-20 01:35 PM I would hope any of these people are doing the lead casting stuff outdoors and making sure to minimize their exposure but then again I have seen people doing it in a closed garage online before 31-Jan-20 01:35 PM those people seem extra masochistic...seems like you would get enough fumes from that to feel very sick 31-Jan-20 01:35 PM my workshop has a wooden floor, so casting inside is out of the question anyways 31-Jan-20 01:36 PM <__ice9#6039> Using my somewhat frightening Superior No. 71 HF flux, I have soldered stainless steel to copper, stainless to stainless, copper to Kanthal-A1, etc 31-Jan-20 01:36 PM <__ice9#6039> But only with silver solder. Normal lead-free SnCu0.7 doesn't work as well 31-Jan-20 01:36 PM <__ice9#6039> But with Cd based solder I have been able to solder aluminum to pretty much anything 31-Jan-20 01:36 PM <__ice9#6039> Given a bit of patience and a respirator 31-Jan-20 01:39 PM if only there was a reliable way of soldering glass to metal :P 31-Jan-20 01:40 PM <__ice9#6039> Silver chloride, 457C 31-Jan-20 01:40 PM <__ice9#6039> Or gallium lol 31-Jan-20 01:42 PM I just want to cheat at making glass seals 31-Jan-20 01:46 PM do the glass to tungsten oxide seals work at larger scales than just wire? 31-Jan-20 01:48 PM aren't the large seals(e.g. in x-ray tubes) made using those snakey shapes? 31-Jan-20 01:48 PM might have to bug Charles again for an explanation of the voodoo 31-Jan-20 01:48 PM as far as I know it's just the CTE of the glass versus metal being sliiiiiightly mismatched 31-Jan-20 02:00 PM <__ice9#6039> The tungsten oxide ones need to have a relatively smooth surface on the tungsten, no parallel grooves for instance (common) 31-Jan-20 02:39 PM That cadmium curve reminds me of a funny video I saw more than a decade ago 31-Jan-20 02:39 PM It was of a cadmium based smoke mix. Such evil looking dense yellow smoke. 31-Jan-20 02:39 PM Best part is that I'm pretty sure it was in some dudes backyard. 01-Feb-20 02:26 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200201_110602-4D702.jpg 01-Feb-20 02:26 AM you dense motherf... 01-Feb-20 06:30 AM ok 01-Feb-20 06:30 AM well 01-Feb-20 06:30 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-FF261.png 01-Feb-20 06:30 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7A187.png 01-Feb-20 06:30 AM gray is out in the open, red is with lead 01-Feb-20 07:07 AM What a nice difference 01-Feb-20 09:05 AM i wish HPGe stuff was a bit more accessible 01-Feb-20 09:05 AM thats a pretty crazy drop off with that lead 01-Feb-20 09:27 AM just ask your local lab that could have one 01-Feb-20 09:27 AM I've seen sooo many left in storage 'cause they were no longer needed 01-Feb-20 09:29 AM UCI (most local large university) is pretty stingy about their gear...and i don't know anyone who goes there anymore. 01-Feb-20 09:29 AM would not even know who to bug about that sort of thing 01-Feb-20 09:29 AM also...does anyone know for sure if the CHM-11 is He3 or B10? the listing for them on eBay someone linked the other day says He3 but a couple other places say B10 01-Feb-20 09:32 AM it's B10, wall coated 01-Feb-20 09:34 AM and the SNM-17 is the He3 one and not B10 01-Feb-20 09:35 AM yep 01-Feb-20 09:35 AM https://consensus-group.ru/radiation-counters/neutron-counters All on this list are He3 for sure 01-Feb-20 09:43 AM i do not know if that is really accurate...isn't the SI19N a B10 tube? 01-Feb-20 09:45 AM nope 01-Feb-20 09:47 AM almost everything i have seen, including when i bought mine, talks about those as B10 tubes 01-Feb-20 09:47 AM I am so confused 01-Feb-20 09:53 AM lol? 01-Feb-20 09:53 AM if it is He3 i got a crazy deal on it 01-Feb-20 09:53 AM I only know of one place where they're described as B10, that's diyphysics (or sth similar?) 01-Feb-20 09:53 AM and well they're not exactly known to check their stuff well 01-Feb-20 09:54 AM few places on the fusor forum too and youtube (might be the same people) 01-Feb-20 09:54 AM well 01-Feb-20 09:54 AM the same fusor forum where people think it's a good idea to bandsaw beryllium? 01-Feb-20 09:55 AM guess so heh 01-Feb-20 09:55 AM but also the russian guy i bought it from 01-Feb-20 09:55 AM when the other stuff lined up with that I guess I was lead astray 01-Feb-20 10:06 AM well then, congrats on the He3 01-Feb-20 10:56 AM lol 01-Feb-20 10:56 AM now I want also some fancy detectors 01-Feb-20 11:12 AM can recommend 01-Feb-20 11:15 AM @GigaSquirrel was thinking more about "just ask your local lab that could have one"...can you recommend any types in particular? lol. just email the university physics department? 01-Feb-20 11:16 AM go with HPGe, not Ge(Li) 01-Feb-20 11:16 AM if you have a lathe offer to take broken ones with bad dewars and just repump them 01-Feb-20 11:16 AM but all in all, take what you can get 01-Feb-20 11:16 AM n type has better resolution at lower energies than p type and if they tell you a percentage it's relative efficiency, basically just a weird way to classify size 01-Feb-20 11:23 AM i think UCI has a vastly better equipped shop than i do so i sorta think any that needed fixing probably already were fixed but maybe not 01-Feb-20 12:03 PM hmmm 01-Feb-20 12:03 PM yeah where to ask for broken HPGe? PTB? 01-Feb-20 12:05 PM lfu bayern almost gave me one, the issue was somewhere else, not in them not wanting to give me one 01-Feb-20 12:05 PM GSI as well 01-Feb-20 12:05 PM I could fix them with your tips 01-Feb-20 12:05 PM always happy to help, I got plenty of help with mine as well ^^ 01-Feb-20 12:09 PM do they surface in the ebay sometimes? 01-Feb-20 12:09 PM In my experience at-least anything surfaces on eBay at-least once heh... If its Legal to it'll surface more than once, if its illegal... probably only once or twice heh.. 01-Feb-20 12:11 PM there are some on ebay right now re: HPGe i think... 01-Feb-20 12:11 PM there is one in texas that i kinda want to throw a ridiculously low offer at but it is too far and too much of an imposition on anyone i know there 01-Feb-20 12:11 PM already at a good price of $725 01-Feb-20 12:11 PM might be going to a wedding in texas later this year though...or i would link it 01-Feb-20 12:13 PM yeah there are some on ebay, but I'm not sure I would spend that amount without any prior testing 01-Feb-20 12:13 PM @LRM many on ebay are Ge(Li) 01-Feb-20 12:13 PM (read: dead) 01-Feb-20 12:13 PM if the cap looks like this it's geli for sure 01-Feb-20 12:13 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200201_211431-1DDCE.jpg 01-Feb-20 12:16 PM want me to PM you the link to you so you can double check the info yourself? probably a moot point anyway and it will sell before i am anywhere near texas and thinking of making an offer anyway 01-Feb-20 12:16 PM sounds good to me 01-Feb-20 12:21 PM is there anything that the Ge(Li) stuff can be used for once it experiences heat death? 01-Feb-20 12:21 PM probably not but it would be interesting for them to find new life 01-Feb-20 12:22 PM I'm using mine as decoration 01-Feb-20 12:22 PM also it's some 100g of Ge, so that's actually worth quite a lot 01-Feb-20 12:22 PM So what, sell the Ge, buy HPGe? 01-Feb-20 12:23 PM that decision is up to you 01-Feb-20 01:15 PM 100g of Ge is not worth that much 01-Feb-20 01:15 PM maybe around $100-150 in scrap 01-Feb-20 01:15 PM if you can find a buyer 01-Feb-20 01:27 PM 100s 01-Feb-20 01:27 PM mine is 800g 01-Feb-20 01:27 PM and if 800€ aren't much for you I want your salary 01-Feb-20 01:28 PM show me a place that buys scrap dead doped Ge for 1 eur/gram 01-Feb-20 01:28 PM dunno, you were talking about 1-1.5 per g 01-Feb-20 01:29 PM that's the scrap price, but nnnnobody will buy it for that sadly 01-Feb-20 05:12 PM <__ice9#6039> Idk I got my Si(Li) for $70 01-Feb-20 05:12 PM <__ice9#6039> Window is damaged so I want to mount it in a vacuum chamber, but for the price that's acceptable to me 02-Feb-20 02:46 AM those labjacks are surprisingly robust 02-Feb-20 02:46 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-30945.png 02-Feb-20 06:48 AM @__ice9 Does SI(Li) die at room temp? Does it work for you now? 02-Feb-20 06:49 AM it doesn't die at room temp, afaik Ge(Li) is the only detector that does 02-Feb-20 07:37 AM <__ice9#6039> Correct it is fine 02-Feb-20 07:37 AM <__ice9#6039> I'm apprehensive to attempt to power it in air, though, and I am out of LN2 ATM anyway 02-Feb-20 07:37 AM <__ice9#6039> I ordered some o-rings to make the entire snout of it fit a KF40 flange though 02-Feb-20 07:37 AM <__ice9#6039> So with a bit of grease I should be able to pull a good vacuum around it, making up for the broken window 02-Feb-20 07:37 AM <__ice9#6039> Getting XRF suitable x-rays into a chamber isn't too difficult either 02-Feb-20 07:37 AM <__ice9#6039> I want it for pretty much just XRF purposes 02-Feb-20 07:37 AM <__ice9#6039> As a higher precision alternative to my existing NaI(Tl) PMTs 02-Feb-20 07:37 AM <__ice9#6039> Also yeah those lab jacks are pretty tough 02-Feb-20 10:18 AM @GigaSquirrel That pile makes me uneasy. Just waiting to crush some toes. 02-Feb-20 10:22 AM toes? that looks like it might crush some flooring! 02-Feb-20 10:22 AM how much is each of those blocks? 10kg? 02-Feb-20 10:22 AM probably double that 02-Feb-20 10:32 AM 60 kg in total 02-Feb-20 10:56 AM <__ice9#6039> Just curious-- what is the simplest approach for an ion source for deuterium? Figure a couple hundred kV accelerating voltage and a few mA beam current. How difficult would it be to create one? Are there plans for any kind of validated design already? I see plenty of papers, but they always leave out crucial details, they are often designed for vastly larger systems, and it is obvious that the electrode voltages must be carefully tuned for the device geometry to avoid losing much of the beam by impinging on the walls. 02-Feb-20 10:57 AM old x-ray transformers 02-Feb-20 10:57 AM <__ice9#6039> I know that. Assume I already have a PSU. 02-Feb-20 10:57 AM <__ice9#6039> I mean the device itself 02-Feb-20 10:57 AM regular ion sources should work for deuterium 02-Feb-20 10:59 AM <__ice9#6039> Where does one buy a "regular ion source"? I have had trouble finding much about this. There are many different kinds. Not sure how many are meant for hundreds of kV vs only a few kV. 02-Feb-20 10:59 AM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580669980471-94455.png 02-Feb-20 11:00 AM by that I mean regular ion source construction 02-Feb-20 11:00 AM <__ice9#6039> Also the papers I have seen seem like they usually have some kind of cavity with einzal lenses a bit ahead of the source 02-Feb-20 11:00 AM <__ice9#6039> Whereas these all look like open sources 02-Feb-20 11:00 AM <__ice9#6039> Hmm ok, but.. how does one know how to construct one in the proper form to avoid beam impingement or arcing? Where would one begin? 02-Feb-20 11:00 AM <__ice9#6039> Is it better to think of it as separating out the source itself from the initial electrostatic acceleration? 02-Feb-20 11:02 AM perhaps @Applied_Ion would know 02-Feb-20 11:02 AM <__ice9#6039> How does one ensure that the electrons are properly separated out instead of just making the equivalent of a big deuterium lamp? 02-Feb-20 11:02 AM <__ice9#6039> Hmm I see 02-Feb-20 11:10 AM <__ice9#6039> Typical example 02-Feb-20 11:10 AM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1-s2.0-S0920379619306362-gr1-46287.jpg 02-Feb-20 11:10 AM <__ice9#6039> There just always seems to be missing information. I do see some sources listed for sale, but not with the initial accelerator component. 02-Feb-20 11:10 AM <__ice9#6039> So it becomes rather complicated rather quickly 02-Feb-20 11:36 AM @__ice9 A few hundred kV at a few mA is quite a lot of power. Do you know the Amateur Scientist deuterium accellerator? Source is about 10uA and is a capilary in a glass sleeve. For 1ma I think you need a penning ion source design. Electrons aren't a problem AFAIK, they fall away from your extraction electrodes. Getting a high quality atomic, rather than molecular beam is more of an effort. Fusor.net forums have some designs but I don't know how well they work. 02-Feb-20 11:47 AM @ @__ice9 getting a few hundred kV at mA of current is a huge undertaking. You can get uA without a terrible amount of trouble, but mA is a different ballgame. Of course you could buy Glassman supplies that do this, but it's definitely not cheap at that level. That's on the order of bias we use for our electron linac gun lol. When you ionize the source, electrons aren't the issue due to the potential you apply to extract the ions. For that high current, you are looking at either high power rf ionization or a duoplasmatron configuration. Probably even bigger of a challenge is actually feeding in 100+ kV to high vacuum without breakdown. At mA current levels, this becomes even more difficult. Lots of Corona losses too if you are not careful, this is like a hardcore engineering effort lol. Fusor.net ion sources are pretty much just toys, simple capillary ion sources, like one anode layer ion source. All very low voltage or current, nowhere near the level you are looking at 02-Feb-20 11:47 AM This is an electron gun injector rated to maybe -125kV. This is an old design never used at our lab I obtained before it was tossed. We feed in up to a few mA of bias current on the gun, then have a supply that pulses up to 12A (grounded grid triode configuration.) Coaxial design rated to 50 ohms for fast pulses. Not trivial designing large high voltage, high current guns lol. This will be converted to the injector for my accelerator EXEDA at several hundred kV, 1kA pulsed, which is another thing in itself. But just to show the scale of what you would expect at the levels you are looking at. Ion sources would be even larger than this at this level, factoring in gas and ionization. 02-Feb-20 11:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Linac_Injector_-_Size_Reference-6ACC8.jpg 02-Feb-20 11:47 AM @__ice9 none of the stuff you will find on ebay will be rated for even close to 100kV, mA level ion source operation lol. Thats like big physics facility level custom guns. You could design and build your own, depending on what you are trying to achieve, but it won't be a small endeavor 02-Feb-20 11:47 AM Now, one of my goals for EXEDA is driving a unique type of ion accelerator capable of several MeV of pulsed current at the amp level, but probably not what you are after lol 02-Feb-20 12:15 PM Also note that the extracted beam current is not the same as the injected current. If you are looking to use it for high vacuum applications, you will also need a serious differential pumping setup. You have to design the gun to be able to extract the beam current you need. 02-Feb-20 12:15 PM Like in my case, I need to inject about 30kA pulsed into the diode load to extract maybe a few kA of actual beam current 02-Feb-20 12:15 PM For the accelerator gun at the lab, we inject about 20A in pulsed to get maybe 12A out 02-Feb-20 12:33 PM Speaking of ion sources, does anyone here had any feedback or on-hands experience with that 299$ anode layer ion source from eBay? few kV and low current is all I need for experiments. How does it look regarding plasma purity (contamination by metal of the ion source)? 02-Feb-20 12:45 PM <__ice9#6039> Hmm I see. I had (perhaps incorrectly?) assumed that the ion current would be of a comparable power level or within a small multiple of the power level for electrical current. 02-Feb-20 12:45 PM <__ice9#6039> 100kV at 1mA is only 100W. I expected power draw within several multiples of that and a cavity at the beginning of perhaps several cm diameter. This may just be incorrect, not sure. 02-Feb-20 12:45 PM <__ice9#6039> Please note, though, that I am not asking about the power supply. I have become fairly decent at making large high voltage power supplies cheaply. 02-Feb-20 12:45 PM <__ice9#6039> I was strictly asking about the physical device and electrode voltages, filament/etc temperatures, gas pressure levels, etc 02-Feb-20 12:45 PM <__ice9#6039> I have designed devices at comparable voltage without any visible corona. 02-Feb-20 12:45 PM <__ice9#6039> Also, this is not about pulses-- just continuous mode operation 02-Feb-20 01:03 PM <__ice9#6039> @Applied_Ion Anyway-- could you tell me more about the actual device? I really do not have any major difficulties producing up to several kW at up to 200kV electrical power. It would become difficult at like the 10kW level or so, but I have done that once at 10kV and could design a similar device at 100 if needed. I know about the PSU and feed-through considerations, I have suitable vacuum equipment, etc. 02-Feb-20 01:03 PM <__ice9#6039> I just do not actually know what shape and dimensions are needed for the physical components in the source and basic accelerator to avoid e.g. failing to produce a beam at all, or just hitting the walls, etc. It seems like a huge amount of modeling work is needed for this and the designs are not shared in enough detail to replicate. 02-Feb-20 01:08 PM Which device specifically (I mentioned a lot lol)? If power is not an issue, that's only one side of the equation. The other is the feedthrough and interface. There is no set dimensions or shape really, it is highly dependent on the system specifications. Sources like this are always custom to the application, no one universal blueprint. A lot more specs than just voltage and current, including parameters such as spot size, emittance, etc. Unfortunately, if you want to know about the beam dynamics, modeling is the only way to go, it's impossible to know exactly how the beam will behave without modeling. 02-Feb-20 01:08 PM <__ice9#6039> For context, yes it's for fusion. It's possible that less accelerating voltage might be needed, which could allow more beam current. 02-Feb-20 01:08 PM <__ice9#6039> The ion source and the initial accelerator 02-Feb-20 01:08 PM <__ice9#6039> Basically just this except with dimensions and materials etc listed. 02-Feb-20 01:08 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1-s2.0-S0920379619306362-gr1-BBA28.jpg 02-Feb-20 01:09 PM @__ice9 Have you read the phillips accelerators document? 02-Feb-20 01:09 PM <__ice9#6039> Not yet, reference appreciated and locating now 02-Feb-20 01:09 PM <__ice9#6039> Having trouble finding that quickly. More detail? 02-Feb-20 01:09 PM <__ice9#6039> Am not worried about the feed-through. A wide enough flange full of enough epoxy will survive any voltage. 02-Feb-20 01:09 PM <__ice9#6039> @ali_as more detail on that document? 02-Feb-20 01:13 PM Yeah that's a huge system lol. Multiple stages of differential pumping, lots of optics. Definitely need to model that for sure with something like SIMION. On the insulator, that is true, but you have to factor outgassing and permeation of the epoxy, going to add a lot to your gas load, especially as it gets bigger. Also definitely have to worry about triple point junctions between various media (air, insulator, metal, vacuum, etc) 02-Feb-20 01:13 PM <__ice9#6039> Specifically a centrally bored plastic cylinder with a copper rod down the middle potted into a flange in epoxy is simple and effective. An inner coating and bakeout controls outgassing simply enough. 02-Feb-20 01:13 PM <__ice9#6039> I'm also pretty decent with ceramics at this point if it comes to that, fwiw 02-Feb-20 01:15 PM @__ice9 My description was not great, this is the document. https://web.archive.org/web/20050526040715/http://freespace.virgin.net/muko.muko/ch8.pdf 02-Feb-20 01:15 PM <__ice9#6039> Thanks! 02-Feb-20 01:15 PM Fortunately, the gun is fairly simple. They don't need to be complex. Cathode is just a hot cathode to ionize the gas, shape probably isn't super critical in this case. Large tungsten filament or strip. Anode is just plate with bore in it, though they use an interesting floating electrode configuration which isn't as common like that 02-Feb-20 01:15 PM Honestly if you ionize the gas and have an extraction voltage, you will get beam. However, it would need optics for steering and control, and it would be good to know the overall effect of the anode shape on the beam divergence 02-Feb-20 01:17 PM <__ice9#6039> Ok, that's consistent with my impressions from the literature 02-Feb-20 01:17 PM <__ice9#6039> Huh 02-Feb-20 01:17 PM <__ice9#6039> Really? 02-Feb-20 01:17 PM <__ice9#6039> Surely there are more details than that to prevent just getting a giant deuterium lamp 02-Feb-20 01:17 PM No, that's all an ion gun is essentially lol 02-Feb-20 01:17 PM <__ice9#6039> Arcing would be suppressed at a low enough pressure level though 02-Feb-20 01:17 PM You ionize gas 02-Feb-20 01:17 PM You extract the ions 02-Feb-20 01:18 PM <__ice9#6039> Don't you need magnets to separate out the electrons? 02-Feb-20 01:18 PM <__ice9#6039> Yeah exactly 02-Feb-20 01:18 PM No 02-Feb-20 01:18 PM <__ice9#6039> Hmm ok, some designs I have seen used them 02-Feb-20 01:18 PM <__ice9#6039> How does the extractor work? Purely electrostatic? 02-Feb-20 01:18 PM Not to separate. But the design has problems without a penning cell. Huge current and wasted. 02-Feb-20 01:19 PM This is an odd setup though 02-Feb-20 01:19 PM It doesn't just look like beam 02-Feb-20 01:19 PM No wait, this is not an ion gun 02-Feb-20 01:19 PM This is a plasma gun 02-Feb-20 01:19 PM No wonder the configuration looked off 02-Feb-20 01:19 PM And they show plasma sheath extraction 02-Feb-20 01:20 PM <__ice9#6039> Hmm I see. Let me find the other one that looked similar. I know that one was an ion gun. One moment. 02-Feb-20 01:21 PM Yeah this is very different if you are looking to get an ion beam vs a plasma flow 02-Feb-20 01:21 PM Do you have the paper for the diagram you posted? 02-Feb-20 01:29 PM <__ice9#6039> Basically I am interested in something a bit like this-- https://phoenixwi.com/neutron-generators/ 02-Feb-20 01:30 PM Are you prepared for the amount of concrete you'll need btw? 02-Feb-20 01:31 PM <__ice9#6039> The diagram posted doesn't really mean much-- it was one of several that looked similar, in this case not quite right 02-Feb-20 01:31 PM <__ice9#6039> Hmm? Water works ok among other things. 02-Feb-20 01:33 PM I was literally going to ask if you were looking to build something like a Phoenix Nuclear BoT neutron source lol 02-Feb-20 01:33 PM Neutrons are not the biggest sheilding problem. 02-Feb-20 01:33 PM <__ice9#6039> Anyway it sounds as though there are no detailed reference designs for compact linac based neutron sources? I have seen some papers in this general direction and it has been in the back of my mind for a while, but I was curious. 02-Feb-20 01:33 PM <__ice9#6039> I'm not sure whether I will try to build one or not. But I wanted to understand more about the landscape. 02-Feb-20 01:34 PM Linac energy is a bit too high unless you want spallation. 02-Feb-20 01:34 PM Yeah radiation is going to be nuts at hundreds of kV at mA beam levels lol 02-Feb-20 01:34 PM Hence in part why I haven't built EXEDA yet lol, need a better setup than current house for safety 02-Feb-20 01:34 PM @__ice9 it really comes down to looking at everything in the field related to beam on target systems. 02-Feb-20 01:36 PM <__ice9#6039> I didn't mean a full linac, just linear acceleration of a beam at voltages sufficient to fuse D-D 02-Feb-20 01:36 PM It's just a high current DC accelerator with deuterium as the ion source lol 02-Feb-20 01:36 PM <__ice9#6039> Am aware of spallation, capital cost is extreme 02-Feb-20 01:37 PM I would research high current guns and injectors in general 02-Feb-20 01:37 PM <__ice9#6039> Right that's what I thought @Applied_Ion 02-Feb-20 01:37 PM Principles will apply the same regardless of ion source, unless you get into some odd stuff like neutral beams or negative ion sources 02-Feb-20 01:38 PM <__ice9#6039> Also-- it seems, unless I am mistaken, that there isn't really an approachable way to keep a neutron generator fairly directional (?). Pretty much everything I have seen sprays them in all directions, requiring much more shielding coverage. 02-Feb-20 01:39 PM There are some directional stuff like DPFs, but for BoT stuff it just goes everywhere 02-Feb-20 01:39 PM <__ice9#6039> ... I forgot DPFs are directional 02-Feb-20 01:39 PM <__ice9#6039> Those are much simpler as well. 02-Feb-20 01:39 PM Ehhh, define simple lol 02-Feb-20 01:39 PM @Mason_Yu is the king of DPFs here lol 02-Feb-20 01:39 PM <__ice9#6039> Two tubes, big pulse cap, papers have parameters to run them 02-Feb-20 01:39 PM <__ice9#6039> Not sure whether the pulses are big enough for neutron imaging and similar though (?) 02-Feb-20 01:40 PM Yeah in theory, but there is a lot of calculation and optimization involved 02-Feb-20 01:40 PM DPF? 02-Feb-20 01:40 PM Dense plasma focus 02-Feb-20 01:40 PM <__ice9#6039> https://en.m.wikipedia.org/wiki/Dense_plasma_focus?wprov=sfla1 02-Feb-20 01:40 PM You should see the work @Mason_Yu is putting into his, it's crazy 02-Feb-20 01:40 PM Ahh, sounds similar to multicaustic. 02-Feb-20 01:41 PM <__ice9#6039> I'm very interested. These are very compact devices as well. 02-Feb-20 01:41 PM DPFs are awesome since you can do so much with them 02-Feb-20 01:41 PM <__ice9#6039> Directionality keeps the shielding smaller too 02-Feb-20 01:41 PM Oh yeah, it's more complicated than you would expect it to be 02-Feb-20 01:41 PM It's not 100% directional 02-Feb-20 01:41 PM Neutron, ion beam, ebeam, x-ray sources, etc 02-Feb-20 01:41 PM You need shielding in all directions 02-Feb-20 01:41 PM For x-rays too 02-Feb-20 01:41 PM Not completely directional, but it's got some directionality, better than BoT lol 02-Feb-20 01:42 PM <__ice9#6039> Sure, x-ray shielding is just lead though. I have a lot of lead and can easily get more. I also have an x-ray device. 02-Feb-20 01:42 PM Also if you just connect a pulse bank to a concentric tube insulated from each other you would likely not even get a pinch 02-Feb-20 01:42 PM <__ice9#6039> Interesting-- go on? 02-Feb-20 01:43 PM Certain conditions need to be met for an effective pinch to occur 02-Feb-20 01:43 PM You first need a stable plasma sheathe formation, which means you need to select the correct insulator material, quartz is the best for small DPFs. Then you need to worry about all the inductances in the system, your bank, your switch, your transmission line and electrode geometry and finally a time-dependent inductance in the plasma sheathe 02-Feb-20 01:43 PM It is critical that your plasma sheathe is accelerated fast enough to compress the neutral gas 02-Feb-20 01:43 PM That is kinda why my project is currently on hold at the moment (plus I'm out of cash and cap banks might not be safe to operate anymore) 02-Feb-20 01:43 PM Also, you need to worry about restrikes and also impurities from electrodes getting into the plasma 02-Feb-20 01:43 PM Remember that high z impurities radiates like crazy and also cause massive resistivity increases 02-Feb-20 01:45 PM <__ice9#6039> Quartz is easy. Lots of experience with it. Have done enough RF and induction heating stuff to understand parasitic inductances and how to minimize them. 02-Feb-20 01:45 PM <__ice9#6039> Reading.... 02-Feb-20 01:45 PM Then you have to make sure mechanically the system is sound 02-Feb-20 01:46 PM <__ice9#6039> I figured just use a thyratron. I have a big ceramic one. 02-Feb-20 01:46 PM Making a quartz tube may be easy to you sure, but making sure it won't shatter? Not so much 02-Feb-20 01:46 PM <__ice9#6039> No I just buy them 02-Feb-20 01:47 PM That's exactly what I did too, but you need mechanical dampening on the insulators too 02-Feb-20 01:47 PM <__ice9#6039> Hmm noted 02-Feb-20 01:47 PM That should go into the feedthrough design 02-Feb-20 01:47 PM <__ice9#6039> Yep want it to be a little bit flexible, noted 02-Feb-20 01:47 PM You've got a hydrogen thyratron? Maximum voltage and current? 02-Feb-20 01:47 PM <__ice9#6039> Deuterium actually 02-Feb-20 01:47 PM <__ice9#6039> Very high 02-Feb-20 01:47 PM Ah I'm using a deuterium thyratron to trigger a spark gap 02-Feb-20 01:48 PM Nowhere near enough for a dpf lol 02-Feb-20 01:48 PM But mine only goes up to like 15 kA peak? Also low rep rates only 02-Feb-20 01:48 PM Thyratron can't handle that current level 02-Feb-20 01:48 PM <__ice9#6039> Interesting. Yeah that's similar. 02-Feb-20 01:48 PM 15 kA is very very low for a DPF 02-Feb-20 01:48 PM <__ice9#6039> Ah I see 02-Feb-20 01:48 PM <__ice9#6039> Ok how does the spark gap work? Just air? 02-Feb-20 01:48 PM So then you need the rep rate 02-Feb-20 01:48 PM Yeah, dpf is in hundreds of kA 02-Feb-20 01:49 PM Yeah for now, but eventually I'd like to move to a low pressure spark gap 02-Feb-20 01:49 PM Most just use self breaking gaps 02-Feb-20 01:49 PM A rail type spark gap 02-Feb-20 01:49 PM Triggering is good for control 02-Feb-20 01:49 PM Self-breaking may not produce the optimal initial ionization conditions, but it could work in a pinch 02-Feb-20 01:49 PM @Mason_Yu don't you mean high pressure gap? 02-Feb-20 01:50 PM <__ice9#6039> I have a trigger circuit I made for laser stuff already, similar thing should work 02-Feb-20 01:50 PM Real hardcore spark gap engineering is an art lol. One of my favorite areas of study 02-Feb-20 01:51 PM <__ice9#6039> Ok, so fast rise-time trigger circuit into an air spark gap between some large copper rods, with nice flat wide straight electrodes from a bank of parallel pulse caps 02-Feb-20 01:51 PM <__ice9#6039> That's pretty similar to a ruby laser anyway 02-Feb-20 01:51 PM <__ice9#6039> Very similar 02-Feb-20 01:51 PM No! I'm referring to something closer to the pseudospark gaps 02-Feb-20 01:51 PM Really? Why? 02-Feb-20 01:51 PM Either that or rail gaps 02-Feb-20 01:51 PM <__ice9#6039> Oh? Intriguing 02-Feb-20 01:51 PM Low inductances 02-Feb-20 01:51 PM Can't beat high pressure gaps for inductance though 02-Feb-20 01:52 PM High pressure rail gaps can deliver high currents but needs to be triggered very specifically to have an even discharge 02-Feb-20 01:52 PM That's not an issue at low rep rates though 02-Feb-20 01:52 PM <__ice9#6039> That sounds like a TEA laser yeah 02-Feb-20 01:53 PM Unless you are referring to multichannel discharge 02-Feb-20 01:53 PM I'm more worried about consistency, I essentially need to have all plasma channels forming evenly across the two rails 02-Feb-20 01:53 PM Yeah exactly 02-Feb-20 01:53 PM Building your own pseudospark gap would be way harder lol 02-Feb-20 01:54 PM <__ice9#6039> >Also, you need to worry about restrikes and also impurities from electrodes getting into the plasma Tungsten/molybdenum better than copper for this then? Or maybe copper-tungsten? 02-Feb-20 01:54 PM Yeah, so perhaps my only DIY option is a high pressure rail gap triggered by a parallel knfe edge 02-Feb-20 01:54 PM Yeah copper tungsten electrode materials 02-Feb-20 01:54 PM Or pure tungsten, if you can machine that 02-Feb-20 01:55 PM That has driven a lot of big physics systems lol. Still does 02-Feb-20 01:55 PM I currently have a OFHC copper anode and copper tungsten cathode 02-Feb-20 01:55 PM <__ice9#6039> I have found that welding electrodes are surprisingly versatile objects, particularly the big fat ones 02-Feb-20 01:55 PM <__ice9#6039> Parallel knife edge? 02-Feb-20 01:55 PM <__ice9#6039> Tungsten sheet metal is also available but costly 02-Feb-20 01:56 PM Well, spark gaps in general 02-Feb-20 01:57 PM Knife edge is the trigger electrode, it sits at some distance in between the two rails but must be perfectly parallel 02-Feb-20 01:57 PM <__ice9#6039> Ah I see 02-Feb-20 01:57 PM <__ice9#6039> Does this involve a chain of resistors like TEA lasers as well? 02-Feb-20 01:58 PM Like the Z-machine sunchronizes so many switches at once with low jitter it's nuts lol I don't think you honestly need to be that worried about it. 02-Feb-20 01:58 PM No, tea lasers use the resistors for preionization of the laser channel 02-Feb-20 01:58 PM <__ice9#6039> Ah right that's arc suppression. This is parallel arcing 02-Feb-20 01:59 PM The biggest systems in the world just use simple spark gap geometries usually 02-Feb-20 01:59 PM Well here using some resistors to preionize the plasma across your cylindrical electrodes is actually useful 02-Feb-20 01:59 PM Not for the spark gap, for the DPF 02-Feb-20 02:00 PM Only ultrafast stuff like subnanosecond drivers at hundreds of kV need really insane gap design 02-Feb-20 02:00 PM If you want garaunteed multichannel breakdown and don't mind tons of work after each shot you can go with solid dielectric gap switches lol 02-Feb-20 02:02 PM Uhh that would be a bit too much work for me I think 02-Feb-20 02:02 PM Gotta replace the switch each shot, but you can deliver MA currents easy lol 02-Feb-20 02:02 PM Bit too much for my wallet too 02-Feb-20 02:02 PM Just basic hardware store stuff 02-Feb-20 02:02 PM Uhh I want to get out of school, but then I'll lose a place to work on this 02-Feb-20 02:03 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1118327-31840.pdf 02-Feb-20 02:03 PM <__ice9#6039> Looks like cap bank voltages are usually pretty high as well compared to lasers 02-Feb-20 02:03 PM Ahh the US government now owns the world's largest DPF 02-Feb-20 02:03 PM <__ice9#6039> That's inconvenient. Caps are costly. 02-Feb-20 02:03 PM Probably the same level. Few tens of kV for both DPFs and lasers 02-Feb-20 02:03 PM 10^14 neutrons per shot I think 02-Feb-20 02:03 PM <__ice9#6039> Better not to have separate ones 02-Feb-20 02:03 PM <__ice9#6039> Lasers usually just a couple kV for flashtubes 02-Feb-20 02:04 PM It's generally above 10kV, but you can make low voltage banks work too 02-Feb-20 02:04 PM Oh I'm talking about high power pulsed eximer 02-Feb-20 02:04 PM Like up to 30kV with magnetic pulse compressors 02-Feb-20 02:05 PM <__ice9#6039> >Gotta replace the switch each shot, but you can deliver MA currents easy lol Make the dielectric move through the gap 02-Feb-20 02:05 PM It essentially means a longer electrode for the DPF. Upper voltage limit is likely set by instabilities of the breakdown and requirement of high current 02-Feb-20 02:05 PM <__ice9#6039> Ah yeah excimer lasers are much.. bigger in general 02-Feb-20 02:05 PM <__ice9#6039> That's very useful to know re: voltage 02-Feb-20 02:05 PM <__ice9#6039> May be a bit easier to attain huge current that way also 02-Feb-20 02:06 PM But low voltage also means a lot of other issues, resistive dissipation is actually very significant loss of energy 02-Feb-20 02:06 PM <__ice9#6039> Yes at MA 02-Feb-20 02:06 PM During the rundown and also the radial compression phase 02-Feb-20 02:07 PM <__ice9#6039> Ran into that issue with induction heater design at just like a kA 02-Feb-20 02:07 PM MA is really beyond any amateur efforts 02-Feb-20 02:07 PM Well, depends 02-Feb-20 02:07 PM <__ice9#6039> Wide copper plates 02-Feb-20 02:07 PM For DPFs I mean 02-Feb-20 02:07 PM <__ice9#6039> But yeah need lots of caps 02-Feb-20 02:07 PM The size and shielding requirement is just way too large 02-Feb-20 02:08 PM Yeah lol. Large ns transmission line generator could be done at home delivering a MA into a very low impedance load 02-Feb-20 02:08 PM <__ice9#6039> Arranged like a Shiva Star type bank layout to minimize inductance 02-Feb-20 02:08 PM Yeah, that's how all high current DPFs are built 02-Feb-20 02:08 PM I think Shiva Star was even used as a DPF once? 02-Feb-20 02:08 PM <__ice9#6039> Pretty sure 02-Feb-20 02:08 PM <__ice9#6039> Yes 02-Feb-20 02:08 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580681424761-B3198.png 02-Feb-20 02:08 PM <__ice9#6039> That's still just 6MA? 02-Feb-20 02:08 PM <__ice9#6039> Then MA is very likely unattainable on small scale 02-Feb-20 02:11 PM At 120 kV though 02-Feb-20 02:11 PM <__ice9#6039> Yes, true 02-Feb-20 02:11 PM <__ice9#6039> Smaller cap charge, but it should move faster 02-Feb-20 02:11 PM And you really don't want that big of anything anyway. Just too dangerous 02-Feb-20 02:11 PM <__ice9#6039> Oh obviously lmao 02-Feb-20 02:11 PM <__ice9#6039> Too expensive 02-Feb-20 02:11 PM <__ice9#6039> No one is proposing replicating a major national lab installation 02-Feb-20 02:11 PM <__ice9#6039> Hmm anyway, did you get any particle beams? 02-Feb-20 02:13 PM No, not yet, currently held up by the swelling cap banks 02-Feb-20 02:13 PM With no replacement in sight... 02-Feb-20 02:13 PM Well I do have replacements but I just can't afford to buy it... 02-Feb-20 02:14 PM <__ice9#6039> ... swelling 02-Feb-20 02:14 PM <__ice9#6039> x_x 02-Feb-20 02:15 PM Well that and also way too busy with classes 02-Feb-20 02:15 PM Other projects like the SEM is not helping 02-Feb-20 02:16 PM <__ice9#6039> @Applied_Ion so would a pulse forming network make it possible to ignite a DPF at lower total cap bank energy? 02-Feb-20 02:16 PM <__ice9#6039> Yeah SEMs are very complex.... 02-Feb-20 02:17 PM The good thing about a DPF is that you don't need a PFN. The whole point is to transfer the cap bank energy into magnetic energy during the run down and then create the pinch 02-Feb-20 02:17 PM So essentially the rundown phase is kinda like a PFN, a time-dependent PFN 02-Feb-20 02:18 PM <__ice9#6039> Ah yeah I could see that 02-Feb-20 02:18 PM You can make tiny DPFs with tiny cap banks, even portable ones 02-Feb-20 02:18 PM <__ice9#6039> Then the effort mostly resolves to cap bank arrangement and an extremely high current spark gap 02-Feb-20 02:19 PM But no PFNs necessary 02-Feb-20 02:19 PM I don't see the benefit to a 10^4 per shot neutron source (with lots of shot-to-shot variations) that still require a vacuum system though 02-Feb-20 02:19 PM It's neat, but a fusor will easily beat that, you want to exploit the yield proportional to I^3.8 scaling law 02-Feb-20 02:22 PM <__ice9#6039> Yes that was in the presentation I posted here 02-Feb-20 02:22 PM <__ice9#6039> Hmm I see. The trouble with BoT is that the neutrons end up going every which way, which means the entire thing needs to be in a water tank or wax castle 02-Feb-20 02:23 PM This is as far as I know the largest DPF ever built 02-Feb-20 02:23 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-EC39B.png 02-Feb-20 02:23 PM <__ice9#6039> Pretty 02-Feb-20 02:23 PM Quite compact huh? Until you see the massive cap bank and switches 02-Feb-20 02:24 PM <__ice9#6039> I'm surprised those cables have low enough inductance to work, but at least it's pretty well matched inductance 02-Feb-20 02:24 PM <__ice9#6039> Would have expected a massive bus bar plate 02-Feb-20 02:25 PM Yeah, and they put a switch on each bank, inductance drop with more connected in parallel 02-Feb-20 02:25 PM <__ice9#6039> Hmm but yes, doing neutron imaging or any kind of interesting transmutation needs rather more than 10^4 02-Feb-20 02:25 PM <__ice9#6039> Is it possible to breed enough tritium in situ to get a meaningful increase in neutron yields? 02-Feb-20 02:25 PM <__ice9#6039> I kind of doubt it, but it's an interesting thought 02-Feb-20 02:29 PM No, the reaction is way too fast, but breeding can be done in the same manner as in tokamaks 02-Feb-20 02:29 PM I.e breed in a blanket and extract, reprocess to fuel the next shot 02-Feb-20 02:29 PM Not in-situ, everything is done within tens of nanoseconds 02-Feb-20 02:30 PM <__ice9#6039> Oh I meant from mixing the lithium into the same target 02-Feb-20 02:30 PM <__ice9#6039> And firing into it repeatedly 02-Feb-20 02:30 PM <__ice9#6039> Analogous to Castle Bravo 02-Feb-20 02:30 PM <__ice9#6039> Actually I don't see why that wouldn't work 02-Feb-20 02:31 PM I don't know, but I think it would disrupt the pinch quite significantly, bremstrahlung losses will increase by a lot 02-Feb-20 02:31 PM <__ice9#6039> Oh for DPF it's a different issue 02-Feb-20 02:31 PM <__ice9#6039> It's as you wrote 02-Feb-20 02:31 PM <__ice9#6039> I was thinking for BoT 02-Feb-20 02:32 PM Oh yeah it should be possible? But why not just use tritium gas target? 02-Feb-20 02:32 PM <__ice9#6039> Because tritium is expensive and difficult regulatorily to obtain in meaningful quantities 02-Feb-20 02:32 PM You have to deal with tritium processing license issues either way 02-Feb-20 02:32 PM Well breeding in-situ will still generate a lot of tritium left over in the system, and NRC will want to know about that 02-Feb-20 02:33 PM <__ice9#6039> Hmm probably true. 02-Feb-20 02:33 PM <__ice9#6039> It definitely wouldn't all burn up again 02-Feb-20 02:33 PM <__ice9#6039> So that would not really avoid the issue 02-Feb-20 02:36 PM At low beam currents you can consider plastics with implanted deuterium and add lithium to the mix 02-Feb-20 02:36 PM <__ice9#6039> Hmm from a cost and compactness standpoint, something like the Phoenix BoT probably wins out, but directionality is troublesome 02-Feb-20 02:37 PM Yeah, fingers crossed, doing my third interview with Phoenix next Tuesday 02-Feb-20 02:37 PM <__ice9#6039> Or just straight up lithium deuteride. 02-Feb-20 02:37 PM <__ice9#6039> Ordinary natural lithium is only 50% worse apparently https://inis.iaea.org/search/search.aspx?orig_q=RN:38053222 02-Feb-20 02:37 PM <__ice9#6039> Vs Li-6 02-Feb-20 02:37 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200202-164128-3E217.png 02-Feb-20 02:37 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200202-164122-FCDAA.png 02-Feb-20 02:37 PM <__ice9#6039> Few hundred kV at a few kW 02-Feb-20 02:37 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200202-164644-53377.png 02-Feb-20 02:37 PM <__ice9#6039> For imaging, waiting a few hours would match a large DPF pulse. Maybe days given more isotropic emission. 02-Feb-20 02:37 PM <__ice9#6039> Seems obvious that even higher voltages would be useful though 02-Feb-20 02:50 PM Also for imaging or other applications where you only care about the the flux, then the directionality of DPFs would be useful 02-Feb-20 02:50 PM The pulsed x-rays can also be filtered out in time 02-Feb-20 02:53 PM <__ice9#6039> Yes, that's true, but the I^4 scaling makes things very difficult if you don't have the resources for huge volumes of caps 02-Feb-20 02:53 PM Swap out the fill gas to argon or neon and you get a massive flash x-ray source too! Makes a multi-purpose imaging set-up 02-Feb-20 02:53 PM <__ice9#6039> Huh. That's actually very interesting in its own right. 02-Feb-20 02:54 PM Though actually x-ray energies are quite low here, and there's a large energy spread 02-Feb-20 02:54 PM <__ice9#6039> What kind of keV distribution? 02-Feb-20 02:54 PM <__ice9#6039> Ah hmm 02-Feb-20 02:54 PM <__ice9#6039> Was hoping to inspect welds etc 02-Feb-20 02:54 PM Go with a pulsed ion diode accelerator. In between CW BoT and DPF lol 02-Feb-20 02:54 PM Mostly the ionization shell energies of the fill gas, like argon k-line at 3 KeV 02-Feb-20 02:55 PM just get a pulsed x-ray system if you want to do super thick x-ray stuff 02-Feb-20 02:55 PM they're a dime a dozen on ebay 02-Feb-20 02:55 PM So like a few keVs 02-Feb-20 02:55 PM very high death per pulse ratio 02-Feb-20 02:56 PM <__ice9#6039> As in, the device tends to fail...? 02-Feb-20 02:56 PM no, as in you tend to fail if you eat too many pulses with your body 02-Feb-20 02:56 PM I think you should give up on any idea of transmutation @__ice9 you will have lethally high radiation long before you have the capability to make anything you can see with a microscope. 02-Feb-20 02:56 PM the higher end ones can output over a Sv/min 02-Feb-20 02:57 PM <__ice9#6039> None of this is for biological applications, and I mentioned transmutation only in passing. 02-Feb-20 02:57 PM <__ice9#6039> Why on Earth would anyone stand in front of such a thing 02-Feb-20 02:57 PM <__ice9#6039> Specifically, the point on transmutation had to do with lithium deuteride 02-Feb-20 02:58 PM the trick is that they output a very wide cone 02-Feb-20 02:58 PM usually over 100 degrees, sometimes over 180 02-Feb-20 02:58 PM <__ice9#6039> Yes obviously-- in front 02-Feb-20 02:58 PM or behind 02-Feb-20 02:58 PM you don't want to be near one when it's running, at all 02-Feb-20 02:59 PM <__ice9#6039> I don't even run lasers in the same room, much less x-ray equipment. It would need more lead, and that's fine. But such things are best handled with a remote camera and wireless trigger switches 02-Feb-20 02:59 PM yup 02-Feb-20 02:59 PM except a lot more lead than lasers ;P 02-Feb-20 03:00 PM Where do you get your lead for cheap? @__ice9 02-Feb-20 03:00 PM <__ice9#6039> I meant more than the normal x-ray head I have 02-Feb-20 03:00 PM Don't tell me gun ranges 02-Feb-20 03:00 PM <__ice9#6039> eBay 02-Feb-20 03:00 PM but you can get NDT heads that output 320kv or higher 02-Feb-20 03:00 PM <__ice9#6039> That's the idea 02-Feb-20 03:00 PM which is scary 02-Feb-20 03:00 PM <__ice9#6039> It's useful 02-Feb-20 03:00 PM and scary 02-Feb-20 03:00 PM <__ice9#6039> For looking through metal 02-Feb-20 03:00 PM <__ice9#6039> But of course 02-Feb-20 03:00 PM <__ice9#6039> It needs more metal to attenuate it afterward 02-Feb-20 03:00 PM <__ice9#6039> Though, less than you might think 02-Feb-20 03:01 PM there are CW bipolar heads too 02-Feb-20 03:01 PM +160, -160 02-Feb-20 03:01 PM in fact there's often COMET-branded heads(with no PSUs) often on ebay for under $200 02-Feb-20 03:01 PM good luck powering it at home though 02-Feb-20 03:02 PM <__ice9#6039> I can make +/- 160 at a few mA 02-Feb-20 03:02 PM <__ice9#6039> kV 02-Feb-20 03:02 PM @__ice9 what sort of looking through metal/weld inspection are you doing where the already available xray/gamma cameras wont do? 02-Feb-20 03:02 PM they usually want around 1.5-6kW 02-Feb-20 03:02 PM <__ice9#6039> That's just 2x CW multipliers 02-Feb-20 03:02 PM <__ice9#6039> That's what I would expect 02-Feb-20 03:02 PM <__ice9#6039> Um those are very costly 02-Feb-20 03:03 PM C-arm cameras! 02-Feb-20 03:03 PM big, often ignored by sellers 02-Feb-20 03:03 PM you can rent them fairly inexpensively from what little i know about it? 02-Feb-20 03:03 PM almost always big x-ray intensifiers 02-Feb-20 03:03 PM Bipolar power might make it difficult to power the ion source. The Am Sci did it with a battery in the terminal. 02-Feb-20 03:04 PM <__ice9#6039> You can rent most things if you do enough paperwork. 02-Feb-20 03:04 PM thats probably the hold up then lol 02-Feb-20 03:07 PM <__ice9#6039> You could respond to literally anyone here with 'lol just rent one'. It isn't very informative, it doesn't teach anyone anything new, and it makes it into an economic status discussion instead of a technology one. I don't think that's very helpful. 02-Feb-20 03:09 PM i asked what you wanted to do that the already available ones did not and you responded about the cost so i was trying to find out if cost was the only reason not to consider renting one or not 02-Feb-20 03:09 PM <__ice9#6039> I like having interesting tools available. That's all. 02-Feb-20 03:17 PM <__ice9#6039> @Mason_Yu what about dielectric breakdown gaps using water instead of a solid? 02-Feb-20 03:19 PM It could create a small detonation with powerful shockwaves as spark channels are formed between the gaps. Why do you want that anyway? 02-Feb-20 03:19 PM High pressure spark gaps filled with dry nitrogen or SF6 seems less dangerous 02-Feb-20 03:19 PM Also as you fire the gap the water may become conductive, and you may not be able to hold off voltage anymore 02-Feb-20 03:23 PM Water gaps are certainly a switching method, not really useful here in this application. You usually see them used maybe in conjunction with water insulated pulse forming lines 02-Feb-20 03:23 PM You definitely would need to run a deionizer with it 02-Feb-20 03:23 PM <__ice9#6039> @Spirit a pulsed x-ray system could be operated from a Marx generator, right? 02-Feb-20 03:24 PM Most are lol 02-Feb-20 03:24 PM yeah 02-Feb-20 03:24 PM a lot are also operated using pulsed transformers 02-Feb-20 03:24 PM Real flash x-ray generators in physics usually have at least a Marx stage 02-Feb-20 03:24 PM Usually to pulse charge a fast line for driving them though 02-Feb-20 03:24 PM But you can drive flash x-ray systems with marxes fine 02-Feb-20 03:25 PM Most flash x-ray systems use spiral generators I thought. 02-Feb-20 03:26 PM yeah 02-Feb-20 03:26 PM NDT ones do 02-Feb-20 03:26 PM No, spiral generators are not very common, not for real flash x-ray systems 02-Feb-20 03:26 PM they're not flash x-ray, they're just explosive emission pulsed systems 02-Feb-20 03:26 PM not what you'd call flash x-ray in a lab 02-Feb-20 03:26 PM In general Russian design opts for pulsed Tesla transformers while US/British go for Marx banks 02-Feb-20 03:26 PM Yes, flash x-ray uses explosive emission lol 02-Feb-20 03:27 PM emphasis on "just" 02-Feb-20 03:27 PM Flash x-ray are used with high power explosive emission lol 02-Feb-20 03:27 PM yes 02-Feb-20 03:31 PM <__ice9#6039> @Mason_Yu the water comment was a further reflection after @Applied_Ion mentioned solid dielectric spark gaps, but yes something non-aqueous but still having little tendency to chemically react to a stable product in the arc might work better. SF6 is probably the most obvious candidate. 02-Feb-20 03:31 PM Or dry air in a pinch 02-Feb-20 03:32 PM <__ice9#6039> My other thought on solid dielectrics had to do with a wide moving tape on a reel 02-Feb-20 03:32 PM <__ice9#6039> That gets punched through successively without needing rebuild 02-Feb-20 03:32 PM A lot depends on system configuration. Usually you see liquid gaps where there is a liquid insulated line and transition to a vacuum load. Solid gaps are super old tech, not really used anymore. High pressure gas has the fastest pulse potential 02-Feb-20 03:33 PM <__ice9#6039> Ah that explains 02-Feb-20 03:34 PM At these high current levels these high pressure spark gaps need to be taken apart regularly for cleaning and maintenance. Everything erodes and moves 02-Feb-20 03:34 PM <__ice9#6039> Also true. 02-Feb-20 03:34 PM <__ice9#6039> Another good application for copper tungsten probably 02-Feb-20 03:34 PM <__ice9#6039> Or liquid contacts 02-Feb-20 03:35 PM Fastest generator is the Russian RADAN system. Some configurations up to 3000psi hydrogen. With subnanosecond pulse slicing gaps it can achieve hundreds of kV with a few hundred ps FWHM. Actually runaway emission ebeams operating with atmospheric diode guns require like sub-100pS several hundred kV pulses to operate 02-Feb-20 03:35 PM <__ice9#6039> Fascinating 02-Feb-20 03:36 PM You don't need to take apart pressurized gaps too often at low rep rates 02-Feb-20 03:44 PM <__ice9#6039> https://www2.l3t.com/ati/solutions/irs_flash_x-ray.htm Yes it looks like flash x-ray commonly operates at hundreds of kV 02-Feb-20 03:44 PM <__ice9#6039> Widely used for weapons research because of its speed and trigger precision, but the ability to use a cheap Marx instead of a more costly CW is useful 02-Feb-20 03:51 PM CW can't get the flux that pulsed can. You have to operate that high of using a metal cathode anyway, which requires fast high field gradients. Usually in weapons it's for hydrodynamic studies during detonation, which requires fast stuff, or for gamma Ray simulation for the highest power generators 02-Feb-20 03:51 PM Other cathodes can get emission at lower voltages though, but you never see that in small systems, usually only massive generators. Most small or sealed stuff operates with metal 02-Feb-20 03:53 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/mattsson1972-7BBB3.pdf 02-Feb-20 03:53 PM <__ice9#6039> Amusingly simple cathode designs 02-Feb-20 03:54 PM Yeah flash tubes are stupid simple 02-Feb-20 03:54 PM JC Martin famously made one using a fork and spoon for electrodes in a plastic container pumped to high vacuum, with the interface in an atmosphere of SF6 02-Feb-20 03:56 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580687726965-C8668.png 02-Feb-20 03:56 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580687747767-83398.png 02-Feb-20 03:56 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580687761643-E3108.png 02-Feb-20 03:56 PM <__ice9#6039> That's hilarious 02-Feb-20 03:56 PM <__ice9#6039> Yeah this one notes just dunking it in transformer oil 02-Feb-20 03:56 PM <__ice9#6039> Dental x-ray heads are also oil filled generally 02-Feb-20 03:56 PM <__ice9#6039> Of course, this also hints at the rather poorer directionality, but that can be forcibly collimated with shielding material nearby. 02-Feb-20 03:59 PM They can be highly directional depending on design 02-Feb-20 04:00 PM <__ice9#6039> Details? 02-Feb-20 04:00 PM <__ice9#6039> I see all these massive CT scanner tubes online and wonder why 02-Feb-20 04:00 PM <__ice9#6039> Ah I see. Found an IMA2-150D that explains more in the description. Yes this would be very suitable for looking through metals. 02-Feb-20 04:09 PM soviet IMA tubes are not oil submerged 02-Feb-20 04:09 PM they are stuck into a PTFE connector 02-Feb-20 04:09 PM at least as far as I've seen them 02-Feb-20 04:09 PM if you want a smaller one, get an IMA2-150D 02-Feb-20 04:09 PM but not for those awful prices 02-Feb-20 04:09 PM they can be often found for less than $100 02-Feb-20 04:14 PM <__ice9#6039> Yes I expected as much 02-Feb-20 04:14 PM <__ice9#6039> Would actually prefer a larger one, at least 200kV 02-Feb-20 04:14 PM then the 320d is your only option 02-Feb-20 04:15 PM <__ice9#6039> Hmm I see, will see if other listings exist elsewhere 02-Feb-20 04:20 PM there are western pulse tubes too 02-Feb-20 04:20 PM though they're more droopy and longer, not bulb-shaped 02-Feb-20 04:21 PM would something with as large a focal spot as those tubes being discussed have be useful for what the end goal is here? 02-Feb-20 04:22 PM you can always add distance 02-Feb-20 04:22 PM i thought those are for imaging pretty large objects (1m or so) in their as designed use 02-Feb-20 04:22 PM for weld inspection i think he needs one of those microfocus tubes? not really sure but that was my basic understanding of that sort of thing 02-Feb-20 04:23 PM these are primarily for weld inspection 02-Feb-20 04:23 PM but you do need a large distance to the subject 02-Feb-20 04:25 PM http://lampes-et-tubes.info/xr/xr120.php?l=e 2mm tube onto a tungsten window...so 2.5-3mm focal spot? 02-Feb-20 04:25 PM yup 02-Feb-20 04:25 PM hope you do not have any neighbors if you are running that 02-Feb-20 04:26 PM they're made for pipelines 02-Feb-20 04:26 PM and others 02-Feb-20 04:26 PM <__ice9#6039> Interesting paper 02-Feb-20 04:26 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200202-182458-29998.png 02-Feb-20 04:26 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200202-182504-15FD5.png 02-Feb-20 04:34 PM Yeah pretty standard lol. There are so many papers on flash x-ray tubes it's nuts. They all essentially boil down to the same basic principles though 02-Feb-20 04:34 PM The drivers for them are all basic pulsed power stuff too, used for countless physics systems besides x-ray. 03-Feb-20 10:47 AM @__ice9 did you mention your plans for capturing your xray images and I missed it or did it not come up? would be interested to hear some more information on that side of things 03-Feb-20 10:47 AM also very encouraging when you ask a seller about the window on something and they say "The sensor has no window." 03-Feb-20 12:51 PM <__ice9#6039> Oh you can just use a remote camera and an old x-ray phosphor screen 03-Feb-20 12:51 PM <__ice9#6039> You need a little easel or something similar to hold it up behind the target and a tripod for the camera, but that's it. Just be sure to shield behind the target or point it such that it hits a bunch of concrete or the ground 03-Feb-20 12:51 PM <__ice9#6039> A few mm of lead shielding is enough if that isn't convenient. You don't really need very thick lead for <100kV 03-Feb-20 12:51 PM <__ice9#6039> When you are trying to shield fairly powerful gamma emitters then you start needing multiple cm of it though 03-Feb-20 12:51 PM <__ice9#6039> I am still not seeing a flash x-ray tube for under $150 that can do 300kV, which is a bit annoying 03-Feb-20 12:51 PM <__ice9#6039> Though I suppose the Nixie tube experimenters would know a thing or two about making such objects 03-Feb-20 12:58 PM @Charles made commercial x-ray tubes 03-Feb-20 01:00 PM X ray tubes are not cheap. You need very expensive glass and generally the Beryllium window alone and you are in the big bucks right there. Used/surplus of probably the best route 03-Feb-20 01:01 PM ahh i was hoping you had some fancy but cheap new way i was unware of for the image capturing 03-Feb-20 01:02 PM My knowledge ends with 50’s technology as far as X ray tubes. I know there is newer designs out there but I have no experience with them. 03-Feb-20 03:17 PM <__ice9#6039> A 300kV tube does not need a beryllium window. Such things are not used for XRF. Only imaging through metal and ceramic. 03-Feb-20 03:17 PM <__ice9#6039> Regarding image capture, the 'nice' way is to use a giant panel CCD that sits up against the phosphor screen to capture the image from it glowing 03-Feb-20 03:17 PM <__ice9#6039> But unfortunately they are all proprietary as far as I can tell. 03-Feb-20 03:17 PM <__ice9#6039> The XRF dataset I used to make some software for interpreting spectra is all at 40kV 03-Feb-20 03:17 PM <__ice9#6039> Hmm anyway, understandable. Flash x-ray tubes use a different design for pulsed operation. I have no experience with vacuum glasswork. 03-Feb-20 03:17 PM <__ice9#6039> https://m.youtube.com/watch?v=Ifc2ADSG4CI This is a pretty neat overview though 03-Feb-20 03:17 PM <__ice9#6039> New to me, though probably not to most people here 03-Feb-20 03:26 PM glasslinger has some good stuff on that too 03-Feb-20 03:26 PM he made an xray tube at one point 03-Feb-20 03:27 PM <__ice9#6039> Ah interesting 03-Feb-20 03:27 PM I have talked to him about vacuum systems and glasswork before but not lately 03-Feb-20 03:27 PM think he just used a tungsten target with an angular face milled on it in a glass envelope 03-Feb-20 03:27 PM not sure if that can handle the voltages you want 03-Feb-20 03:27 PM https://www.youtube.com/watch?v=-0G4-JicCIw 03-Feb-20 03:32 PM glasslinger's work is lovely 03-Feb-20 03:32 PM ... @__ice9 are you specifically looking for a 300 kVp pulsed x-ray tube? or just talking about them 03-Feb-20 03:35 PM <__ice9#6039> I might like one, but the only one I see on eBay is $360 or something from Europe 03-Feb-20 03:35 PM <__ice9#6039> So, thinking a bit about how flash x-ray tubes are made. 03-Feb-20 03:35 PM <__ice9#6039> Running a flash x-ray tube with a Marx generator seems to be the simplest way to get harder x-rays for imaging metals and ceramics 03-Feb-20 03:35 PM <__ice9#6039> Watching this video next-- much appreciated! 03-Feb-20 03:35 PM <__ice9#6039> Interesting-- he notes that tungsten glass to metal seals are more challenging than the wiki article had suggested 03-Feb-20 03:35 PM <__ice9#6039> The point on uranium glass is also interesting 03-Feb-20 03:35 PM <__ice9#6039> Thoriated tungsten is a favorite of mine 03-Feb-20 03:35 PM <__ice9#6039> Ah yeah tungsten is brittle below 150C. Neat trick if you want to bend it-- just heat it dull red and go slow 03-Feb-20 03:45 PM Speaking of x-rays and directionality... Some years ago I asked this question: https://physics.stackexchange.com/questions/105046/direction-of-x-rays-from-x-ray-tube Is it still correct, that xray are emitted everywhere, and then only partially absorbed by the target cut at an angle? 03-Feb-20 03:46 PM <__ice9#6039> Too much hotter and it will oxidize pretty badly though 03-Feb-20 03:46 PM <__ice9#6039> Yeah they just get blocked by the tungsten mainly 03-Feb-20 03:46 PM <__ice9#6039> And then an entire x-ray head will also have usually a lead or similar dense metal sheet with a slot or rectangle cut in it to serve as a collimator 03-Feb-20 03:49 PM yup 03-Feb-20 03:49 PM considers trying to put a geant4 simulation together for a dummy x-ray head 03-Feb-20 03:49 PM gotta get started with that hulking monstrosity somehow 03-Feb-20 03:51 PM <__ice9#6039> Lead sheets are affordable and very easy to work with, so if you are building an x-ray device, you can just wrap all the directions you want to block with lead and then set up your collimator in the direction of the angled part of the anode 03-Feb-20 03:51 PM that's an important trick people overlook 03-Feb-20 03:51 PM before you start shielding your device, shield your tube! 03-Feb-20 03:52 PM <__ice9#6039> Was very amused by your Czochralski washing machine furnace comment @qualia 03-Feb-20 03:52 PM especially if you only need a tiny beam 03-Feb-20 03:52 PM <__ice9#6039> Am currently building a graphite furnace in a huge stainless steel stockpot lol 03-Feb-20 03:53 PM @__ice9 When building my x-ray unit I cast concrete shield instead, as it is not conductive. Probably too brutal solution. 03-Feb-20 03:55 PM it takes a whole lot of concrete to match the equivalent lead HVL/TVL 03-Feb-20 03:55 PM but it sure is cheap 03-Feb-20 03:55 PM i have a little 50kVp microfocus tube that needs a chassis/oil cooling/etc, and CA specifies certain thresholds for radiation-emission-at-the-surface-of-the-thing that i'd like to try and calculate and follow 03-Feb-20 03:58 PM I have 5cm of concrete for 50kV 03-Feb-20 03:59 PM both voltage and current need to be considered when designing shielding, which is what makes flash radiography kind of a scarier hobbyist proposition -- 300kVp at a couple hundred+ amps from a beefy marx generator sounds like 'building permits for pouring a vault' kind of territory 03-Feb-20 04:00 PM Then 5mA max ) 03-Feb-20 04:01 PM Yeah that's why when I first researched x-raying stuff I decided that I would never have a pulse tube anywhere but raw on a shelf as a display piece 03-Feb-20 04:02 PM shame the old RadPro online calculator isn't up anymore 03-Feb-20 04:02 PM probably got liability'd offline 03-Feb-20 04:02 PM A hundred pulses from the fabled(and ridiculously easy to buy) Soviet/Russian ARINA pulsed system is enough to give you one or two lethal doses 03-Feb-20 04:02 PM The highest end models drop that to just 10-20 pulses 03-Feb-20 04:02 PM And they can pulse at many Hz 03-Feb-20 04:03 PM i found some lovely MCNP calculations of a similarly-sized dense plasma focus to the one i was planning to build, and they figured out exposure at a couple of points 03-Feb-20 04:03 PM believe the fatal dose, unshielded, was somewhere in the realm of three firings 03-Feb-20 04:03 PM And what is even worse is that pulsed x-ray exposure is far worse than prolonged slow exposure 03-Feb-20 04:03 PM Because you get all the damage, right now 03-Feb-20 04:04 PM and this is why that project's been backburnered :D 03-Feb-20 04:05 PM <__ice9#6039> Interesting -- video notes that uranium glass has similar working properties to borosilicate 03-Feb-20 04:05 PM It does! 03-Feb-20 04:05 PM Some tubes beaded the electrodes with uranium glass 03-Feb-20 04:05 PM If you ever see green rings around electrode seals, that's it 03-Feb-20 04:06 PM DPFs are neat bc the axial magnetic self-acceleration means you put 25kV in and get a cone of 450 keV electron beams out, and similarly angry ions all over creation 03-Feb-20 04:06 PM <__ice9#6039> @ZeptoBars insulating against 100kV is a lot easier than you might realize. Potting epoxy is your friend. 03-Feb-20 04:06 PM <__ice9#6039> 30kV/mm 03-Feb-20 04:06 PM neon filled ones are apparently pretty solid flash radiography sources of their own 03-Feb-20 04:06 PM And as for a regional/local suggestions for @ZeptoBars 03-Feb-20 04:06 PM Виксинт ПК-68 или Пентэласт-711 03-Feb-20 04:06 PM (we're close so this is only really relevant to him) 03-Feb-20 04:06 PM Super cheap, high voltage electrical silicone 03-Feb-20 04:07 PM <__ice9#6039> That spring loaded lathe chuck looks really nice for glasswork 03-Feb-20 04:07 PM <__ice9#6039> The Tesla coil leak check is great 03-Feb-20 04:07 PM <__ice9#6039> Oh haha it's a handheld one. Wonder what that was sold as ^^ 03-Feb-20 04:07 PM <__ice9#6039> Nice little tube annealing oven too. Looks useful. 03-Feb-20 04:07 PM <__ice9#6039> Lol "asbestos cover" 03-Feb-20 04:09 PM i have one 'o those, it was sold as a violet wand at a local high-end adult toy store 03-Feb-20 04:09 PM i've used it more for science goofery than anything else tho 03-Feb-20 04:10 PM than anything else 03-Feb-20 04:10 PM they are sold as 'leak testers' 03-Feb-20 04:10 PM it's fun at parties & conventions :D 03-Feb-20 04:10 PM 'does anyone here have any current or family history of heart problems? no? great! someone turn the lights off :D' 03-Feb-20 04:11 PM <__ice9#6039> Nice handheld induction heater too 03-Feb-20 04:11 PM "does anyone here have a hearing aid or defibrillator?" 03-Feb-20 04:11 PM <__ice9#6039> Very clever way to handle the getter. 03-Feb-20 04:11 PM he has plans for that on his website afaik 03-Feb-20 04:11 PM http://tubecrafter.com/tubecrafter_016.htm 03-Feb-20 04:12 PM There's a really easy way to make a tiny(palmtop), but very powerful(>100W) induction heater with like 5 components 03-Feb-20 04:12 PM most of which are tank caps 03-Feb-20 04:12 PM oop plans are on the next page 03-Feb-20 04:13 PM i bought a teeny 300W ZVS module for a couple bux on amzn on a lark and my only regret is i didn't get one of the >=1kW ones 03-Feb-20 04:13 PM <__ice9#6039> Ah so the way to break a vacuum connection with hot glass is to twist it a few times, was wondering about that. 03-Feb-20 04:13 PM you don't have to twist but it helps 03-Feb-20 04:13 PM you just have to melt it slowly enough for the atmospheric pressure to collapse it 03-Feb-20 04:13 PM instead of blowing through 03-Feb-20 04:14 PM yeah i love that air pressure pinches it shut 03-Feb-20 04:14 PM so satisfying 03-Feb-20 04:14 PM youtube needs more scientific glassworking channels 03-Feb-20 04:15 PM scientific glassworkers seem intent on keeping their dark arts secret 03-Feb-20 04:15 PM the How It's Made episode with some was great but it was just one segment 03-Feb-20 04:19 PM I intend on showing the stuff I learn when making tubes 03-Feb-20 04:19 PM eventually 03-Feb-20 04:21 PM <__ice9#6039> Hmm his spot welder works better than mine. Mine is capacitive. It will blast things into place if precision isn't needed and overpenetration is ok, sheet metal etc for instance, but I've had a lot of trouble making it work on tungsten wire. His is merely high current low voltage. Should consider making one like that. 03-Feb-20 04:21 PM <__ice9#6039> Tbf better contact surfaces also though 03-Feb-20 04:30 PM <__ice9#6039> Interesting point on driving x-ray tubes 03-Feb-20 04:30 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580776052441-E2FB3.png 03-Feb-20 04:30 PM <__ice9#6039> Well small XRF ones anyway 03-Feb-20 04:30 PM that's how all hv supplies work 03-Feb-20 04:30 PM aside from the tv flyback 03-Feb-20 04:31 PM <__ice9#6039> The getter is apparently just a barium ring from an old TV tube 03-Feb-20 04:31 PM yeah he scavenges getters 03-Feb-20 04:32 PM @qualia Try out OpenMC for x-ray dose calculation! But it sounds like a manual calculation shouldn't be too difficult in your case? 03-Feb-20 04:32 PM Fluka and Geant4 are made for really high energy stuff and also for detector development, so I've found it's easy to do things incorrectly and get ridiculous answers without knowing what caused it 03-Feb-20 04:35 PM <__ice9#6039> @Spirit re: shielding, effectiveness is approximately exponential in shielding material thickness. So yes it would need a lead casting, but if it's buried in enough epoxy it's perfectly safe to place it close up against the tube, which makes it still pretty economical. 03-Feb-20 04:36 PM oh, i thought OpenMC was just neutral particle transport for fission shenanigans 03-Feb-20 04:36 PM i'll have to check it out! 03-Feb-20 04:36 PM (but, yes, also could just do this manually. i just need simple example problems to motivate myself to learn these tools) 03-Feb-20 04:37 PM <__ice9#6039> @qualia what size cap bank did your DPF plans involve? Was just discussing these with @Mason_Yu earlier above but it seemed very difficult to get neutron production comparable to ordinary RF sources without huge economies of scale due to an I^3.8 or so scaling rule. 03-Feb-20 04:37 PM 1.6kJ, 25kV 03-Feb-20 04:38 PM OpenMC does photons as well! If you don't need a phantom and the simulation is easy 03-Feb-20 04:39 PM unfortunately my caps are somewhat high-inductance for this application (<100nH) and also the Aerovox SX series may not be appropriate for very many 160kA discharges 03-Feb-20 04:39 PM Introduction to Health Physics by Johnson and Cember is really good with lots of examples and practical problems 03-Feb-20 04:39 PM Do you expect 160kA peak current from your bank? That's really quite high 03-Feb-20 04:40 PM <__ice9#6039> Some of the Chinese ZVS induction heaters are actually quite unreliable-- can fail to start oscillating and then very rapidly blow a FET. For my 15kW one, I am just directly driving a full bridge of large IGBT bricks. 03-Feb-20 04:40 PM The neutron yield scaling starts becoming favourable at the scale of a small cart (i.e somewhere about 100 kA peak current and 10 kJ of energy) 03-Feb-20 04:40 PM That will give you >10^9 neutrons per shot if properly designed 03-Feb-20 04:42 PM that was more of an upper bound 03-Feb-20 04:42 PM https://twitter.com/profanegeometry/status/1162612268472754176 my late-night attempt at design parameter calculations are here 03-Feb-20 04:42 PM <__ice9#6039> Ah yeah it looks like he directly drives the FET arrays in this induction heater as well 03-Feb-20 04:43 PM in practice i'm sure the stripline and dynamic inductance of the device itself would make those numbers quite a bit lower 03-Feb-20 04:44 PM Oh, I think you need to take into account energy transfer into the plasma during the rundown (plus resistivity during the collapse), it's going to be lower than the "drop a wrench across the terminals" peak current 03-Feb-20 04:44 PM @__ice9 @Spirit Are there other widely available getter materials? Will titanium work or something like that? 03-Feb-20 04:44 PM I see you used the RGV model, it does model the dynamics quite well and will give you an optimization based on energy transfer and rundown timing 03-Feb-20 04:45 PM and the SX series are 'Light Duty', so they may not tolerate that kind of abuse anyways. they were originally used in a pulsed RF accelerator system and seem like they're meant to be resonant energy storage more than explosive instantaneous discharge 03-Feb-20 04:46 PM @ZeptoBars barium is a common getter 03-Feb-20 04:46 PM But it also makes some key assumptions, namely the snowplow model's infinitely thin sheathe, that cannot be applied at all phases/integration regimes. This is due to the diffusive nature of the sheathe when it first forms and the necessity to have high enough accleration to form a dense enough sheathe 03-Feb-20 04:46 PM The Lee model doesn't do this either 03-Feb-20 04:47 PM interesting 03-Feb-20 04:47 PM i haven't been able to sit down with the Spooky Lee Model Spreadsheet long enough to get anything out of it 03-Feb-20 04:47 PM There is also the inductance and resistance of the switch 03-Feb-20 04:47 PM that one polish RGV solver was buggy as heck for me 03-Feb-20 04:47 PM My professor freaking laughed at me when I showed him that spreadsheet lol, but it works 03-Feb-20 04:47 PM it's awe inspiring 03-Feb-20 04:47 PM Up to a point 03-Feb-20 04:47 PM I also got the newer stuff from Sing Lee himself, including radiative collapse corrections for argon and neon pinches and also dual bank configurations 03-Feb-20 04:48 PM kinda want to mail the polish folks and ask for the fortran they used to make it, like let me just compile it on linux how hard can it be 03-Feb-20 04:48 PM ooh, dual bank? as in multiple discharges? 03-Feb-20 04:48 PM or like crowbaring the ringing into a second bank? 03-Feb-20 04:49 PM You guys are scary. Please don't nuke the city 03-Feb-20 04:49 PM curtsies ablatively 03-Feb-20 04:49 PM Switching a fast bank in with a second switch at the onset of radial compression/collapse 03-Feb-20 04:50 PM ooh interesting 03-Feb-20 04:50 PM So the goal is to increase peak current without losing compression as far as I understand it 03-Feb-20 04:51 PM the switches i got with the caps are some slow (but custom!) CX1536 deuterium thyratrons, probably not great for this application. they basically need grid preionization to get to their datasheet-rated risetime 03-Feb-20 04:51 PM 1356? 03-Feb-20 04:51 PM idr 03-Feb-20 04:51 PM Hey I've got the same ones! 03-Feb-20 04:51 PM But for triggering only 03-Feb-20 04:51 PM whoa hey neat :D 03-Feb-20 04:52 PM Not large enough for my bank I'm afraid 03-Feb-20 04:52 PM yeah i bet they'd do great for that 03-Feb-20 04:52 PM <__ice9#6039> @ZeptoBars titanium is decent but only when it is hot. Barium is much better at ambient room temp. I just built an argon gas thermal scrubber based on a fluidized bed reactor running ferrotitanium sand at 850C to purify the intake gas for my graphite furnace. But that wouldn't work at room temp. 03-Feb-20 04:53 PM you can also buy brand new getters 03-Feb-20 04:53 PM https://www.saesgetters.com/products-functions/products/getters/non-evaporable-getters/coated-strips 03-Feb-20 04:53 PM and these 03-Feb-20 04:53 PM https://www.saesgetters.com/products-functions/products/getters/evaporable-getters 03-Feb-20 04:53 PM the former is what Dalibor, ArNeo(Neonixie/YunaDigick), and Millclock use. 03-Feb-20 04:56 PM I've been working on a PIC code from the 90s to simulate the DPF final pinch, and after 3 months of struggle on a puny little laptop I'm afraid I will have to move to ideal MHD codes 03-Feb-20 04:57 PM rip 03-Feb-20 04:57 PM I'm no good with Fortran but most of these codes require you to write custom input decks and know the math inside and out 03-Feb-20 04:57 PM I .. almost want to try and learn modern fortran 03-Feb-20 04:57 PM the reason you're struggling is because you're using fortran 03-Feb-20 04:58 PM <__ice9#6039> @Spirit yeah their non-evaporable getters appear to be using zirconium alloy instead, but it's similar 03-Feb-20 04:58 PM mhm 03-Feb-20 04:59 PM The source code's written in Fortran! I for one can appreciate the fact that OpenMC is completely ditching Fortran to move to C++ 03-Feb-20 04:59 PM which seems like saying 'I want to learn modern C' where the first step is seemingly almost always 'learn all the old awful ways first, suffer greatly, then use the new niceness once you won't be lost in ancient codebases' 03-Feb-20 04:59 PM same for C++ 03-Feb-20 05:00 PM <__ice9#6039> Hmm yes 03-Feb-20 05:00 PM <__ice9#6039> Then when you do performance engineering, you get to go right back to the older and less safe techniques to get closer to the metal 03-Feb-20 05:05 PM i have the annoying problem that i can set up compute platforms all day long -- i had a single-system-image beowulf cluster of my own in high school -- but i can't actually program my way out of a wet paper bag to take advantage of it 03-Feb-20 05:06 PM <__ice9#6039> Cluster software development imo is all about finding frameworks that you actually like and then just using them to handle the task pools and message passing and so on 03-Feb-20 05:07 PM i guess it is also the whole 'knowing the math' thing 03-Feb-20 05:08 PM <__ice9#6039> For fancy low latency stuff local to the machine, message passing between busy-waiting core-affinity-locked threads or processes using ringbuffers is where it's at. That and a lot of cache prefetching, precomputing stuff, etc. 03-Feb-20 05:08 PM <__ice9#6039> Meanwhile shared reference state with only a single authorized writer acting atomically (if necessary, with locks and busy-waiting blocking reads by the clients) works fine and is fast 03-Feb-20 05:08 PM <__ice9#6039> Lol idk this is all off topic >___> 03-Feb-20 05:11 PM So It Goes 03-Feb-20 05:11 PM this server is bad for my focus at work 03-Feb-20 05:11 PM guess i'll play with OpenMC on the commute back home 03-Feb-20 05:16 PM <__ice9#6039> http://lampes-et-tubes.info/xr/xr023.php?l=e Flash x-ray tube construction details 03-Feb-20 05:16 PM <__ice9#6039> Appears to be essentially just a TIG welding electrode and a circular metal plate 03-Feb-20 05:20 PM I get that... Discord can be quite the distraction, its sometimes nice to take a few day break from the "internet" 03-Feb-20 05:20 PM J.C. Martin's tome on pulsed power (predominantly for flash radiography) talked about making flash x-ray tubes out of literal garbage 03-Feb-20 05:20 PM spoons and forks and random bits of string and hair 03-Feb-20 05:20 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_2020-02-03-17-23-112-21EE0.png 03-Feb-20 05:20 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_2020-02-03-17-23-342-B3D10.png 03-Feb-20 05:25 PM ah yes the good old standard fork and spoon 03-Feb-20 05:30 PM <__ice9#6039> Amazing, plastic x-ray tubes pumped with backing pumps 03-Feb-20 05:30 PM <__ice9#6039> Lol @ all the horrible damage to the inside of the tube from these massive pulses 03-Feb-20 05:38 PM @__ice9 they have a page about the russian pulse xray tubes as well: http://lampes-et-tubes.info/xr/xr120.php?l=e and http://lampes-et-tubes.info/xr/xr042.php?l=e 03-Feb-20 05:38 PM pretty simple geometries 03-Feb-20 05:43 PM <__ice9#6039> 30kV x 3nF film caps are 1.35J each x 10 = 13.5J @ 300kV, pretty comparable to pic related 03-Feb-20 05:43 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200203-194220-A71B5.png 03-Feb-20 05:45 PM 100R in 3ns 03-Feb-20 05:45 PM pretty much instant lethality 03-Feb-20 05:45 PM please don't dead 03-Feb-20 05:47 PM <__ice9#6039> The HV PSU to run these is also, I might note, quite instantly lethal. 03-Feb-20 05:47 PM <__ice9#6039> And for that matter, so is even its charging circuit 03-Feb-20 05:48 PM honestly...make sure you double and triple check your math with the voltages you are talking about running things 03-Feb-20 05:48 PM The issue with x-rays is that it's not too instant 03-Feb-20 05:48 PM the higher the energy xrays the more penetrating they are as far as i understand too? 03-Feb-20 05:48 PM You hear "pop" and your mind slowly fills with dread 03-Feb-20 05:48 PM <__ice9#6039> Hmm I have routinely run high powered high voltage supplies. 03-Feb-20 05:48 PM <__ice9#6039> Well yeah if you were running the thing while in front of it ffs 03-Feb-20 05:48 PM <__ice9#6039> The trouble with HV cap supplies is that they can still kill you while they are turned off and while you are preparing to modify/repair them. So I always use bleed resistors etc. Even so, you are usually nearby while using them. An x-ray device is not generally used while standing next to it. I use remotely triggered switches for this stuff, same as lasers. 03-Feb-20 05:48 PM <__ice9#6039> Still, this is the kind of system for which a proper interlock is merited. 03-Feb-20 05:52 PM at least 03-Feb-20 05:52 PM i wanted to design some kind of gravity-assist shorting switches for my capacitor bank, so i could put a short across them if needed from a safe distance 03-Feb-20 05:52 PM also had considered building the whole thing into an EMI shielding cage 03-Feb-20 05:53 PM <__ice9#6039> Why a short and not a resistor? 03-Feb-20 05:53 PM already have resistors, but would like shorts as well 03-Feb-20 05:53 PM <__ice9#6039> Hmm what's the use case? 03-Feb-20 05:53 PM something something defense in depth 03-Feb-20 05:53 PM it's the same caps that were vaguely meant for the plasma focus 03-Feb-20 05:54 PM <__ice9#6039> Yeah they would survive it fine, but the shorting object would vaporize 03-Feb-20 05:54 PM <__ice9#6039> 50-100J will explode a wire easily enough 03-Feb-20 05:54 PM <__ice9#6039> 1.3kJ will explode a wrench 03-Feb-20 05:54 PM <__ice9#6039> Although, probably not a thick copper bar 03-Feb-20 05:55 PM yeah 03-Feb-20 05:55 PM granted i guess they don't need to be zero-ohm shorts 03-Feb-20 05:55 PM just, a second safing mechanism in the event the bleed resistors kick the bucket for any reason 03-Feb-20 05:56 PM <__ice9#6039> Heh no such thing 03-Feb-20 05:56 PM well yeah 03-Feb-20 05:56 PM ykwim 03-Feb-20 05:56 PM <__ice9#6039> 0.001 ohm is quite happy to throw many many kW Joule heating given enough current 03-Feb-20 05:56 PM <__ice9#6039> 1kA = 1kW @ 1mΩ 03-Feb-20 05:56 PM <__ice9#6039> This is annoying for induction heaters as you can well imagine, because of the skin effect 03-Feb-20 05:56 PM <__ice9#6039> It's common to lose 10-20% of total power into resistive heating of the coil itself and its cooling water 03-Feb-20 05:59 PM are they amenable to litz wire work coils? 03-Feb-20 05:59 PM ah, but cooling fluid, hm 03-Feb-20 05:59 PM <__ice9#6039> Maybe if you keep them in the water inside the tube 03-Feb-20 05:59 PM <__ice9#6039> That's actually a very interesting idea 03-Feb-20 05:59 PM <__ice9#6039> Without the water, no, because the load would melt them 03-Feb-20 06:01 PM @__ice9 I was not really saying to be careful with the HV side of things and more the penetrating power of pulsed xrays in the >150kV realm being discussed. 03-Feb-20 06:01 PM <__ice9#6039> I may try to thread some back and forth through the coil and along the exterior of the RF output rails, though for the latter I was actually thinking more like fins/plates along the tubing 03-Feb-20 06:01 PM <__ice9#6039> Yes I know that. My point was that 300kV @ 13.5J is instantly lethal in its own right. 03-Feb-20 06:01 PM <__ice9#6039> But don't even get me started on talking about lathes 03-Feb-20 06:02 PM honestly surprising how so few joules suffice 03-Feb-20 06:02 PM i guess the electron bremsstrahlung conversion efficiency is pretty high 03-Feb-20 06:02 PM less so when trying to fling ions around 03-Feb-20 06:02 PM s'where my head's been at 03-Feb-20 06:03 PM <__ice9#6039> I had been somewhat mystified earlier as to whether there was any way to improve x-ray efficiency. Ordinary tubes are consistently only about 0.1-1% efficient. 03-Feb-20 06:03 PM <__ice9#6039> But these are much more so 03-Feb-20 06:03 PM <__ice9#6039> So here is one possible (?) answer 03-Feb-20 06:03 PM <__ice9#6039> Huh wow Marx generators can run at e.g. 50-500Hz 03-Feb-20 06:03 PM <__ice9#6039> Yeah I see the issue there 03-Feb-20 06:03 PM <__ice9#6039> I saw a paper using ordinary x-ray tubes to do it a while ago, but it took an unreasonably long time 03-Feb-20 06:03 PM <__ice9#6039> Might have some interesting applications in chemistry as well, but usually UV is more common and a lot safer 03-Feb-20 06:03 PM <__ice9#6039> Another obvious implication is that imaging will need an unusually thick lead sheet backdrop. The potential for x-ray reflections should also be examined, to determine whether full enclosure of a closed region encompassing the target is likely to be necessary 03-Feb-20 06:15 PM this isn't helping my 'clearly if i lived in the middle of death valley then i'd have tons of space to do stupid experiments' fantasies 03-Feb-20 06:15 PM i would absolutely consider this kind of thing cause for full enclosure 03-Feb-20 06:16 PM enclosure + healthy distance from any neighbors 03-Feb-20 06:16 PM <__ice9#6039> Interesting-- some papers seem to be claiming that efficiency is not actually higher than for ordinary tubes 03-Feb-20 06:21 PM yeah i don't know how they'd be more efficient exactly 03-Feb-20 06:21 PM just brute force 03-Feb-20 06:21 PM okay time to go home and put kilovolts on a laser vibrates excitedly 03-Feb-20 06:21 PM kbye 03-Feb-20 06:24 PM <__ice9#6039> Haha bye glhf 03-Feb-20 07:17 PM <__ice9#6039> It appears that annular thin tungsten foil cathodes are often used in the higher-voltage Russian flash tubes, called 'blade cathodes'. This avoids blocking the window with tungsten. 03-Feb-20 07:17 PM <__ice9#6039> Z-pinch events in some noble gases can produce up to 10% x-ray efficiency, albeit mostly at e.g. 1-2keV https://aip.scitation.org/doi/10.1063/1.334734 03-Feb-20 07:17 PM <__ice9#6039> @ZeptoBars more on directionality 03-Feb-20 07:17 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200203-212511-7B239.png 03-Feb-20 07:17 PM <__ice9#6039> This is actually kind of inconvenient for high-voltage designs, as the direction of the electron beam is straight into the usually-tungsten anode 03-Feb-20 07:35 PM that pattern is interesting 03-Feb-20 07:35 PM <__ice9#6039> Some efficiency improvement notes, but this is balanced to some degree by the greater directional losses into the anode 03-Feb-20 07:35 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200203-213439-8BF61.png 03-Feb-20 07:35 PM <__ice9#6039> Though it does make me wonder about a uranium anode 03-Feb-20 07:35 PM makes sense though that as you go to higher energies the emission would be more narrow 03-Feb-20 07:36 PM <__ice9#6039> Thorium would be way better, much higher melting point 03-Feb-20 07:44 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200203-214327-8966A.png 03-Feb-20 07:44 PM <__ice9#6039> Of course both thorium and uranium tarnish quite badly in air, and their oxides are extremely refractory, so processing would be much more difficult than tungsten for only a 21% efficiency gain for Th 03-Feb-20 08:21 PM <__ice9#6039> ... I guess as one practical implication, this seems to imply that old tubes with bad filaments could be repurposed for flash x-ray use on an inexpensive Marx generator instead 03-Feb-20 09:21 PM <__ice9#6039> Tangentially, rotating anode x-ray tubes are conventionally driven by a set of motor windings, but these are often absent in listings for bare tubes. A spinning coaxial magnet mounted on a motor would probably be an adequate substitute. 03-Feb-20 09:21 PM <__ice9#6039> There are also many listings for shielded CT tubes which usually do include the driving coils, though they are generally more costly. These are liquid-cooled units capable of dissipating in some cases well over 100kW. 03-Feb-20 09:21 PM <__ice9#6039> Here is how they are used: https://www.youtube.com/watch?v=TWU-nB4l5dU 03-Feb-20 09:31 PM 100kW seems a bit nuts 03-Feb-20 09:31 PM highest I've seen is maybe around 10 03-Feb-20 09:31 PM you don't want to kill your patients, merely almost-but-not-quite overdose them for a single scan 03-Feb-20 09:31 PM but CTs are scary complex, probably more complex than MRI, at least physically 03-Feb-20 09:31 PM (MRI is mostly math and RF voodoo) 03-Feb-20 09:46 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F04AD.png 03-Feb-20 09:46 PM this is impressively complicated 03-Feb-20 09:46 PM helium purge, copper TAPE anode, "debris" collection 03-Feb-20 09:48 PM <__ice9#6039> CT scans impose a rather large radiation dose compared to pretty much anything except radiation therapy for cancers 03-Feb-20 09:48 PM yeah, because you spend several minutes under a hot beam 03-Feb-20 09:48 PM <__ice9#6039> Laser wakefield acceleration looks interesting for neutron sources 03-Feb-20 09:48 PM <__ice9#6039> Yep 03-Feb-20 09:53 PM Here is one paper on the chromium photocathode stuffs https://aip.scitation.org/doi/abs/10.1063/1.4962147 03-Feb-20 09:53 PM probably not in the range of power you're interested in but fascinating nonetheless 03-Feb-20 09:54 PM I wonder if a photo-xray-thing hybrid could be made 03-Feb-20 09:54 PM electrons emitted, without collimation, slam directly into the transmissive target 03-Feb-20 09:54 PM <__ice9#6039> >femtosecond pulses in the near ultraviolet (257 nm)  Fair bit harder to make than a piece of tungsten wire tbf 03-Feb-20 09:54 PM lol yeah 03-Feb-20 09:54 PM yes indeed 03-Feb-20 09:54 PM just sayin', though.. there are various elements suitable for photocathodes and pushing some electrons through a gold film that protects said element from atmosphere is proven 03-Feb-20 09:55 PM the issue is getting it there in the first place 03-Feb-20 09:56 PM getting what there? the films? 03-Feb-20 09:56 PM yeah the photocathode, into the tube 03-Feb-20 09:56 PM not an issue for production(PMTs, etc), but an issue for DIY 03-Feb-20 09:57 PM are you talking about deposition of the films on the fiber or other substrate, or the physical process of placing the cathode into a glass tube? 03-Feb-20 09:58 PM both, and the process for transporting it 03-Feb-20 09:59 PM you're not dealing with anything much larger, at all, than an optical fiber, interesting concern for me would be the sealing of a glass fiber through a molten glass shell 03-Feb-20 09:59 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580795923397-EDD91.png 03-Feb-20 09:59 PM how are neutrons imaged? 03-Feb-20 09:59 PM film? 03-Feb-20 09:59 PM @Metanoic metal to glass to epoxy seal 03-Feb-20 10:00 PM <__ice9#6039> Scintillation iirc 03-Feb-20 10:00 PM yea I was just thinking you'd probably get pretty far coating the fiber cladding in a metal 03-Feb-20 10:01 PM <__ice9#6039> Gadolinium thin layer 03-Feb-20 10:01 PM still would need to be careful to not heat things up too much and screw with the fiber's axial geometry.. 03-Feb-20 10:01 PM when I fiiiinally get all my stuff together/in order I'm tackling a somewhat similar process of coating the tip of a fiber in black phosphorus and other such goodies 03-Feb-20 10:01 PM not for emission though, just going to r&d on semiconductor saturable absorbers for passive mode locking of femtosecond fiber lasers 03-Feb-20 10:04 PM <__ice9#6039> https://en.wikipedia.org/wiki/Neutron_imaging 03-Feb-20 10:04 PM you think that frog survived? 03-Feb-20 10:04 PM <__ice9#6039> Has descriptions of other recording methods 03-Feb-20 10:04 PM <__ice9#6039> I assume it was already dead lol 03-Feb-20 10:05 PM pose looks pretty dead 03-Feb-20 10:05 PM hehehehe 03-Feb-20 10:05 PM <__ice9#6039> Not usually used on biological materials 03-Feb-20 10:05 PM any time I see a frog used in science I think of the one from the national high magnetic field lab here in FL where it's floating, alive, inside a super powerful electromagnet 03-Feb-20 10:06 PM probably also very unhappy 03-Feb-20 10:06 PM nah he was totally groovin' 03-Feb-20 11:20 PM <__ice9#6039> Aha. Finally found the doubly-nested coaxial neutron generator reference discussion again. https://ipo.lbl.gov/lbnl1764/ 03-Feb-20 11:20 PM <__ice9#6039> This is all Leung's group 03-Feb-20 11:20 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1580800893036-68D82.png 03-Feb-20 11:20 PM <__ice9#6039> Very high figures without needing a gymnasium full of capacitors 03-Feb-20 11:31 PM <__ice9#6039> Makes me wonder what has happened since then, though. Not many updates apparent. https://nuc.berkeley.edu/people/ka-ngo-leung/ 03-Feb-20 11:59 PM probably something he is not allowed to publish about if one year he was winning awards and the next he is not publishing at all 03-Feb-20 11:59 PM or maybe he is working on something really big...? who knows 03-Feb-20 11:59 PM (or maybe he retired?) 04-Feb-20 12:28 AM <__ice9#6039> I'm getting the sense that emphasis may have shifted more toward commercial involvements, but not sure 04-Feb-20 12:28 AM <__ice9#6039> Also seems to have done a lot with semiconductor fab tech 04-Feb-20 12:28 AM <__ice9#6039> Anyway it appears that producing enough neutron flux for imaging requires power levels that are relatively impractical when considering the costs of the components. 04-Feb-20 12:42 AM <__ice9#6039> I strongly suspect that it would be possible to use old sketchy tubes (bad filaments, a bit gassy, slightly sputtered, etc.) for flash x-ray instead, likely at higher than typical voltages. The original flash x-ray papers seem to allude to much more lax operating conditions, and it is a cold cathode phenomenon by explosive emission. 04-Feb-20 12:42 AM <__ice9#6039> However, anode heating will still impose limits. 04-Feb-20 10:24 AM <__ice9#6039> The critical angle for total external x-ray reflectivity is usually under about 2° 04-Feb-20 10:24 AM <__ice9#6039> http://gisaxs.com/index.php/Critical_angle 04-Feb-20 10:39 AM <__ice9#6039> Compton scattering is therefore more relevant from a directional shielding standpoint 04-Feb-20 10:39 AM <__ice9#6039> Rayleigh scattering tends to be directed through the object for hard x-rays 04-Feb-20 10:39 AM <__ice9#6039> The backscatter is largely Compton 04-Feb-20 10:39 AM <__ice9#6039> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4487281/ 04-Feb-20 10:58 AM <__ice9#6039> Backscatter dose for a tube running at 80kVp is supposedly about 0.15% at the approximate position of the x-ray tube, although placing a few layers of steel mesh in front of the main shielding apparently catches much of the backscatter-- which is comprised of lower-energy photons. That also implies that further shielding on the reverse path could be made from lighter materials. Barium sulfate paint over ordinary gypsum or similar materials seems to be mentioned fairly often. 04-Feb-20 10:58 AM <__ice9#6039> Given no particular need to keep the barium paint on the gypsum itself rather than separated from it, it would appear that barium sulfate paint on a screen followed by a few walls made of gypsum would be equivalent 04-Feb-20 10:58 AM <__ice9#6039> So the conclusion is to place a few sheets of steel mesh over the rear shielding surface and another few of them laminated with barium sulfate behind the imaging setup. 04-Feb-20 10:58 AM <__ice9#6039> And to measure. 04-Feb-20 10:58 AM <__ice9#6039> For higher tube kVp as in pulsed tubes, the Compton scattered photons will be of broadly higher energy, so a rear lead sheet is still advisable. 04-Feb-20 10:58 AM <__ice9#6039> Hope this is helpful to others interested in the subject. 04-Feb-20 12:14 PM <__ice9#6039> That reminds me: it is best to be cautious around tubes with beryllium windows especially-- the kind mainly for doing XRF etc. 04-Feb-20 12:14 PM <__ice9#6039> They lack the regulatorily-mandated inherent filtration provided by an aluminum plate in medical/dental systems to screen out soft x-rays, which pose a more significant radiation hazard due to their greater and more locally concentrated absorption profile 04-Feb-20 12:14 PM <__ice9#6039> Also useful to recall that leaded glass is an effective shielding material, though it needs to be proportionately thicker than pure lead. 04-Feb-20 12:14 PM <__ice9#6039> Sheets of it are a bit costly for some reason. It can be obtained in the same litharge proportion as the shielding type by just melting down old unwanted lead crystal glassware. I'm not really sure how to make it into float glass without it clinging to the crucible walls, though graphite would likely work. 04-Feb-20 12:32 PM <__ice9#6039> Nice paper on flash x-ray tube geometry studies for an unusual carbon fibrous cathode 04-Feb-20 12:32 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/steyer1990-68EAD.pdf 04-Feb-20 12:32 PM <__ice9#6039> Strong magnets can be used to increase x-ray emission efficiency, but it's useless for imaging because they mostly don't end up at the focal spot. 04-Feb-20 12:32 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200204-143612-DDCA6.png 04-Feb-20 04:53 PM Continuing discussion about photocathodes: I see that free electrons lasers use different exotic cathode materials with alkali metals, which are hard to manufacture and are dead in air. I also see that metal cathodes still work with low efficiency. Is there any data or references on air-stable photocathode materials, which does not require illumination shorter than 355nm? 532nm sensitivity would be even nicer. 04-Feb-20 04:53 PM Heh, that was my question 04-Feb-20 05:26 PM This isn't super close but still driveable https://raleigh.craigslist.org/spo/d/raleigh-radiation-detection-instrument/7068149860.html 04-Feb-20 05:26 PM Would that have anything over what I just got? 04-Feb-20 05:27 PM what'd you just get? 04-Feb-20 05:28 PM https://www.ebay.com/itm/Dosimeter-Model-3100-Survey-Meter-with-Bicron-GI-LE-Probe/323743224389?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 04-Feb-20 05:29 PM so the bicron scintillator's gonna be more sensitive for gammas, maybe beta.. that frisker probe looks a lot like a 44-9, which is alpha/beta/gamma sensitive. but idk what that probe actually is, so can't say for sure 04-Feb-20 05:29 PM That bicron scint is a low energy optimized probe 04-Feb-20 05:29 PM The Inspector is really basic 04-Feb-20 05:29 PM But for $100 that probe is nice 04-Feb-20 05:30 PM but is it worth $100 + 5 hour round trip 04-Feb-20 05:30 PM @qualia the bicron is a G1LE, the inspector is a 44-9ish 04-Feb-20 05:30 PM if you're gonna start an Instrument Collection you might as well get the spiraling-out-of-control-ness out of the way early 04-Feb-20 05:30 PM ah ok 04-Feb-20 05:30 PM yeah idk for $100 if i didn't already have a ludlum 3 + 44-9 i'd consider that worthwhile 04-Feb-20 05:30 PM but i also like roadtrips, so 04-Feb-20 05:31 PM Data on the inspector https://ndtsupply.com/se-inspector-exp-1.html 04-Feb-20 05:32 PM the 'built in efficiencies' is intriguing 04-Feb-20 05:32 PM if it has builtin adjustable energy calibration curves that's actually really neat 04-Feb-20 05:32 PM maybe not incredibly useful depending on your needs, but cool nonetheless 04-Feb-20 05:34 PM Seems like it'll likely not really be worth it in the end, I don't need more redundant equipment 04-Feb-20 05:34 PM Also IIRC this is the good general use CDV right? https://boulder.craigslist.org/clt/d/boulder-geiger-counter-cdv-700-model-6b/7069003285.html 04-Feb-20 05:34 PM not the one of the ones with the "if the meter reads anything you're already dead"? 04-Feb-20 05:38 PM looks like it 04-Feb-20 05:38 PM at least, general use in the 'it does beta and gamma' sense 04-Feb-20 05:38 PM yeah 05-Feb-20 10:52 AM The 700 is the one I always referred to as the "specialist", as in who you issue it too when you leave the fallout shelter to see what you can rebuild civilization with. The other two models are basically security blankets to make the privates and corporals feel like they're doing something productive while they march in the death cloud. 06-Feb-20 05:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200206_114507-8CD91.jpg 06-Feb-20 05:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200206_114520-BFFAB.jpg 06-Feb-20 05:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200206_114542-FD854.jpg 06-Feb-20 05:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200206_142356-E9609.jpg 06-Feb-20 06:40 AM neattt 06-Feb-20 10:52 AM nice unit :o 06-Feb-20 11:07 AM thanks :3 06-Feb-20 11:12 AM Love those old tek scopes with the monochrome CRT and color LCD over top to do the color 06-Feb-20 11:12 AM oh yes 06-Feb-20 11:12 AM would not want to miss that 06-Feb-20 11:12 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D0AA0.png 06-Feb-20 11:12 AM well that doesn't seem right 06-Feb-20 11:12 AM (ignore the energy scale, it's not calibrated 06-Feb-20 11:12 AM that should be one Am peak 06-Feb-20 11:12 AM and I don't think that that's summing 06-Feb-20 11:12 AM as they have the same ratio regardless of distance to the detector 06-Feb-20 11:32 AM huh. is that like a thin Be window over the crystal? 06-Feb-20 11:32 AM its not from something further down the decay chain, is it? 06-Feb-20 11:34 AM it's Be, yep 06-Feb-20 11:34 AM hm, decay chain would make sense, but I've never seen a spectrum like this from a smoke detector 06-Feb-20 11:34 AM more experimenting tomorrow, at the moment I need that power supply for something else 06-Feb-20 11:34 AM something potentially more exciting 06-Feb-20 11:34 AM https://www.youtube.com/watch?v=dFTmKOGTbrQ 06-Feb-20 11:43 AM if it is a Be window + Am241 dont you get some extra gamma and neutrons out of that? 06-Feb-20 11:43 AM not at that activity 06-Feb-20 02:11 PM winces As someone who spent 9 weeks worth of evenings cleaning up an instrument calibration shop due to Be shed from thin window detectors, I am never happy to see them uncovered. The fact that the same room got heavily tritium contaminated two weeks after I finished just added insult to injury. 06-Feb-20 02:12 PM I have a cracked Be window mixed with oil @funranium 06-Feb-20 02:12 PM surely you need it uncovered to measure things with it 06-Feb-20 02:12 PM I think I threw away most of it 06-Feb-20 02:12 PM But the window is still sitting wrapped up in tape 06-Feb-20 02:12 PM not to downplay your suffering, ofc 06-Feb-20 02:13 PM this is my first Be window detector, I'm happy to learn new safety practices @funranium 06-Feb-20 02:13 PM is it a Be window? 06-Feb-20 02:13 PM or an Al? 06-Feb-20 02:13 PM it looks more like Al 06-Feb-20 02:13 PM my G1LE has a similar looking shiny window and I'm pretty sure it's Al 06-Feb-20 02:14 PM looks like Be to me 06-Feb-20 02:14 PM the Be windows I have are all rough-looking 06-Feb-20 02:14 PM like 2000 or 4000 grit sandpaper 06-Feb-20 02:14 PM nah, I've done a lick test and it definitely doesn't taste like al 06-Feb-20 02:14 PM huh, weird 06-Feb-20 02:14 PM >.> 06-Feb-20 02:14 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC02647-1B966.JPG 06-Feb-20 02:14 PM well then your Be Windows are heavly degraded 06-Feb-20 02:14 PM Here's Be 06-Feb-20 02:14 PM untouched, NIB 06-Feb-20 02:14 PM let me get a pic of my Al window 06-Feb-20 02:17 PM it's Be for sure 06-Feb-20 02:17 PM it looks like all the Be windows I've seen so far 06-Feb-20 02:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200207_011725-4FCD4.jpg 06-Feb-20 02:17 PM here's my g1le 06-Feb-20 02:18 PM seems shinier and lighter 06-Feb-20 02:18 PM yeah I think it's al 06-Feb-20 02:18 PM yeah, Be is pretty dark, almost brown 06-Feb-20 02:18 PM I just got a bad cam on my phone 06-Feb-20 02:19 PM @funranium was it shed oxide from corroded windows, or just plain old elemental Be flaking? 06-Feb-20 02:37 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_2952-1353B.JPG 06-Feb-20 02:38 PM DPM/100cm^2? 06-Feb-20 02:38 PM huh? 06-Feb-20 02:38 PM Yea its a new one to me too, it is a thing that exists though 06-Feb-20 02:38 PM its like dosage per minute/100cm^2 or some weird thing 06-Feb-20 02:38 PM but yea the decent into Geiger counters begins thanks to @GigaSquirrel :) 06-Feb-20 02:43 PM Well, you have a 44-9 06-Feb-20 02:43 PM Great generic hot-or-not probe to always have 06-Feb-20 02:51 PM yea I think its intact 06-Feb-20 02:51 PM decays per minute 06-Feb-20 02:51 PM it looks a tad bit rough though 06-Feb-20 02:51 PM which is somehow different from CPM 06-Feb-20 02:51 PM think one's incident on a detector and the other's actually what the source is doing 06-Feb-20 02:52 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_2953-993FD.JPG 06-Feb-20 02:53 PM lgtm :D 06-Feb-20 02:53 PM so the little black mark to the top left is wear on the window? it looks like? like something chipped off somehow without breaking that thing... 06-Feb-20 02:53 PM otherwise just the mesh is a little dented 06-Feb-20 02:55 PM power it on 06-Feb-20 02:55 PM if it starts arcing, it's dead :P 06-Feb-20 02:55 PM this all reminds me i need to get more rechargeable D batteries 06-Feb-20 02:55 PM so expensive 06-Feb-20 02:55 PM .. that, or 3d print a battery-replacement shim 06-Feb-20 02:59 PM I didn't check the model 3 before hooking the probe up because it came with it and I assumed it was set for it... But since I don't know where the model 12 came from I have to adjust the HV on it to whatever this is and also calibrate it to the probe would I not? 06-Feb-20 03:08 PM for now, just dialing the voltage in to 900V should suffice 06-Feb-20 03:08 PM i wouldn't touch any of the other calibration controls yet 06-Feb-20 03:08 PM i think the 12 has an adjustable discriminator, too? can't remember 06-Feb-20 03:13 PM <__ice9#6039> @funranium "shed"? They "shed"? Could you describe more about this process and any viable preventative measures? Are there any e.g. polymer thin film coatings that could be applied to something like this (negligible resulting filtration) to maintain window surface integrity? 06-Feb-20 03:15 PM yeah, if there's some kind of grave under-general-use contamination risk with these things we oughta disseminate that info asap 06-Feb-20 03:15 PM i surely don't want to have to deal with anything of the sort if at all possible and i suspect many others (at least, those of us not cutting sheets of it in bandsaws under WD-40.....) would also care to not have to do so 06-Feb-20 03:17 PM <__ice9#6039> I was just thinking maybe an oil layer also if that oxide layer is actually frangible 06-Feb-20 03:17 PM <__ice9#6039> x-rays basically don't care about tiny layers of hydrocarbons 06-Feb-20 03:18 PM everything i've read suggests 'don't use any kinds of fluids on these windows', though that seems to be from a cleaning perspective 06-Feb-20 03:18 PM vacuum systems might tho 06-Feb-20 03:32 PM ehh I need a meter that can do at-least 1gigohm 06-Feb-20 03:32 PM <__ice9#6039> I just did a quick literature survey and am definitely not seeing this under ordinary stationary room temperature conditions without direct handling. Excerpts forthcoming. Heating beyond 600-700C, welding, or hot forming can all create oxide spall though. 06-Feb-20 03:46 PM <__ice9#6039> Found this so far 06-Feb-20 03:46 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-172707-89447.png 06-Feb-20 03:46 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-172900-ED525.png 06-Feb-20 03:46 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-173059-C2A96.png 06-Feb-20 03:46 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-173105-A5F32.png 06-Feb-20 03:46 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-173114-6AEC8.png 06-Feb-20 03:46 PM <__ice9#6039> @funranium could you describe more about this "shed" beryllium or BeO that you mentioned? Was it from brittle deformation/fragmentation of those thin film windows? 06-Feb-20 03:51 PM keep forgetting beryllium is an alkaline metal 06-Feb-20 03:51 PM i was under the impression that elemental Be was just fine in atmosphere, but it looks like, from that last document, it does actually form a protective BeO layer in oxygen 06-Feb-20 03:51 PM like aluminum i guess 06-Feb-20 03:51 PM wonder if it combusts if abraded underwater 06-Feb-20 03:51 PM (i will not be testing this) 06-Feb-20 03:51 PM Beryllium (Be) is the only alkaline earth metal that does not react with water or steam, even if metal is heated to red heat. #wikifinds 06-Feb-20 03:57 PM <__ice9#6039> Given some humidity, it will form a supposedly-very-stable aluminum-like protective oxide coating at room temperature, albeit very thin 06-Feb-20 03:57 PM <__ice9#6039> At least, according to references cited above 06-Feb-20 03:58 PM well the model 3 appears to work, the model 12 needs some TLC 06-Feb-20 03:58 PM <__ice9#6039> It looks like direct physical handling (brittle) or fairly high temperature thermal treatment are the main risk factors 06-Feb-20 04:14 PM ok I ordered a 1000mohm (maybe? i dunno) 1000x 40Kv probe... 06-Feb-20 04:14 PM 1000x will make it low resolution but eh... 06-Feb-20 04:14 PM at-least make sure I'm in the ballpark 06-Feb-20 04:14 PM I repair CRTs sometimes too so that'll be nice for that 06-Feb-20 04:15 PM one of the red ones with the banana plug ends? 06-Feb-20 04:15 PM yea 06-Feb-20 04:15 PM one of the ones everyone from china to BK precision sell 06-Feb-20 04:15 PM they're quite handy but fairly noisy and not super useful for anything over 60Hz-ish 06-Feb-20 04:15 PM but definitely good enough for this/that 06-Feb-20 04:16 PM oh I don't need it for resolution like that, I mean like voltage resolution 06-Feb-20 04:16 PM I'd only ever use it on DC voltage 06-Feb-20 04:16 PM or well 06-Feb-20 04:16 PM what SHOULD BE DC voltage 06-Feb-20 04:16 PM yeh they're quite alright for that 06-Feb-20 04:16 PM some CRT circuits can be very sick heh 06-Feb-20 04:16 PM but yea the problem is these ludlums pump out so little current 06-Feb-20 04:16 PM 10mohm is just not enough, one of ludlums manuals I saw said ATLEAST 1000mohm 06-Feb-20 04:17 PM oh, meter impedance tanks it huh 06-Feb-20 04:17 PM yea... 06-Feb-20 04:17 PM makes sense 06-Feb-20 04:17 PM it just pulls it down to 500V and it clicks forever 06-Feb-20 04:17 PM The model 3 works... but I was playing with the adjustment and I want to make sure its close before playing with it much more 06-Feb-20 04:17 PM make sure I'm not over driving it now or something 06-Feb-20 04:17 PM but yea... 06-Feb-20 04:17 PM totally had to take the stupid metal can off the smoke detector to get it to pick up and it had to be right up on the probe 06-Feb-20 04:17 PM but it clicks :) 06-Feb-20 04:18 PM >.> 06-Feb-20 04:18 PM the model 3 is from 91/92 timeframe so its quite new and clean 06-Feb-20 04:18 PM the model 12... is old... all transistors, model 3 was mostly 4000 series... 06-Feb-20 04:18 PM a fresh Am241 button registers something like 140,000 CPM on my 3+ 44-9 06-Feb-20 04:19 PM well I don't have it torn all the way down to the button 06-Feb-20 04:19 PM i noted the exact number someplace 06-Feb-20 04:19 PM ah 06-Feb-20 04:19 PM just got the covering can off 06-Feb-20 04:19 PM so there are still like 06-Feb-20 04:19 PM two metal barriers in there 06-Feb-20 04:19 PM definitely think it should probably be counting more though... 06-Feb-20 04:19 PM hrm 06-Feb-20 04:19 PM i wonder if spectrum techniques does bulk discounts 06-Feb-20 04:19 PM would be nice to find someone nearby with a check source 06-Feb-20 04:19 PM hrmm hehe 06-Feb-20 04:20 PM let's get a bunch of vacuum hackers branded 2.5uCi Cs137 sources :D 06-Feb-20 04:20 PM hehehe 06-Feb-20 04:23 PM <__ice9#6039> I built a 300kV probe validated to at least 580kHz 06-Feb-20 04:23 PM <__ice9#6039> I actually have no idea whether it goes any higher atm because I blew the FETs in my large RF Tesla coil, but sooner or later I should have more test examples 06-Feb-20 04:24 PM yea not torn down to the button but with the shield off I'm getting like 70Kcpm? 06-Feb-20 04:24 PM it looks like? 06-Feb-20 04:24 PM <__ice9#6039> The trick is to use a parallel capacitive voltage divider alongside the resistive divider and use a doubly nested EMI shield with the inner layer connected to the probe output 06-Feb-20 04:24 PM <__ice9#6039> And a lot of space between the inner shield and the divider to minimize stray capacitance-- and then the stray capacitance is used as the upper section of the capacitive divider 06-Feb-20 04:26 PM I found my BNC cable was damaged on mine and after rigging up a new one (with a proper replacement on the way) a button causes mine to overflow at 1M CPM with my G1LE probe 06-Feb-20 04:26 PM <__ice9#6039> @x44203 helped a lot with getting the design right 06-Feb-20 04:27 PM I think before finding the cable being somewhat faulty I was getting 130-140k CPM with a button 06-Feb-20 04:27 PM not entirely sure which to believe but I guess I'll find out when I get the new cable 06-Feb-20 04:29 PM honestly kinda just want to safely dispose of my Am241 button, i don't really feel safe having it around as a little thing when i've since gathered actual check sources/exempt material 06-Feb-20 04:29 PM it lives in a wholly unnecessary lead pig in dense foam so it's not gonna get lost, but, alas 06-Feb-20 04:30 PM <__ice9#6039> They stay pretty fresh for like a century, too. One might say, they are all still fresh 06-Feb-20 04:30 PM lol don't people just throw smoke detectors away? 06-Feb-20 04:31 PM they're not supposed to 06-Feb-20 04:31 PM you are technically supposed to send it back to the manufacturer at the end of its life 06-Feb-20 04:31 PM you really do live in California don't you... 06-Feb-20 04:31 PM its licensed source material, and, in particular, transactinide source material 06-Feb-20 04:31 PM this is federal 06-Feb-20 04:31 PM (though california is worse about a lot of things) 06-Feb-20 04:32 PM <__ice9#6039> glances at radium tube cheerfully radiating in lead castle 06-Feb-20 04:33 PM here get non-traceable ones then :) https://www.ebay.com/itm/Ion-Chamber-Metal-Geiger-Counter-Check-Test-Source-Smoke-Detector-Sensor/362683834508 06-Feb-20 04:33 PM You have one of the raw powder form radium paint vials? 06-Feb-20 04:33 PM "non-licensed" I suppose 06-Feb-20 04:33 PM <__ice9#6039> I mentioned this on Twitter at one point, but if you have like 10x of those Am ionization chambers, you can actually use the low energy gamma emissions to do XRF 06-Feb-20 04:33 PM i'm more interested in converging on a state where i can actually have a license and do things legitimately 06-Feb-20 04:34 PM go somewhere like VA, my friend just got a commercial building there 06-Feb-20 04:34 PM sorry 06-Feb-20 04:34 PM its actually zoned like light industrial 06-Feb-20 04:34 PM he could literally be making toxic materials there the town doesn't care 06-Feb-20 04:34 PM so long as you don't make a super fund site out of it of-course 06-Feb-20 04:35 PM <__ice9#6039> I have an exempt self-contained vial of powdered glowing pigment with radium, originally intended as a luminous dot much like current day tritium sources-- except nowhere near as shieldable 06-Feb-20 04:35 PM . o O (just because it's not illegal doesn't mean it's not stupid, inconsiderate, and unprofessional) 06-Feb-20 04:35 PM <__ice9#6039> The radium destroyed the pigment many years ago, granted 06-Feb-20 04:35 PM <__ice9#6039> But it's still there itself of course 06-Feb-20 04:35 PM neat 06-Feb-20 04:35 PM it is kinda interesting how radiolysis destroys the phosphors in those 06-Feb-20 04:36 PM <__ice9#6039> There's a little window with a porous substrate to vent the radon 06-Feb-20 04:36 PM I'd like to find radium sources like that at some point but for now I just have to work with the watch hands 06-Feb-20 04:36 PM <__ice9#6039> So it doesn't explode 06-Feb-20 04:36 PM <__ice9#6039> It was kind of costly. Got it from a very dedicated collector. NRC exempt radium related antique marketed to the general public. 06-Feb-20 04:36 PM <__ice9#6039> There were some rather unnerving comments about gamma burns in the item description 06-Feb-20 04:36 PM <__ice9#6039> So, it stays in its little castle, generally 06-Feb-20 04:37 PM I'd imagine if there was enough of the material 06-Feb-20 04:37 PM <__ice9#6039> Oh, there is 06-Feb-20 04:37 PM <__ice9#6039> As in, the seller got one 06-Feb-20 04:37 PM oh that thing 06-Feb-20 04:37 PM <__ice9#6039> Lolllll 06-Feb-20 04:37 PM I'm still trying to track down a tin of the watchmakers paint 06-Feb-20 04:37 PM <__ice9#6039> Yeah that thing 06-Feb-20 04:38 PM geoelectronics sells little laminated scintillator calibration cards with a smote of radium on them 06-Feb-20 04:38 PM if you just, like, want it for the spectrum 06-Feb-20 04:38 PM (on ebay, that is) 06-Feb-20 04:38 PM <__ice9#6039> Yeah they are all horribly damaged in the middle too, by radiation acting on the organics over decades 06-Feb-20 04:38 PM <__ice9#6039> It's kind of impressive 06-Feb-20 04:39 PM yeah :D 06-Feb-20 04:39 PM These? https://www.ebay.com/itm/RADIUM-Calibration-Card-Standard-RARE/292800554243?hash=item442c45e503:g:sgsAAOSwuyNbKQMt 06-Feb-20 04:40 PM yep! 06-Feb-20 04:40 PM mine measures around 38.5 kCPM on my 44-9 06-Feb-20 04:40 PM but it's also Lively At A Distance in a way that Am241 is not 06-Feb-20 04:41 PM <__ice9#6039> Yeah some of the gamma emissions need at least 2-3cm of lead to get decent shielding 06-Feb-20 04:41 PM <__ice9#6039> This is well beyond x-ray territory 06-Feb-20 04:42 PM i was kind of startled when it came in just a paper envelope with some cardboards around it 06-Feb-20 04:42 PM could pick it up, in the envelope, with my counter from a few feet back 06-Feb-20 04:42 PM <__ice9#6039> I want to try imaging and spectroscopy experiments with it when I have more tools ready 06-Feb-20 04:42 PM <__ice9#6039> Yeah mine came wrapped in lead sheeting, where it still stays. 06-Feb-20 04:43 PM https://twitter.com/profanegeometry/status/1194541979545161728 it has a very distinct spectrum 06-Feb-20 04:43 PM <__ice9#6039> It was quite loudly detectable through it regardless 06-Feb-20 04:43 PM <__ice9#6039> Pretty 06-Feb-20 04:43 PM <__ice9#6039> I like the indicator window aesthetics 06-Feb-20 04:43 PM <__ice9#6039> I am thinking of making some kind of lead pig with a sliding window to expose the sample for directing the gamma emissions at targets 06-Feb-20 04:43 PM <__ice9#6039> Maybe with some filtration options to selectively limit which wavelengths are used 06-Feb-20 04:45 PM I just keep what I can in a lead glass cookie jar lol 06-Feb-20 04:45 PM <__ice9#6039> That works for low energy gamma 06-Feb-20 04:45 PM <__ice9#6039> It doesn't work for this 06-Feb-20 04:45 PM <__ice9#6039> Lead glass is only about 25% lead 06-Feb-20 04:45 PM <__ice9#6039> And not thick enough 06-Feb-20 04:45 PM <__ice9#6039> It could also make a likely decent RaBe neutron source 06-Feb-20 04:45 PM <__ice9#6039> Though that would require owning more Be, which would need a fair amount of attention to containment first 06-Feb-20 04:49 PM i keep my radium card taped to a metal junction box plate with another metal disc covering the source in storage and it lives in a admittedly somewhat thin metal flip-top box with my other radioactive things, plenty to keep the at-surface radiation levels down to barely above background 06-Feb-20 04:49 PM i strongly do not recommend anyone put together any neutron emitters that can't be turned off 06-Feb-20 04:49 PM that seems to be the thing that every 'nuclear boyscout' type character tries and then ends up in the national news shortly therafter 06-Feb-20 04:50 PM <__ice9#6039> I can occasionally get a couple clicks from mine through the lead castle, but it's only barely above background. Attenuation figures are in line with expectations. It's tremendously loud with just its own sheet wrapping. 06-Feb-20 04:50 PM <__ice9#6039> Oh that would be very foolish. Such a thing would not be a permanent assembly 06-Feb-20 04:50 PM <__ice9#6039> Neutrons are too hard to shield 06-Feb-20 04:51 PM are modern tire weights still lead or are they all alloy these days? 06-Feb-20 04:53 PM <__ice9#6039> Actually NVM RaBe would require direct exposure of the source material. That's not happening. 06-Feb-20 04:53 PM what would be kind of neat (but still questionable) is something that can take a nuclespot and standard size of beryllium plate/disk/etc and couples them together in a sealed container at a distance, such that you can 'turn it on' by evacuating the air between the nuclespot and the beryllium 06-Feb-20 04:54 PM <__ice9#6039> Yeah that's similar to what I had in mind, but in my case the source material is a... powder. Which is not under any circumstances leaving its little glass vial. 06-Feb-20 04:54 PM <__ice9#6039> Beam on target is generally going to be a lot stronger, but it's also more costly and difficult to construct 06-Feb-20 04:54 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-185450-3B0B5.png 06-Feb-20 04:57 PM wonder how the Be(ɑ,n) cross section scales with energy 06-Feb-20 04:57 PM getting helions up to MeV might be a cyclotron-y affair 06-Feb-20 04:59 PM <__ice9#6039> MeV very often is, sadly 06-Feb-20 04:59 PM <__ice9#6039> RF linacs sometimes suffice, but often large 06-Feb-20 04:59 PM <__ice9#6039> Laser wakefield looks interesting 06-Feb-20 04:59 PM <__ice9#6039> Hmm from my reading it looks likely that this thing should work for gamma imaging. Will need to do some tests. 06-Feb-20 04:59 PM <__ice9#6039> @qualia meanwhile spallation is about 0.5-2.0 GeV for most targets, hence large national facilities 06-Feb-20 04:59 PM <__ice9#6039> ... I guess if it was originally meant for making things glow visibly enough to see from a hundred feet away, it has to work for imaging.... 06-Feb-20 05:05 PM gamma imaging with a multi-peak source sounds like an annoying signal processing exercise 06-Feb-20 05:06 PM <__ice9#6039> Filter with lead 06-Feb-20 05:06 PM <__ice9#6039> Long exposure camera directed at luminescent phosphor plate 06-Feb-20 05:06 PM <__ice9#6039> Should not be too difficult 06-Feb-20 05:06 PM <__ice9#6039> To do the hacky way at least 06-Feb-20 05:06 PM <__ice9#6039> Or just film itself 06-Feb-20 05:07 PM ah, i suppose so 06-Feb-20 05:08 PM <__ice9#6039> Metal and ceramics don't move, so it doesn't matter if the exposure takes an hour 06-Feb-20 05:32 PM <__ice9#6039> Hmm. Suspecting that this ZnS:Ag film I bought some time ago may be bad. At the time I only had thoria as an alpha source, but it doesn't glow from being placed over the surface of some 70k CPM uranium ore or a bare Am ionization chamber source either. Puzzling. 06-Feb-20 05:32 PM <__ice9#6039> Those should be strong enough alpha sources, I would have thought at least 06-Feb-20 05:32 PM <__ice9#6039> They work quite well with my alpha sensitive tube 06-Feb-20 05:32 PM <__ice9#6039> More research needed 06-Feb-20 05:32 PM <__ice9#6039> For gamma specific phosphors especially 06-Feb-20 05:32 PM <__ice9#6039> Though I am curious whether ZnS:Ag can go bad, or.. why in general it doesn't seem to detect anything even after lengthy visual acclimation 06-Feb-20 05:32 PM <__ice9#6039> Perhaps it would work better with a microscope 06-Feb-20 06:09 PM <__ice9#6039> Also my comment on glowing above is not true-- the mechanisms are different as that mainly relied on alpha 06-Feb-20 06:09 PM <__ice9#6039> Estimated activity is consistent though 06-Feb-20 06:18 PM That's the normal xray intensifier film right? 06-Feb-20 06:18 PM Is that supposed to be visible with an Am source or a high click count uranium ore? 06-Feb-20 06:18 PM I thought you needed moderate xray for them to be reasonably effective 06-Feb-20 06:19 PM <__ice9#6039> I have one of those as well, but this was purpose-built as a spinthariscope screen 06-Feb-20 06:19 PM <__ice9#6039> I don't think the x-ray phosphor panel should be visible from the gamma emissions from an isotope source. An x-ray tube with a typical collimator will direct 0.01-1W worth of x-rays through the screen for the duration of the period that it is operating. Not a close comparison. 06-Feb-20 06:22 PM I suppose I should see about picking up some films that can then 06-Feb-20 06:22 PM <__ice9#6039> Also I checked, and it does not appear to be visible from either of those two sources. 06-Feb-20 06:22 PM <__ice9#6039> The gamma imaging idea would require long exposure if it does work 06-Feb-20 06:22 PM I only have some 400 iso film that I use with my dslr for xray photos 06-Feb-20 06:22 PM <__ice9#6039> But a better portable pig is needed first, so that will have to wait a while 06-Feb-20 06:22 PM <__ice9#6039> Yeah that sounds right 06-Feb-20 06:25 PM I still need to get a tube for my microfocus xray controller and a digital dental xray sensor 06-Feb-20 06:25 PM You got that hamamatsu controller, right? 06-Feb-20 06:25 PM yeah 06-Feb-20 06:25 PM Can you get a bunch of teardown pics and ROM dumps? 06-Feb-20 06:25 PM I just bought another hamamatsu head, and while I know the pinout/control signals thanks to TecKonstantin, we still don't know the voltage/current curves and conditioning procedures 06-Feb-20 06:26 PM It's still not in my posession yet, but there were pictures taken of the inside, let me see if I can get ahold of them 06-Feb-20 06:29 PM @GigaSquirrel @qualia It was oxide shed from the rather large window of old Fiddler probes. The keyword here is old. They were regularly left uncovered and exposed to ambient air/humidity which slowly degraded them. Really, there's nothing you can do to stop this from happening short of encapsulation. Keep them covered whenever not in use to extend that oxidation time as long possible. If you have a case for your probe, toss your dessicant leftover packs in there. The other thing is surveillance of that case to see if you have degradation, which means sending swipes to an analytical lab, but that's probably a tall order for a hobbyist. But for relative risk, if you have a tool chest full of non-sparking BeCu alloy tools, that's a far bigger concern than your one probe. 06-Feb-20 06:31 PM https://cdn.discordapp.com/attachments/405849973960343564/675166613674393611/IMG_8012.JPG 06-Feb-20 06:31 PM https://cdn.discordapp.com/attachments/405849973960343564/675166616522063902/IMG_8011.JPG 06-Feb-20 06:33 PM Fairly low res, but it looks incredibly similar to my newer dead hamamatsu head 06-Feb-20 06:33 PM that firmware rom dump would be really helpful 06-Feb-20 06:33 PM but beware of that battery 06-Feb-20 06:33 PM the firmware might be volatile 06-Feb-20 06:33 PM @Treehouseman 06-Feb-20 06:36 PM <__ice9#6039> Do BeCu tools pose a Be exposure risk in practice? 06-Feb-20 06:36 PM Yes. 06-Feb-20 06:37 PM <__ice9#6039> I don't own any regardless, but that's very useful to know. 06-Feb-20 06:37 PM if the firmware is volatile then why is there a rev on the eprom? 06-Feb-20 06:37 PM maybe cal data is volatile 06-Feb-20 06:38 PM Something is volatile 06-Feb-20 06:38 PM I have a battery on mine too 06-Feb-20 06:38 PM is the eprom bad on yours? 06-Feb-20 06:38 PM <__ice9#6039> Interesting. Industry guidance suggests that it does not, but... there are conflicts of interest there. 06-Feb-20 06:38 PM I don't know if it's bad 06-Feb-20 06:38 PM But it's irrelevant since the tube is shattered and a lot of the oil is gone 06-Feb-20 06:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC02673-3CDA0.JPG 06-Feb-20 06:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC02671-66A8D.JPG 06-Feb-20 06:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC02672-70572.JPG 06-Feb-20 06:38 PM Three boards 06-Feb-20 06:39 PM well if you look at your eprom, you might find the command structure and I can dump the ram on mine before going for the eprom to be safe 06-Feb-20 06:39 PM Yeah just want to confirm 06-Feb-20 06:39 PM But I know the pinout of the controller if you get a head 06-Feb-20 06:39 PM The seller has some left, I will let you know if the one I get works. 06-Feb-20 06:39 PM (cheapish) 06-Feb-20 06:40 PM what was the cost on yours? 06-Feb-20 06:40 PM Under $400 including express shipping 06-Feb-20 06:40 PM and it's compatible with my controller? 06-Feb-20 06:41 PM Vaguely, ish, should be, kinda-sorta. 06-Feb-20 06:41 PM The big round connector looks the same 06-Feb-20 08:45 PM <__ice9#6039> Hmm I cast a pig for the exempt antique radium source with 3cm lead in all directions. So it's portable now without losing its effective on/off functionality 06-Feb-20 08:45 PM <__ice9#6039> Just melted a bunch of lead in a soup can, skimmed off the oxides, dunked a boro glass test tube down the center, and sprayed it with water until the surface layer froze thick enough to hold the tube in place. Then snapped off the protruding part of the tube to get clearance for a lid. 06-Feb-20 08:45 PM <__ice9#6039> Haven't cast the lid yet. Will probably just melt more lead in another soup can and saw off the unused height of the can. In the meantime, sitting a spare lead ingot on top of it is sufficient to provide 3cm coverage upward. 06-Feb-20 08:45 PM <__ice9#6039> Always best to use a good quality cartridge respirator or supplied air respirator while melting lead, particularly if you use a torch to speed it up. Prevents inhaling fumes. 06-Feb-20 09:03 PM <__ice9#6039> Also, about BeCu, I did find one article indicating a CBD hazard from casting and polishing operations 06-Feb-20 09:03 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-230135-66C7A.png 06-Feb-20 09:03 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200206-230159-E17EA.png 06-Feb-20 11:15 PM and it's compatible with my controller? @Treehouseman the connector is different, these heads have a 24p connectors (SRCN6A25-24P) 06-Feb-20 11:51 PM @Conmega congrats on the ludlums! 06-Feb-20 11:51 PM now you're part of the cool kids ️ 07-Feb-20 01:31 AM https://www.youtube.com/watch?v=wp1xCdZWw4o I might have overdone it a bit with the alpha sample 07-Feb-20 01:33 AM Did you make it? 07-Feb-20 01:33 AM And if so, out of what? 07-Feb-20 01:33 AM I'm assuming radon daughters? 07-Feb-20 01:33 AM But then radon daughters are all short lived and there's a Pb-210 to Po-210 jump of over 22 years 07-Feb-20 01:37 AM yep, it's my baby 07-Feb-20 01:37 AM 12 hours at -3 kV in a box containing some ore 07-Feb-20 01:37 AM should be the ideal sample for my alpha spectrometer, as the active layer will be really thin 07-Feb-20 01:39 AM And self-safing after a while 07-Feb-20 01:39 AM self-safing? 07-Feb-20 01:40 AM Decays to longer lived not alpha emitter 07-Feb-20 01:40 AM Pb210 07-Feb-20 01:40 AM yes 07-Feb-20 01:40 AM Still dirty but not too bad 07-Feb-20 01:42 AM dirty? 07-Feb-20 01:44 AM A nicely thin and totally unadhered layer of pb210 :p 07-Feb-20 01:44 AM Ready to smear everywhere 07-Feb-20 01:44 AM But not very hot 07-Feb-20 12:09 PM <__ice9#6039> Probably worth noting that e.g. 1W of 50keV x-ray photons (a fairly typical result from running a 1500W x-ray tube with a wide-angle collimator, though calculating as monochromatic for simplicity here) would be equivalent to a directional source of 3.3kCi or 207kCi omnidirectional for plausible aperture solid angle assumptions 07-Feb-20 12:09 PM <__ice9#6039> That is 37 TBq and 7.6 PBq respectively 07-Feb-20 12:10 PM A 1500W rotanode should get closer to 10W 07-Feb-20 12:10 PM <__ice9#6039> Yes but most will be blocked by the collimator 07-Feb-20 12:10 PM <__ice9#6039> As I noted 07-Feb-20 12:11 PM 2MCi at the source equivalent 07-Feb-20 12:11 PM <__ice9#6039> Uncollimated, yes, multiplying the above is reasonable 07-Feb-20 12:11 PM The mind boggles. 07-Feb-20 12:12 PM <__ice9#6039> And moreover: it gets worse if you relax the monochromaticity assumption, especially for those little beryllium window XRF tubes 07-Feb-20 12:12 PM Yeah it's a smeary gaussian output 07-Feb-20 12:12 PM <__ice9#6039> Because of the huge numbers of soft x-ray photons that survive the window instead of hitting the aluminum inherent filtration in medical tubeheads 07-Feb-20 12:12 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/production-of-x-rays-22-638-44897.jpg 07-Feb-20 12:13 PM at that point you get into the GCi equivalents 07-Feb-20 12:15 PM <__ice9#6039> Makes me think it might be interesting to treat materials with soft x-rays in vacuum produced between open electrodes for extended periods of time. It would be pretty simple to block if you keep kVp low, and I bet it does things pretty similar to plasma treatments and ebeam processing. There must be literature on this somewhere. 07-Feb-20 12:15 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/TLyJoAd2x_bbLW9tjrkb5kXwC2pLKhE2rAZ2NtfrRF-7C754.png 07-Feb-20 12:15 PM It gets less droopy the higher in voltage you go 07-Feb-20 12:15 PM <__ice9#6039> Indeed 07-Feb-20 12:16 PM But at low energies the spectrum is dominated by the characteristic peaks 07-Feb-20 12:16 PM <__ice9#6039> A well optimized neutron BoT generator producing 3.7*10^10 n/s is obviously 1 Ci, which is nasty enough as neutrons. But x-ray tubes are on another level entirely. 07-Feb-20 12:16 PM <__ice9#6039> Yes 07-Feb-20 12:16 PM I wonder why x-ray tubes aren't used as much in sterilization 07-Feb-20 12:16 PM <__ice9#6039> They are 07-Feb-20 12:16 PM They're a popular lab sterilizer 07-Feb-20 12:16 PM <__ice9#6039> I read a paper about this 07-Feb-20 12:16 PM But not food 07-Feb-20 12:16 PM <__ice9#6039> That's true 07-Feb-20 12:17 PM More of a "box you put things in to fry" 07-Feb-20 12:17 PM <__ice9#6039> Usually you would want to use a big rotanode tube for an extended period of time 07-Feb-20 12:17 PM Rather than "room you never walk into" 07-Feb-20 12:17 PM <__ice9#6039> Yeah I've used them in a cancer bio lab in the past 07-Feb-20 12:17 PM <__ice9#6039> Cancer stem cells are almost immune to radiation 07-Feb-20 12:17 PM <__ice9#6039> We hit them with 32 Gray of x-rays in a few minutes, and everything else on the plate died 07-Feb-20 12:17 PM <__ice9#6039> But 2 days later the stem cells were building new tumors again 07-Feb-20 12:17 PM <__ice9#6039> It was one of the most disturbing things I have ever seen in my life 07-Feb-20 12:19 PM Shows why radiotherapy is hard 07-Feb-20 12:19 PM <__ice9#6039> Radiotherapy kills the bulk mass of the tumor, that's it. 07-Feb-20 12:19 PM <__ice9#6039> It cannot and will not kill the stem cells, except to the extent that they go down with the ship due to massive necrosis of the surrounding tumor and thermal effects 07-Feb-20 12:19 PM <__ice9#6039> Likewise most chemotherapy drugs are largely ineffective on the stem cells. They use a different method of replicating their genome. 07-Feb-20 12:19 PM <__ice9#6039> Some things do seem to work. Substances that promote oxidative stress, reactive oxygen species. Inhibitors of polymerases gamma and beta, though catching mitochondria in the crossfire becomes an issue for pol gamma; beta is more promising. 07-Feb-20 12:19 PM <__ice9#6039> Hyperthermia also kills them, seemingly just due to downstream effects on ROS 07-Feb-20 12:19 PM <__ice9#6039> The Warburg effect, glucose restriction whether dietary or via metformin, can sometimes win some initial battles-- but they often evolve around it later on 07-Feb-20 12:19 PM <__ice9#6039> Massive doses of vitamin C, salinomycin or the recent optimized 'ironomycin' both act via ROS as well 07-Feb-20 12:19 PM <__ice9#6039> Many substances traditionally used as abortifacients, actually 07-Feb-20 12:19 PM <__ice9#6039> Because the stem cells are trying to build new organs 07-Feb-20 12:19 PM <__ice9#6039> Anyway this is all tangential. But I thought it might be interesting to some people. 07-Feb-20 12:35 PM <__ice9#6039> Anyway, about x-ray sterilization, this write-up suggests accelerator sources of a few MeV are typical for equipment, basically just competing with a typical Co-60 source but with more versatility: http://iiaglobal.com/wp-content/uploads/2018/01/White-Paper-Comparison-Gamma-Eb-Xray-and-EO-for-Sterilisation.pdf 07-Feb-20 12:35 PM <__ice9#6039> Lower energy levels work for food though https://www.scientificamerican.com/article/x-ray-machines-food/ 07-Feb-20 12:39 PM Soft x-rays, especially the charateristic peaks are much easier to shield and will be blocked easily by any bulk material, so it's not very suitable for a processing a lot of organic materials through packaging and so on 07-Feb-20 12:39 PM You also want a uniform dose distribution within targets of a variety of shapes, so higher energy machines are the way to go for industrial sterilization. 07-Feb-20 12:39 PM On the point of sealed tube neutron sources, they only scale to a certain point... After 10^10 neutrons per second the size and cost start becoming ridiculous very quickly 07-Feb-20 12:43 PM <__ice9#6039> Yes, more interesting for spectroscopy and perhaps material surface treatments 07-Feb-20 12:43 PM <__ice9#6039> Yep, hundreds to thousands of keV most common 07-Feb-20 12:43 PM <__ice9#6039> Doses of at least a few kGy for bacterial control. Even 200 Gy will kill almost all insects in produce though. 07-Feb-20 12:45 PM I am really interested in large compact BoT neutron sources, but for huge ones the yield is actually limited by the gas target number density, the only way to increase the yield after you achieve a certain beam current density is to actually stretch your target deeper 07-Feb-20 12:45 PM Then collisions cause the deuterons to slow down, and you only get a concentrated region of neutron emission, makes collimation and so on harder 07-Feb-20 12:46 PM <__ice9#6039> Hmm I was talking about benchtop-sized turbopumped ion accelerator beam-on-target systems more so than sealed ones, but yeah the literature suggests 10^10-10^11 for D-D is currently about as good as it gets. D-T is consistently about 100x as many events across a wide range of designs. 07-Feb-20 12:46 PM <__ice9#6039> Huh interesting 07-Feb-20 12:47 PM Yeah, that's the target limitation there. Increasing gas density is not trivial, you'd need massive differtial pumping or fancy plasma windows 07-Feb-20 12:47 PM <__ice9#6039> Gas target number density? 07-Feb-20 12:48 PM At that scale solids loaded with deuterium will not do anymore, I'm talking beyond 10^11 here 07-Feb-20 12:48 PM <__ice9#6039> Higher ion beam supply gas, or do you mean a more densely saturated target? 07-Feb-20 12:48 PM <__ice9#6039> Fascinating 07-Feb-20 12:48 PM <__ice9#6039> So maybe hit liquid deuterium in a dewar? Terrible way to treat liquid hydrogen though. Will be lots of thermal losses. 07-Feb-20 12:48 PM <__ice9#6039> What about lithium deuteride...? 07-Feb-20 12:49 PM Then the stopping distance of the beam may become a bigger issue 07-Feb-20 12:49 PM The beam lose energy so fast that you don't get to penetrate the surface of the target before you fall below the optimal cross section range 07-Feb-20 12:50 PM <__ice9#6039> But how does LiD compare to TiD? 07-Feb-20 12:50 PM The ion energy is quite low here so stopping distance in solids is short. I'm actually quite curious to how liquid deuterium will perform, might run a little TRIM/FLUKA simulation to find out 07-Feb-20 12:51 PM <__ice9#6039> I'm just thinking of things that worked well in thermonuclear weapons 07-Feb-20 12:51 PM <__ice9#6039> Mostly neutron-driven though 07-Feb-20 12:52 PM Well in weapons the mechanism is mostly thermanuclear fusion in the initial plasma ball that has high enough ion temperature 07-Feb-20 12:52 PM In BoT systems the densities are much lower 07-Feb-20 12:55 PM <__ice9#6039> I know that lol 07-Feb-20 12:55 PM <__ice9#6039> I was simply thinking about various fusion target materials that have been tried in the past 07-Feb-20 12:55 PM <__ice9#6039> Current weapons are mostly lithium deuteride 07-Feb-20 12:55 PM <__ice9#6039> Maybe even entirely, not sure 07-Feb-20 12:55 PM <__ice9#6039> https://en.wikipedia.org/wiki/Plasma_window this is very interesting, though it needs a lot of power and cooling 07-Feb-20 12:55 PM <__ice9#6039> Maybe a deuterium one might be a better confined target than something like a fusor grid or TiD thin film 07-Feb-20 12:55 PM <__ice9#6039> LiD is interesting to me because of the possibility of generating and then fusing some tritium within the target. Some of the literature suggests that it does improve n/s for the same system, holding all else constant, starting with a 50-50 D-T target, but not as much so as using a 100% T target and a D beam. But that it is sustainable, supposedly. 07-Feb-20 12:59 PM When you say lithium deuteride, you mean with natural lithium right? Not enriched with Li-6? 07-Feb-20 12:59 PM For in-situ breeding, I think you'd need some enrichment 07-Feb-20 01:00 PM <__ice9#6039> Yes, but I'm not sure whether the energy level is sufficient to do it in one of these 07-Feb-20 01:03 PM The neutron energies are definetely high enough for the lithium capture cross section 07-Feb-20 01:03 PM In fact the neutrons should be moderated a bit before they reach the maximum peak for breeding around 0.3 MeV 07-Feb-20 01:07 PM <__ice9#6039> Li-7 does work but it's endothermic and the cross-section is not great 07-Feb-20 01:07 PM <__ice9#6039> Li-6 is better 07-Feb-20 01:07 PM <__ice9#6039> if utilization is good, Li-7 is still a net win 07-Feb-20 01:07 PM <__ice9#6039> But it's less favorable 07-Feb-20 01:07 PM <__ice9#6039> It does seem to work better at high energy levels, again citing the Castle Bravo example 07-Feb-20 01:07 PM <__ice9#6039> Li-6 yes works better moderated 07-Feb-20 01:07 PM <__ice9#6039> That's consistent with prior reading 07-Feb-20 01:07 PM <__ice9#6039> Actually yes this doesn't quite work 07-Feb-20 01:10 PM The target density is so low that the material doesn't really moderate much and the initial neutron flux is very low compared to weapons with a primary fission stage 07-Feb-20 01:11 PM <__ice9#6039> It does need enrichment, as the Li-7 capture will mainly only occur on neutrons coming from a D-T event in the first place 07-Feb-20 01:11 PM Yeah 07-Feb-20 01:11 PM <__ice9#6039> Yes I recognize that. 07-Feb-20 01:11 PM <__ice9#6039> The issue is that the required neutron energy in practice for Li-7 + D is at least about 4MeV which exceeds the energy of the D-D produced neutron 07-Feb-20 01:12 PM It is interesting to see just how high the Li-6(n, alpha) cross section is 07-Feb-20 01:12 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/X4sPlotZvd2-65E13.png 07-Feb-20 01:13 PM <__ice9#6039> Solving the appropriate system of equations for equilibrium subject to some kind of plausible utilization efficiency assumption would indicate the amount of Li-6 enrichment required, but I suspect the answer is 'a lot' 07-Feb-20 01:13 PM <__ice9#6039> Since Li-7 essentially just gives you back the tritium used to get the neutron to fuse it in the first place, plus another neutron, at some small net cost in energy 07-Feb-20 01:13 PM <__ice9#6039> It can't sustain itself independently of externally provided tritium 07-Feb-20 01:13 PM <__ice9#6039> Which could come from Li-6 07-Feb-20 01:13 PM <__ice9#6039> I think that has regulatory obstructions though 07-Feb-20 01:18 PM Oh there's plenty of regulartory obstructions here. As you mentioned, the neutron dose is insane if the flux is high enough to start breeding meaningful amount of tritium 07-Feb-20 01:20 PM <__ice9#6039> That can be shielded, though with much more bulk than x-ray tubes require. 07-Feb-20 01:20 PM <__ice9#6039> But yes I suspect the efficiency might be poor at typical benchtop scales 07-Feb-20 01:20 PM <__ice9#6039> Which may make it rather irrelevant to improving their performance, idk 07-Feb-20 01:21 PM Wish they would sell borated polyethylene sheets for cheaper... 07-Feb-20 01:21 PM <__ice9#6039> Why not just use borated water absorbed into sodium polyacrylate? 07-Feb-20 01:22 PM Hmm, on a large scale is that cheaper? 07-Feb-20 01:22 PM <__ice9#6039> But meanwhile I'm not sure whether it is even legal to enrich Li-6 period, trying to find out since I am curious. It's obviously not for fissile isotopes but I don't actually know for non-fissile ones 07-Feb-20 01:22 PM <__ice9#6039> Lol yes by a lot 07-Feb-20 01:22 PM <__ice9#6039> Boric acid is dollars per kilogram 07-Feb-20 01:23 PM Can you cast it into sheets with some structural integrity? 07-Feb-20 01:23 PM <__ice9#6039> Sodium polyacrylate is used in water absorbing powders/granules and stores about 600-800x its own weight in water 07-Feb-20 01:23 PM <__ice9#6039> No you still need a bag for it 07-Feb-20 01:23 PM <__ice9#6039> Or something 07-Feb-20 01:23 PM <__ice9#6039> But it won't leak 07-Feb-20 01:23 PM <__ice9#6039> It's a blob instead of a liquid 07-Feb-20 01:25 PM Hmm, thanks for the heads-up, that's interesting. Also a bit worried about the long term stability since it is sort of a wet material 07-Feb-20 01:26 PM <__ice9#6039> Just use a lower fluids loading 07-Feb-20 01:26 PM <__ice9#6039> I don't see anything about lithium enrichment restrictions aside from banning export of the equipment so far, still reading 07-Feb-20 01:27 PM It's the tritium handling, storage and processing that's the problem afaik 07-Feb-20 01:27 PM <__ice9#6039> It does look pretty difficult tbf but there are papers running to like 60% at bench scale 07-Feb-20 01:27 PM <__ice9#6039> That's possible 07-Feb-20 01:27 PM <__ice9#6039> Past discussion here suggested that was regulated even if generated and consumed entirely in situ 07-Feb-20 01:27 PM <__ice9#6039> U.S. tritium regulations are a bit more strict than elsewhere, granted 07-Feb-20 01:27 PM <__ice9#6039> Hmm but anyway as far as D-D goes: definitely curious about sims of liquid deuterium (downward ion beam into Dewar) or a narrow plasma wall (e.g. 1cm²) of deuterium 07-Feb-20 01:27 PM <__ice9#6039> Both should have rather minimal beam attenuation, though I'm not certain whether the plasma confinement system itself would divert or slow the beam too much before it can actually impact 07-Feb-20 01:34 PM lithium enrichment is in fact one of those sensitive precursor things 07-Feb-20 01:34 PM i haven't seen it spelled out as clearly as e.g. deuterium but have seen it strongly hinted at, so 07-Feb-20 01:37 PM One problem with stopping distance in solids vs gas is the momentum transfer of the target atom after collisions. The collison of one high energy ion can cause a cascade in the solid lattice where there is no chance of fusion, whereas in gases it's not a problem. This is part of the problem with scaling to larger solid targets 07-Feb-20 01:37 PM <__ice9#6039> Tritium is definitely a problem. 07-Feb-20 01:37 PM <__ice9#6039> I do not see an explicit licensing restriction on lithium enrichment except for export of the equipment. I do see many limited exemptions for tritium, which implies in general that it does require licensing in that kind of application. That is also consistent with my reading on D-T neutron generators. It is not 100% clear to me whether it matters if no external tritium is used, but I am pretty sure that it does not-- possession of a given amount in mCi terms appears to be the determining factor regardless of how it was obtained or whether one ever has any kind of direct isolated access to it. 07-Feb-20 01:37 PM <__ice9#6039> This is my reading at present. Tritium processing itself may have additional restrictions. But it appears at present that simple possession already requires a specific license in the U.S. 07-Feb-20 01:44 PM D-T generators are definitely at least generally licensed devices in the US 07-Feb-20 01:44 PM <__ice9#6039> General license is fine lol 07-Feb-20 01:44 PM <__ice9#6039> Specific is the issue 07-Feb-20 01:44 PM Fine up to a point I think 07-Feb-20 01:44 PM do you have a general license already? 07-Feb-20 01:44 PM <__ice9#6039> They are self-executing...? 07-Feb-20 01:44 PM <__ice9#6039> I assume you are speaking in the same terms that I am. 07-Feb-20 01:44 PM <__ice9#6039> NRC general licenses are self-executing and do not require application or notification to the NRC itself. They only require compliance with certain relatively basic inventory tracking, radiation protection, and very basic recordskeeping stipulations, as well as notification if any material beyond certain thresholds is ever lost or stolen, and are subject to certain ceilings on the amounts of source materials possessed at any given point or imported/exported or sold or transferred domestically 07-Feb-20 01:44 PM <__ice9#6039> They are the mechanism by which it is legal to possess, for instance, a few kilograms of depleted uranium-- just as one of the more common examples 07-Feb-20 01:44 PM <__ice9#6039> Possession of quantities of tritium sufficient to be useful in neutron generators does not appear to be covered by any general license provisions 07-Feb-20 01:44 PM <__ice9#6039> So that is a problem for D-T generators 07-Feb-20 01:44 PM <__ice9#6039> Hence my comments above. 07-Feb-20 01:48 PM No, they aren’t generally licensed. That has a very different regulatory meaning. But, they are legal for sale in the US. 07-Feb-20 01:49 PM <__ice9#6039> That's even more interesting. 07-Feb-20 01:49 PM huh. 07-Feb-20 01:49 PM <__ice9#6039> But I suspect their manufacture probably requires a specific license 07-Feb-20 01:49 PM It also depends on the amount of tritium in the sealed tube 07-Feb-20 01:50 PM They are considered radiation producing machines that incorporate radioactive sources. The source may be licensed, but the machine is FDA CDRH approved. 07-Feb-20 01:50 PM i wish these regulations were easier to understand and navigate 07-Feb-20 01:51 PM <__ice9#6039> Btw, I am fairly sure @funranium cannot see anything I type, which may be a reaction to a debate we had about brands of OD7+ laser protection goggles on Twitter some time ago. Frankly I was quite amicable, so I was a bit puzzled by that. My only contention was that there exist goggles under $200 that are actually in line with their stated specs. 07-Feb-20 01:51 PM someone needs to put together a Dumb Idiot's Guide To Not Angering The NRC 07-Feb-20 01:52 PM <__ice9#6039> Which is a bit frustrating. He may feel free to inform me here if that is not the case, but my inability to add reactions strongly suggests that I am blocked here. 07-Feb-20 01:52 PM <__ice9#6039> Hmm yes anyway reading large tracts of the NRC regulations themselves is part of the process 07-Feb-20 01:52 PM <__ice9#6039> But the rest is looking for guidance from actual industry professionals familiar with the interpretive matters 07-Feb-20 01:54 PM Sadly, the NRC isn’t the only agency out there that has piece of the pie. 07-Feb-20 01:55 PM <__ice9#6039> Yep I'm invisible 07-Feb-20 01:55 PM A website with a single line of text saying "Can I: " and a looooooooooooong dropdown box with a search feature 07-Feb-20 01:55 PM Select what you want and it shows a big 72pt "NO" or 12pt "yes" 07-Feb-20 01:56 PM <__ice9#6039> Anyway the approach of FDA licensing the machine but NRC specific licensing the source and also further licensing (with the different specific license) the manufacture of the source or the source material itself is pretty common 07-Feb-20 01:56 PM <__ice9#6039> Some such completed devices, notably things like Co-60 sterilizers and radiation therapy machines, also require a facility specific license to own and operate 07-Feb-20 01:56 PM <__ice9#6039> Others, like tritium lighted exit signs, only need licenses to produce but not to own 07-Feb-20 02:00 PM And the key to working with General Licenses is that they approve a very specific isotope, quantity, configuration, and application. The moment you violate that, you aren’t covered by the general license anymore. 07-Feb-20 02:01 PM <__ice9#6039> Yes that's correct. 07-Feb-20 02:01 PM <__ice9#6039> Each isotope has quantity limits and you need to have particular reasons for owning and using it -- this is for general licenses applicable to source materials, in particular 07-Feb-20 02:01 PM <__ice9#6039> The quantity limits for depleted uranium and thorium are in the kilograms 07-Feb-20 02:01 PM <__ice9#6039> Uranium also has some additional rules involving fissile isotope activity limits 07-Feb-20 02:01 PM <__ice9#6039> So for instance, these are some examples. The bottom one about radium antiquities is the provision that allows me to own my Undark glass vial Ra-226 source, as one example. 07-Feb-20 02:01 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200207-160731-4C057.png 07-Feb-20 02:01 PM <__ice9#6039> Note there technically is not a limit on the activity of an antiquity, except that it must have been intended for use by the general public. So luminous markers, radium ceramic quack items, etc. are ok, but sterilization sources would not be, etc. 07-Feb-20 02:01 PM <__ice9#6039> Again just examples 07-Feb-20 02:01 PM <__ice9#6039> https://www.nrc.gov/materials/miau/general-use.html These are for devices. General licenses of source material possession are in a different section 07-Feb-20 02:14 PM i do not believe that permits modification or alteration of said radium antiquities, though, fwiw 07-Feb-20 02:14 PM <__ice9#6039> I might also note that abandoning a generally licensed source is forbidden 07-Feb-20 02:14 PM <__ice9#6039> Yes, that's correct. 07-Feb-20 02:14 PM <__ice9#6039> That's one of several reasons I mentioned that the material could never leave its housing 07-Feb-20 02:14 PM ah, missed that 07-Feb-20 02:14 PM i heard something about pulverizing things and got very worried yesterday 07-Feb-20 02:15 PM <__ice9#6039> But the main one is more direct: because it would result in contamination that would be very difficult to correct. 07-Feb-20 02:15 PM <__ice9#6039> Huh 07-Feb-20 02:15 PM <__ice9#6039> That was not me 07-Feb-20 02:15 PM <__ice9#6039> What occurred in that discussion was: I recalled that I did have a radium source, and that RaBe sources are a thing-- but then I remembered that most of the alpha emission is blocked, except at the open end of the vial through the cover material, and that RaBe/AmBe sources are often finely mixed rather than just being a Be plate over the α emitter because of limited penetration depth. That was infeasible, as I noted at the time. 07-Feb-20 02:15 PM <__ice9#6039> BoT devices, much like the analogy between x-ray tubes and low energy gamma emitters, also have several orders of magnitude higher flux than regulatorily and economically viable radionuclide alternatives 07-Feb-20 02:15 PM <__ice9#6039> As far as I can discern at present, though, there really is a wall blocking off experimental D-T BoT neutron generator R&D absent a specific license. 07-Feb-20 02:15 PM <__ice9#6039> Specific license application fees can run into the hundreds of thousands of dollars and if granted usually involve relatively burdensome logging and reporting obligations, as well as the possibility of site visits and inspections 07-Feb-20 02:15 PM <__ice9#6039> This is typically unacceptable for mere amateur experiments 07-Feb-20 02:15 PM <__ice9#6039> It can create material obstacles even for new or established businesses in relevant industry niches 07-Feb-20 02:15 PM <__ice9#6039> Incidentally, I tried an experiment recently with a high frequency DC 12kV 200μA power supply and was able to produce x-rays detectable by a simple Geiger counter without even lighting the filament. To be frank, I am not actually sure why this was possible. Interposing a smoothing capacitor seemed to make a small difference, but it was difficult to tell. I should have more precise measurement equipment soon, though. 07-Feb-20 02:37 PM believe that's field emission electron bremsstrahlung at work 07-Feb-20 02:37 PM <__ice9#6039> So I tried that as a last ditch and got something 07-Feb-20 02:37 PM <__ice9#6039> My guess was field emission too but I'm puzzled given the low voltage 07-Feb-20 02:37 PM 12kV is plenty in a hard vacuum to get detectable x-rays 07-Feb-20 02:38 PM <__ice9#6039> Vacuum quality is very good too, tested with my own handheld Tesla coil lolol 07-Feb-20 02:38 PM the one time i've produced xrays was at around 11-12kV iirc in a 10^-7 vacuum 07-Feb-20 02:38 PM just a little bit of tungsten wire between electrodes biased above ground, no heating or anything 07-Feb-20 02:38 PM <__ice9#6039> Huh ok, that must be it then 07-Feb-20 02:39 PM (if it was work-function hot the x-ray emission from that experiment would've been dramatically higher) 07-Feb-20 02:39 PM <__ice9#6039> The tube's internal shielding turned out to be very high quality, though I have some doubts about the long-term vacuum integrity of the window seals based on a 4hv thread 07-Feb-20 02:39 PM <__ice9#6039> Yeah that sounds right 07-Feb-20 02:39 PM i wouldn't rely on that at only 12kV 07-Feb-20 02:39 PM and with a cold cathode 07-Feb-20 02:40 PM <__ice9#6039> I tested pretty thoroughly 07-Feb-20 02:40 PM <__ice9#6039> The only areas above background were conical regions emanating from the windows 07-Feb-20 02:40 PM <__ice9#6039> Just used a tool to hold the counter probe and sweep through the space 07-Feb-20 02:41 PM as your voltage and current go up that will very likely cease to be the case 07-Feb-20 02:41 PM <__ice9#6039> We'll see. Integral shielding is quite thick. 07-Feb-20 02:44 PM what's the anode material? 07-Feb-20 02:58 PM <__ice9#6039> Mo 07-Feb-20 06:09 PM hrm well poking in the model 12 this is quite an old one, going to be fun to referb it without any schematics, the only electrolytic cap looks sad but its an axial 400uf 6v... 07-Feb-20 06:09 PM which is like impossible to get, or its a 400 minimum order at like 3 bucks a pop... which yea no 07-Feb-20 06:09 PM https://ludlums.com/images/product_manuals/M12.pdf 07-Feb-20 06:09 PM Serial Number 218039 and Succeeding Serial Numbers 07-Feb-20 06:09 PM any voltage equal to or higher than 6v should work 07-Feb-20 06:10 PM I found an older one that says like serial number 100K or something 07-Feb-20 06:10 PM but still... yea no the front plate layout is WAY different 07-Feb-20 06:10 PM this is a super old one 07-Feb-20 06:10 PM either way, I understand that @qualia still doesn't mean the 16V one isn't 400 minimum order at like 5 bucks a pop 07-Feb-20 06:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1990Oct-M12-SN78629-1D8F9.pdf 07-Feb-20 06:10 PM also at some point they get too big for the cramped space 07-Feb-20 06:11 PM oh zoinks 07-Feb-20 06:11 PM might be worth possibly getting different values and doing some silly things 07-Feb-20 06:11 PM series/parallel what have you 07-Feb-20 06:11 PM but yea 07-Feb-20 06:11 PM manual for your model ^ 07-Feb-20 06:11 PM lol no 07-Feb-20 06:11 PM much newer still 07-Feb-20 06:11 PM that uses 4000 series 07-Feb-20 06:11 PM this uses discrete transistors/diodes/etc 07-Feb-20 06:12 PM model 12 serial numbers 78629 onward 07-Feb-20 06:12 PM do you have an LCR meter? 07-Feb-20 06:12 PM you can always email them and ask for one, from what I've heard ludlum is pretty responsive 07-Feb-20 06:12 PM no its something I've been meaning to get for a long time, I may get one of those cheap chinese component testers though, they at-least get you a rough idea of if you have a resistor or something resembling a capacitor 07-Feb-20 06:12 PM do get one! 07-Feb-20 06:13 PM yesss 07-Feb-20 06:13 PM highly recommend those goofy things 07-Feb-20 06:13 PM get one with the tft lcd 07-Feb-20 06:13 PM not the graphical one 07-Feb-20 06:13 PM ... double check any numbers you get out of it with another instrument, but 07-Feb-20 06:13 PM you can flash 3 pages worth of functions on it 07-Feb-20 06:13 PM also, I will try emailing them then, thanks Spirit 07-Feb-20 06:13 PM better'n nothin' 07-Feb-20 06:13 PM @Spirit got a link to that one? 07-Feb-20 06:13 PM honestly I've just been trying to find the darn serial number on this thing 07-Feb-20 06:13 PM i'm not sure which i have now 07-Feb-20 06:13 PM oh 07-Feb-20 06:13 PM I bet its that 07-Feb-20 06:13 PM stamped into the casting 07-Feb-20 06:13 PM it may be on the pcb someplace 07-Feb-20 06:13 PM oh that too 07-Feb-20 06:14 PM 5593... 07-Feb-20 06:14 PM https://www.ebay.com/itm/NEW-TFT-GM328-Transistor-Tester-Diode-LCR-ESR-meter-PWM-Square-wave-Generator/352623957440 @qualia 07-Feb-20 06:14 PM I bought this one 07-Feb-20 06:14 PM flashed it successfully 07-Feb-20 06:14 PM oh wow 07-Feb-20 06:14 PM it /does stuff/ 07-Feb-20 06:14 PM fairly accurate too 07-Feb-20 06:14 PM within ballpark of good enough 07-Feb-20 06:16 PM might as well chuck a kit in the cart 07-Feb-20 06:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_2954-29CBC.JPG 07-Feb-20 06:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_2955-4F696.JPG 07-Feb-20 06:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200207_211705-D64AD.JPG 07-Feb-20 06:17 PM ooh that's lovely 07-Feb-20 06:19 PM yes, quite old some neat zener diodes in a dark blue glass, another diode in a solid gold casing, and lots of pretty cans 07-Feb-20 06:19 PM the whole hinging of the boards is cool too 07-Feb-20 06:19 PM man I wonder if anyone at ludlum still remembers this design 07-Feb-20 06:39 PM hrm yea so there is HV, just not reading any pulses 07-Feb-20 06:40 PM See if you can pick up the pulses at the series resistor with a scope 07-Feb-20 06:42 PM you mean where the HV passes through two series resistors with a capacitor to ground in the center and another capacitor off the probe side to some more resistors for reading here? 07-Feb-20 06:43 PM It'd essentially be the ground side of the tube to meter ground 07-Feb-20 06:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_2956-7EDE2.JPG 07-Feb-20 06:43 PM if it's also using a divider you can just go into the divider 07-Feb-20 06:44 PM badly labeled HV and P(robe) on there 07-Feb-20 06:44 PM you can see the 3 HV posts 07-Feb-20 07:02 PM ah... boy... 07-Feb-20 07:02 PM these are germanium transistors some of these 07-Feb-20 07:02 PM lots of 2n1302s 07-Feb-20 07:02 PM http://www.njsemi.com/datasheets/2N1302%20-%202N1308.pdf 07-Feb-20 07:18 PM Maybe you can ask @GigaSquirrel for some spare germanium so you can make some replacements :P 07-Feb-20 07:25 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200207_222515-93F45.JPG 07-Feb-20 07:25 PM Starting to work back on this here, will be interesting to see what failed in the counting circuitry. Then more interesting to find a replacement transistor if its one of those. 07-Feb-20 07:27 PM P is the probe? 07-Feb-20 07:27 PM What's the other side of the probe connected to? 07-Feb-20 07:28 PM I had it hooked to either the actual 44-9 probe or my multimeter before, just to see if I could have it do the same thing my model 3 did. either way I get no clicks or counts 07-Feb-20 07:29 PM no, I mean the 2 wires of the probe 07-Feb-20 07:29 PM is one side direct to ground? 07-Feb-20 07:29 PM Let me get a bit more of this drawn up, hopefully I can figure out where this ends up going over to those capacitors for the ranges or the piezo before long 07-Feb-20 07:29 PM I assume so 07-Feb-20 07:29 PM actually yes yes it is 07-Feb-20 07:29 PM yea all the shielding for those HV lines go right to ground every time 07-Feb-20 07:29 PM god ok I see to get over to the capacitors for the counting it goes through all of those transistors in some way or form 07-Feb-20 07:29 PM I just want to be cautious about hooking my scope up to points here 07-Feb-20 07:29 PM But I assume if I have the probe hooked up and the output voltage is near what it should be and I have the Americium button up to it I should see pulses on the scope on pretty much all the transistors emitters in some form or another 07-Feb-20 07:29 PM I just don't want to blow an input on one of my scopes 07-Feb-20 07:34 PM I'm gonna look real quick for the schematic for your version 07-Feb-20 07:35 PM good luck, I tried lol 07-Feb-20 07:37 PM What's your serial? 07-Feb-20 07:38 PM 5593 I believe 07-Feb-20 07:38 PM aka super early 07-Feb-20 07:38 PM I think I found a date code of 1974 for reference 07-Feb-20 07:38 PM yea this is from late 60s/early 70s design I believe 07-Feb-20 07:38 PM their catalog cover from 1963 shows the same selector nob and fron panel layout outside of the dial indicator being a more sturdy design on mine 07-Feb-20 07:38 PM https://ludlums.com/images/company/1963-Ludlum-Catalog-Cover.png 07-Feb-20 07:52 PM Ah I see a division in the circuit between the HV and the low voltage I think finally? 07-Feb-20 07:56 PM You can always check it with your multimeter 07-Feb-20 07:56 PM since you know you won't overload the meter due to burden 07-Feb-20 07:58 PM yea but if its pulsing I dunno what it would think of that 07-Feb-20 08:24 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Image-DFBAA.jpg 07-Feb-20 08:24 PM So that is the HV side of things I believe 07-Feb-20 08:24 PM that 10 ohm passes down to the rest of the madness 07-Feb-20 09:25 PM ok all of that checks out on the scope 07-Feb-20 10:20 PM it has a 1N3712 germanium tunnel diode in there wow... heh... 07-Feb-20 10:27 PM Would anyone have a spare mhv male to mhv male cable lying around? I just realized my meter doesn't use bnc, I could possibly swap the connector on the meter to bnc but I don't want to open the probe 07-Feb-20 10:27 PM you can stuff bnc into mhv by slightly trimming the bnc connector 07-Feb-20 10:27 PM That tunnel diode might be unobtainium. 07-Feb-20 10:28 PM Annoyingly the cheapest legit cables I can find are like $70 07-Feb-20 10:28 PM Made to order 07-Feb-20 10:29 PM they're just regular coax 07-Feb-20 10:29 PM you can buy mhv plugs and sockets pretty cheap too 07-Feb-20 10:29 PM Yeah, but the proper cable or making one with proper ends is still expensice 07-Feb-20 10:29 PM it's not 07-Feb-20 10:29 PM just buy a metal gland connector 07-Feb-20 10:30 PM For like $20 a connector if you don't want to order from china 07-Feb-20 10:30 PM though sadly genuine mhv is often expensive 07-Feb-20 10:30 PM yeah 07-Feb-20 10:30 PM you can buy them for $3 from china though 07-Feb-20 10:31 PM If I had a way to crack open the probe I'd possibly just solder a coax between them directly but while the back has screws it seems like it might be glued in place 07-Feb-20 10:32 PM grab a bnc connector and shave around 1-2mm off the insulator 07-Feb-20 10:32 PM it will still seal/mount against HV 07-Feb-20 10:32 PM I'll try that with the new bnc cable that arrives tomorrow 07-Feb-20 10:32 PM which probe is it? 07-Feb-20 10:32 PM the g1le? 07-Feb-20 10:34 PM Yeah 07-Feb-20 10:34 PM the four bolts should unscrew 07-Feb-20 10:34 PM Yeah 07-Feb-20 10:34 PM then you should be able to get the connector out 07-Feb-20 10:34 PM Do you have a datasheet for this probe? 07-Feb-20 10:34 PM nope 07-Feb-20 10:34 PM Damn 07-Feb-20 10:34 PM the probe also twists apart 07-Feb-20 10:34 PM that little seam is a thread 07-Feb-20 10:34 PM but I'm not sure if it will twist cables off 07-Feb-20 10:35 PM Ah 07-Feb-20 10:35 PM I'm also not sure if that seam is hermetic 07-Feb-20 10:35 PM as in, whether you'll expose the nai crystal to air if you undo it 07-Feb-20 10:35 PM The massive gasket at the back somewhat worries me 07-Feb-20 10:35 PM yeah I wouldn't remove it 07-Feb-20 10:35 PM the crystal might not be hermetic inside, and with this tiny of a crystal a puff of air means instant death for the probe 07-Feb-20 10:36 PM This is a scintillation based probe? 07-Feb-20 10:36 PM yes 07-Feb-20 10:36 PM there's a PMT coupled to a very thin NaI:Tl crystal behind an even thinner window 07-Feb-20 10:37 PM Neat, I thought it was still a breakdown one like a gm tube 07-Feb-20 10:37 PM specifically designed to capture very low energy gamma/xrays, but with the downside being that it's far worse than generic GM in terms of detecting higher energies 07-Feb-20 11:45 PM OK 07-Feb-20 11:45 PM have it down to Q10 or the tunnel diode being short 07-Feb-20 11:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B9041.png 07-Feb-20 11:46 PM A little trigger happy with schematic capture 07-Feb-20 11:46 PM But I appreciate it 07-Feb-20 11:46 PM Did you try kicad's spice integration? 07-Feb-20 11:46 PM I think you can go from that schematic to spice sim with a few clicks 07-Feb-20 11:46 PM If you want to replace it, AI301A should be a suitable replacement 07-Feb-20 11:46 PM cheap on ebay 07-Feb-20 11:46 PM http://welcolab.wixsite.com/discovery/1-tunnel-diodes-xref 07-Feb-20 11:46 PM This explains the unobtainium replacement 07-Feb-20 11:46 PM Thankfully 2N414 is a lot more available 07-Feb-20 11:53 PM yea its the tunnel diode I think... 07-Feb-20 11:53 PM :/ 07-Feb-20 11:53 PM You can buy the AI301A 07-Feb-20 11:53 PM See the page that details replacement of the tunnel diode with that 07-Feb-20 11:53 PM jeez 07-Feb-20 11:54 PM Just make sure it's not a cascade failure of something else 07-Feb-20 11:54 PM took it out of circuit and its a dead short 07-Feb-20 11:54 PM the transistor I suspected still seems fine 07-Feb-20 11:55 PM That's very dead 07-Feb-20 11:55 PM I may not need an exact replacment? I don't know what accuracy matters here in this circuit or if they just need that tunnel diode characteristic? 07-Feb-20 11:55 PM I think they need the characteristic 07-Feb-20 11:55 PM Can't hurt to try a more readily available alternative 07-Feb-20 11:55 PM I'd pick something with closer specs 08-Feb-20 12:07 AM hrm actually it may not necessarily be bad... 08-Feb-20 12:07 AM A high resistance reading on a DMM indicates that the diode is bad. A low resistance on a DMM and a low voltage on a diode tester are both normal when measuring a tunnel diode. 08-Feb-20 12:07 AM Got a curve tracer? :P 08-Feb-20 12:07 AM Sadly no... its something I've been meaning to buy forever 08-Feb-20 12:07 AM but have yet to bite the few hundred dollar to over a thousand dollar bullet 08-Feb-20 12:08 AM Well, buy the transistor first, it's cheaper and much closer 08-Feb-20 12:08 AM doesn't really check out to be bad though I don't think 08-Feb-20 12:09 AM https://www.ebay.com/itm/Power-Transistor-Curve-Tracer-adapter-XY-Oscilloscopes-NPN-PNP-Vce-10V/140547987228 08-Feb-20 12:09 AM Apparently this is a thing that exists 08-Feb-20 12:10 AM yea its a simple circuit you can build... 08-Feb-20 12:10 AM many people have done it 08-Feb-20 12:10 AM but since I plan to actually make my own transistors someday I want a nice featured curve tracer 08-Feb-20 12:10 AM they just go for lots of money 08-Feb-20 12:10 AM I have saved searches 08-Feb-20 12:12 AM tunnel diodes, problems... do I smell a dead model 12? :< 08-Feb-20 12:13 AM you can even see a dead model 12 when you scroll up 08-Feb-20 12:14 AM not sure if I can handle that 08-Feb-20 12:14 AM yea its an EARLY model 12 08-Feb-20 12:14 AM obviously 60s design, early 70s construction I think? 08-Feb-20 12:15 AM just like mine 08-Feb-20 12:15 AM I believe the S/N is 5593 08-Feb-20 12:15 AM stamped on the side of the top casting bottom right 08-Feb-20 12:15 AM when Ludlum was an itty bitty wittle company 08-Feb-20 12:16 AM they started in 1963 08-Feb-20 12:16 AM I think they were becoming something by the 70s, I just don't think the model 12 was released until the late 60s probably 08-Feb-20 12:16 AM or early 70s 08-Feb-20 12:16 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Ludlum_Model_12_70s-Mini-E9800.pdf 08-Feb-20 12:16 AM for some reason the first two pages are at the end 08-Feb-20 12:16 AM but I think this might help you 08-Feb-20 12:16 AM shakes fist 08-Feb-20 12:16 AM you mean I've spent the last hours drawing schematics for no reason 08-Feb-20 12:16 AM darn you~~~ lol 08-Feb-20 12:17 AM this is manual #3 08-Feb-20 12:17 AM well if you didn't live on the wrong timezone you could have started that when I was awake 08-Feb-20 12:17 AM yea yea... :/ 08-Feb-20 12:17 AM although eugh that resolution 08-Feb-20 12:17 AM hrm 08-Feb-20 12:18 AM next time just ask me 08-Feb-20 12:18 AM sure haha, figured youd just have what the internet had 08-Feb-20 12:18 AM but yea I am not sure if this tunnel diode is dead or not 08-Feb-20 12:18 AM I might have a higher rez version somewhere 08-Feb-20 12:18 AM but so far thats the closest part of the circuit where my pulse dies 08-Feb-20 12:19 AM https://drive.google.com/drive/folders/1G3smnSHuLt20_sZCi_jt_ywiPItlt2oB Well at least it's in color now 08-Feb-20 12:20 AM yea thats much clearer 08-Feb-20 12:20 AM although its missing some of the schematic hrm 08-Feb-20 12:20 AM er no nvm I am just stupid 08-Feb-20 12:22 AM ^^ 08-Feb-20 12:22 AM hah well looking through it yea I think I got most of the schematic on the nose, just not as pretty of layout hehe 08-Feb-20 01:22 AM well with a 47kohm resistor in where the tunnel was it counts and clicks again... of-course that won't be accurate due to the fact that it was using that tunnel diode to sharpen up the rising edge of the pulse to make integration of the pulses into the caps consistent for it to actually be accurate.... 08-Feb-20 01:22 AM but yea 08-Feb-20 01:25 AM eh, good enough 08-Feb-20 01:26 AM well it would be nice to have it calibrated again at some point 08-Feb-20 01:26 AM so I would like to get a tunnel diode back in there 08-Feb-20 01:26 AM its just a matter of if it has to be that exact tunnel diode or if just a similar one will work 08-Feb-20 01:27 AM I don't know if the diode is that critical 08-Feb-20 01:27 AM try calibrating it and see what happens 08-Feb-20 01:28 AM well... I mean I don't have the stuff to calibrate it and it has that weird gauge face on it at the moment 08-Feb-20 01:28 AM but, I do know simply a resistor there gets the transistor going but it won't be as consistent of a square wave as a tunnel diode would make it, they used one in there for a reason :) 08-Feb-20 01:28 AM I'll see if I can get another similarly rated tunnel diode 08-Feb-20 01:30 AM I just calibrated that gauge for DPM and ignored the 100 cm² 08-Feb-20 01:30 AM and calibrating it is really easy, just AC couple a negative pulse with some mV into the detector port 08-Feb-20 01:31 AM also, the other option... forget the tunnel diode... and modify it with a little micro and just have it count the pulses and do the integration on a micro and just put a little digital display where the gauge was :) 08-Feb-20 01:31 AM but ok thats a good idea hehe 08-Feb-20 01:45 AM You say that, but it's literally what the "scaler" meters with the little LCDs did 08-Feb-20 01:45 AM Just bolted logic onto it 08-Feb-20 01:46 AM well right, doing integration in the analog domain is precise for counting pulses, but digital its fairly simple so long as you have a good timebase which well having a RTC isn't hard or expensive 08-Feb-20 01:46 AM but even the precision of a timer on the chip is probably enough... 08-Feb-20 01:48 AM Don't need an RTC, internal rc oscs are good enough to do second-to-second counting within 0.00001 %whatever% 08-Feb-20 01:48 AM Of course not long term stable 08-Feb-20 01:48 AM right 08-Feb-20 02:10 AM hey 08-Feb-20 02:10 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-1ACE5.jpg 08-Feb-20 02:11 AM für ein strahlendes lächeln 08-Feb-20 02:11 AM ehehehe 08-Feb-20 02:11 AM strahl 08-Feb-20 03:27 AM Yay my standardized measurement geometry just arrived 08-Feb-20 03:27 AM still waiting on that lead tho... 08-Feb-20 03:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7F833.png 08-Feb-20 03:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8CDF2.png 08-Feb-20 03:27 AM but now I can start working on my activity standard 08-Feb-20 03:19 PM @__ice9 I contacted that custom quartz seller and ouch, wants $30ea for ID25*OD28+ID3*OD5 tube or $38ea for ID41*OD45+ID3*OD5 (the tube + capillary tip thing) with a MOQ of 10. Think the bridgman crystal growing stuff might have to wait for me to wrap up a few other projects. Going to see about getting another quote before totally putting it on the back burner 08-Feb-20 04:03 PM <__ice9#6039> Hmm. That MOQ is a little weird. My super nice flask was only about $100 08-Feb-20 04:03 PM <__ice9#6039> Well if you have an oxyfuel torch I guess you can just buy a cheap quartz tube on eBay and try to work it to a twisted closure in the center and pull apart 08-Feb-20 04:03 PM <__ice9#6039> Quartz is so much hotter to work than boro though 08-Feb-20 04:03 PM <__ice9#6039> A normal torch won't even soften it 08-Feb-20 04:03 PM <__ice9#6039> Needs oxyfuel and patience 08-Feb-20 04:05 PM yep lots and lots of heat 08-Feb-20 04:05 PM not something i would really feel comfortable with being able to get right but maybe i could make some molds out of hard graphite on the mill 08-Feb-20 04:05 PM <__ice9#6039> On the bright side the thermal CoE is off-the-charts minuscule, so it's pretty easy to avoid breaking it 08-Feb-20 04:05 PM and then do the sorta glass blowing thing 08-Feb-20 04:05 PM not sure if quartz will move as glass does 08-Feb-20 04:06 PM <__ice9#6039> Yeah graphite and high alumina brick insulation will help keep it from losing heat as rapidly 08-Feb-20 04:06 PM <__ice9#6039> I have no idea whether it can be blown. That sounds a bit crazy but it might work if it's incredibly hot 08-Feb-20 04:07 PM sorta doubt it is manufactured by another process but i only looked a little bit 08-Feb-20 04:07 PM <__ice9#6039> I think it's probably easier to just start with a pretty wide tube and a circular oxy burner in the middle, heat it bright white hot, and slowly twist with a jig 08-Feb-20 04:08 PM that could work too...squishing down the bottom of the tube or something into the capillary structure 08-Feb-20 04:09 PM <__ice9#6039> I am genuinely not convinced that it needs to be vacuum sealed 08-Feb-20 04:09 PM <__ice9#6039> If you argon shield 08-Feb-20 04:09 PM <__ice9#6039> But I understand if you want to try it 08-Feb-20 04:09 PM <__ice9#6039> It will be a lot harder than just making an open-top quartz vessel 08-Feb-20 04:09 PM i want to try it both ways if i manage to wrap up some of my other stuff first so that i can properly consider a project of that depth 08-Feb-20 04:09 PM would be a nice excuse to buy some proper chem glassware finally 08-Feb-20 04:10 PM <__ice9#6039> (if you look hard enough, you may even be able to find a closed-end quartz tube for aquarium UV lights) 08-Feb-20 04:10 PM the time/frustration factor on making the tribromides seemed strongly in favor of making them myself after the napkin math 08-Feb-20 04:10 PM <__ice9#6039> deschem and nanshing glass on eBay are great for 24/40 stuff 08-Feb-20 04:12 PM the tribromides do not seem terribly challenging to make 08-Feb-20 04:12 PM it seems like you can just react the La2O3 or CeO2 with HBr and you get the tribromide hydrates 08-Feb-20 04:48 PM <__ice9#6039> Yep that sounds right 08-Feb-20 04:48 PM <__ice9#6039> HBr is very easy to make too -- just H2SO4 and NaBr distilled into water 08-Feb-20 05:00 PM might be harder than i was realizing but still doable for the LaBr3 https://sci-hub.se/10.1016/0022-5088(87)90372-9 08-Feb-20 05:00 PM just it says not to use CeO2? might have to find a different route on that one 08-Feb-20 05:06 PM <__ice9#6039> There are other cerium oxides 08-Feb-20 05:06 PM <__ice9#6039> Maybe it just meant to avoid the +4 version 09-Feb-20 05:23 AM @Treehouseman you can be sloppy and mash BNC onto MHV sometimes, depending on connector tolerance (an old L-connector or ancient coupler can work gr8 here ime) and also on voltage.. i'd get nervous above 1.5-2kV, depending. if you do get inside it, SHV can be a lot cheaper/nicer to replace it with; i've kinda gotten in the habit of replacing stuff to it on old gear, when feasible 09-Feb-20 05:23 AM er @Treehouseman ^ 09-Feb-20 12:10 PM <__ice9#6039> Also prefer SHV fwiw, just a better designed connector for the job in general. Don't exceed 5kV AC or so though. 09-Feb-20 12:10 PM <__ice9#6039> For higher voltage plastic bayonet connectors are needed. 09-Feb-20 12:10 PM <__ice9#6039> For x-ray/sparkplug voltages, dielectric grease is also desirable in the bayonet connector 09-Feb-20 12:55 PM The cable I ordered fits reliably out of the box, I'll modify it a little to make it easier to get on there but it should do for now 09-Feb-20 10:26 PM probably a stupid question but would one of these work as a power supply to run a He3 tube? i was looking in a box and found one of these that i sorta forgot i had... https://www.ebay.com/itm/383310966683 09-Feb-20 10:26 PM would still need the rest of the stuff necessary to run things but that would be one thing off the list 09-Feb-20 10:28 PM <__ice9#6039> Not stable at all 09-Feb-20 10:28 PM <__ice9#6039> Those things are terrible in quality 09-Feb-20 10:28 PM <__ice9#6039> One of them even shocked me through its own power lead once and killed the PSU 09-Feb-20 10:28 PM yep, i do not even remember why i got it originally but was hoping to give it some life, guess it goes back in the box 09-Feb-20 10:29 PM <__ice9#6039> Use it as an ionizer. Ionizers are useful. 09-Feb-20 10:29 PM <__ice9#6039> I should note that the other idk 5 of them I have did not fail in that manner lol 09-Feb-20 10:29 PM <__ice9#6039> But they are not at all stable HV bias sources 09-Feb-20 10:41 PM i wish NIM gear was less expensive 09-Feb-20 10:41 PM would be nice to get a little rack and stuff but the prices are a bit hard to justify 09-Feb-20 10:44 PM <__ice9#6039> What voltage do you need for your tube? 09-Feb-20 10:44 PM <__ice9#6039> Also negative or positive? 09-Feb-20 10:47 PM ive got two i realized, forgot i had added on a couple things after customs ate my first package... have a SI19N and SMN-17 both need positive bias as far as i know 09-Feb-20 10:47 PM the SI19N around 2200-2500V and SMN-17 1500-1900V 09-Feb-20 10:51 PM <__ice9#6039> Hmm that's a bit high for the simpler circuits I know of. 09-Feb-20 10:51 PM <__ice9#6039> Could maybe stack two of them 09-Feb-20 10:52 PM that is why they have been sitting in a bin for so long that i forgot i had two heh 09-Feb-20 10:52 PM <__ice9#6039> Lol 09-Feb-20 10:54 PM was thinking of picking up one of the NIM 0-5kV power supplies and then just running the +-24V to it instead of a proper rack but that still leaves the rest of the circuits necessary to actually use it to figure out 09-Feb-20 10:54 PM <__ice9#6039> http://www.techlib.com/science/geiger.html These ones might not actually be precise enough for a gas proportional counter either hmm. I used one for a Russian alpha counter tube. 09-Feb-20 10:54 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1581317630636-D407A.png 09-Feb-20 10:54 PM <__ice9#6039> That would be regulated better yes. 09-Feb-20 10:54 PM <__ice9#6039> Precise regulation of HV PSUs is a somewhat annoying process 09-Feb-20 10:54 PM <__ice9#6039> Better bought than made if possible 09-Feb-20 11:13 PM <__ice9#6039> @Mason_Yu apparently x-ray or gamma ray photons can be converted into neutron beams via deuterium or beryllium targets as well-- although the example figures reported here do not look especially high 09-Feb-20 11:13 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200210-010945-FCB6C.png 09-Feb-20 11:13 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200210-010959-9BE1E.png 09-Feb-20 11:14 PM Oh yeah, that's how the electron LINAC neutron source at my school works 09-Feb-20 11:14 PM Shoot electron beam into molybdenum target, get loads of bremsstrahlung photons and then produce photoneutrons 09-Feb-20 11:15 PM <__ice9#6039> What voltage/current and what resulting neutron flux? 09-Feb-20 11:15 PM <__ice9#6039> I was also intrigued that heavy water is apparently an acceptable target material 09-Feb-20 11:18 PM The accelerator is driven by 9 L-band RF cavities, with maximum electron energy at ~60MeV and peak current of 3A. The resulting neutron flux is pretty much isotropic, maximum of ~4*10^13 neutrons per second 09-Feb-20 11:18 PM Well for photoneutron production any photons capable of exceeding the threshold energy will do it, the target material just changes that threshold 09-Feb-20 11:18 PM Heavy water happens to have one of the highest threshold energies, thus you get fast neutrons 09-Feb-20 11:22 PM <__ice9#6039> Ah I see -- that's a lot of neutrons, but not very power efficient, and quite enormous 09-Feb-20 11:23 PM Oops, I messed up there, you DON'T get a lot of fast neutrons because of the high threshold, most of the gamma energy would be going to overcoming the nuclear binding energy 09-Feb-20 11:23 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200210-012009-52248.png 09-Feb-20 11:23 PM <__ice9#6039> Photodisintegration threshold energy (apparently this is indeed just the binding energy, on further reading) is very low for deuterium 09-Feb-20 11:26 PM Oh interesting, yeah I guess there are a few special cases for low Z targets, which is why they are interesting I suppose 09-Feb-20 11:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4918F.png 09-Feb-20 11:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-27E8C.png 09-Feb-20 11:26 PM A LINAC is quite enormous indeed, but LINAC tech is from the 50s and it still works like a charm! They are upgrading it soon and it should produce around an order of magnitude more neutrons a couple of years down the road? 09-Feb-20 11:28 PM <__ice9#6039> From what I understand here, it looks very much like a tunable flash x-ray tube in the vicinity of 2.3-2.7MeV could also do this in one shot...? 09-Feb-20 11:28 PM <__ice9#6039> As in, without additional accelerator stages 09-Feb-20 11:29 PM There are quite a few differences between gamma source driven photoneutron sources and accelerator/high energy x-ray driven photoneutron sources 09-Feb-20 11:29 PM <__ice9#6039> ... a photon is a photon, yes? 09-Feb-20 11:30 PM One is usually monoenergetic, the other is a bremsstrahlung spectrum 09-Feb-20 11:30 PM And then there's the target design problem 09-Feb-20 11:31 PM <__ice9#6039> Well yes, I am only speaking of the portion of the spectrum beyond the necessary energy 09-Feb-20 11:31 PM <__ice9#6039> Hmm about target design? 09-Feb-20 11:31 PM <__ice9#6039> Tbf 2MeV photons will overpenetrate a beryllium target to a ridiculous extent 09-Feb-20 11:31 PM <__ice9#6039> Heavy water isn't much better either 09-Feb-20 11:33 PM You need to cool the target at higher powers, and there's also the issue of making sure most of the bremsstrahlung photons effectively interacts in the target 09-Feb-20 11:33 PM Yeah exactly 09-Feb-20 11:33 PM <__ice9#6039> Would need a long tube of it 09-Feb-20 11:33 PM <__ice9#6039> Large volumes of heavy water begin to become costly enough that it probably makes more sense to just accelerate deuterium into deuterium as discussed above instead, I guess 09-Feb-20 11:36 PM Increasing the size doesn't simply solve the problem either 09-Feb-20 11:36 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B1362.png 09-Feb-20 11:38 PM <__ice9#6039> Yeah due to earlier interactions, had wondered about that.... 09-Feb-20 11:38 PM <__ice9#6039> So the vast majority of beam energy gets wasted 09-Feb-20 11:38 PM <__ice9#6039> Whether by failing to meet the threshold or missing the target nucleons or rebounding ineffectually around several instead of striking one strongly enough to dislodge the neutron 09-Feb-20 11:38 PM <__ice9#6039> I see. This makes more sense now. 09-Feb-20 11:43 PM I'm not sure if you can drive this effectively with a (really high energy) x-ray source. There's so much energy wasted in sub-threshold characteristic peaks and the bremsstrahlung tail, and also from transporting the photons to the neutron producing target 09-Feb-20 11:43 PM Even if you can, the x-ray machine will be so enormous and expensive, you might as well build a electron LINAC 10-Feb-20 05:03 AM <__ice9#6039> Flash x-ray can do a few MeV from something as simple as a large Marx generator, but yes the efficiency is clearly quite awful. 10-Feb-20 05:03 AM <__ice9#6039> D-D BoT is superior. I don't have the free time to pursue something like this atm given the level of complexity involved, but I think the conclusion is nonetheless useful for the time being. 10-Feb-20 05:03 AM <__ice9#6039> D-T remains explicitly regulatorily inaccessible and D-Li6D is likely implicitly so at the very least. 10-Feb-20 05:13 AM I found a perfect use for lead bricks 10-Feb-20 05:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200210_141114-0A2AD.jpg 10-Feb-20 05:05 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200210_200455-F8DA0.jpg 10-Feb-20 05:05 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200210_200509-925B5.jpg 10-Feb-20 05:05 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200210_200530-F0FCD.jpg 10-Feb-20 07:00 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/JPEG_20200210_215951-92FFB.jpg 10-Feb-20 07:00 PM Same radium card 10-Feb-20 07:04 PM Let me flip mine to dosage and see how it compares 10-Feb-20 07:06 PM I don't think it will give you an accurate dose rate 10-Feb-20 07:07 PM 62.1mR/h 10-Feb-20 07:10 PM that sounds roughly correct, accounting for low energies 10-Feb-20 07:10 PM but you can't measure beta and alpha in siverts/rontgens/whatever 10-Feb-20 07:13 PM So your card also has 0.03 microgram of radium on it right? 10-Feb-20 07:15 PM My GMC-300 reads 3800CPM 19uSv/h 10-Feb-20 07:15 PM Yes, 0.03 micrograms 10-Feb-20 07:16 PM That's 0.03 uCi of radium, and a quick calculation on rad pro calculator tells me that it should give <1 mR/hr dose rate at half a centimeter away (~the closest I can get my ion chamber to it) 10-Feb-20 07:16 PM http://www.radprocalculator.com/Gamma.aspx 10-Feb-20 07:16 PM Any chance that your meter is assuming the gamma energies? Like equivalent to Co-60 and so on? 10-Feb-20 07:17 PM Honestly no idea, I can't find info on this meter 10-Feb-20 07:17 PM it's a G1LE probe 10-Feb-20 07:18 PM I can't think of a better way to calibrate dose rate than using an actual free air ionization chamber 10-Feb-20 07:18 PM It's a Dosimeter 3100 Survey Meter 10-Feb-20 07:18 PM Generic Device Name 3100 10-Feb-20 07:18 PM Mine was calibrated early 2018, so it is technically out of cal now 10-Feb-20 07:18 PM Dosimeter is the brand 10-Feb-20 07:18 PM Company is the manufacturer 10-Feb-20 07:18 PM Produced at the Plant 10-Feb-20 07:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200210_221905-BC0F2.jpg 10-Feb-20 07:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200210_221911-A52B1.jpg 10-Feb-20 07:19 PM I was wrong, it is even more generic. 10-Feb-20 07:19 PM Dosimeter, produced by the Dosimeter Corporation, in Country, assembled by Person. 10-Feb-20 07:19 PM They've never had a website, says a 1998 book. 10-Feb-20 07:19 PM Dosimeter Corporation of America, 5 Eastmans Road, Parsippany, NJ 07054 10-Feb-20 07:19 PM (was) 10-Feb-20 07:22 PM Pretty sure that thing has to be making some sort of equivalent dose rate conversion from count rate with a source assumption in mind 10-Feb-20 07:25 PM I plan on dumming the memory at some point so I can see what it's doing 10-Feb-20 07:25 PM because I have no data other than what's on the bottom cover 10-Feb-20 07:27 PM Hmm, okay, I'll actually bring my ion chamber to calibrate against a NIST traceable one on a Co-60 source sometime this month. 10-Feb-20 07:27 PM Should cover even this very low dose rate 10-Feb-20 07:27 PM are ion chambers calibrated against Co60? 10-Feb-20 07:28 PM in the end I mainly just have my meters for playing around with and for use with my xray machine 10-Feb-20 07:28 PM That's one way to do it, the only way accessible to me at the moment, will give me an idea at least 10-Feb-20 07:28 PM This is not going to be a full calibration 10-Feb-20 07:28 PM i know Cs137 is used very often for calibrating GM counters; i see Co60 specified for HPGe detectors on occasion too 10-Feb-20 07:30 PM https://www.nist.gov/system/files/documents/calibrations/sp250-40.pdf 10-Feb-20 07:30 PM Cs137 with Co60 makes a nice three point calibration 10-Feb-20 07:30 PM This is essentially what I'm planning to do. 10-Feb-20 07:30 PM oh interesting 10-Feb-20 07:31 PM Well, gotta have the Cs137 source with high enough activity first! It's not impossible for me to do, will be hard though 10-Feb-20 07:51 PM this paper is exhilarating omg 10-Feb-20 07:51 PM Every NIST paper is 10-Feb-20 07:51 PM Oh this thing actually comes with its own calibration software 10-Feb-20 07:51 PM Neat! 10-Feb-20 07:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3CB12.png 10-Feb-20 07:57 PM oh cool :o 10-Feb-20 07:57 PM Clearly state of the art 10-Feb-20 07:57 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6CD8D.png 10-Feb-20 07:58 PM I am in love with this software 11-Feb-20 10:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200211_191614-3340C.jpg 11-Feb-20 10:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200211_191625-BF001.jpg 11-Feb-20 10:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200211_191639-9D6ED.jpg 11-Feb-20 10:20 AM giiiiant preamp! 11-Feb-20 10:20 AM guessing it's made for proportional detectors 11-Feb-20 10:20 AM teardown will follow once I'm home 11-Feb-20 10:33 AM ohhh hehe neat! 11-Feb-20 10:52 AM thats a beefy preamp 11-Feb-20 10:59 AM ooo 11-Feb-20 10:59 AM No idea if this is functional or not but the seller said they would drop it down to $700. To much for me to risk (and it is too far away from everyone I know in Texas) but maybe someone has deeper pockets than me: https://www.ebay.com/itm/Nitrogen-Tank-with-Ortec-GLP-10180-07P-low-energy-HPGe-scintillation-detector/173250383775 11-Feb-20 10:59 AM i like the 'only the amp power pins we ABSOLUTELY need' 11-Feb-20 10:59 AM https://i.ebayimg.com/images/g/3GMAAOSwAPpeObDX/s-l1600.jpg 11-Feb-20 11:00 AM nim-style economical 11-Feb-20 11:00 AM photo of the window from the seller 11-Feb-20 11:00 AM if i had a drive to texas in me i'd have already grabbed that tbh 11-Feb-20 11:01 AM yeah it is just a 3hr drive each way for literally everyone i know in texas 11-Feb-20 11:01 AM if he was willing to go down to like $200 i would probably have hopped in my car and been on the road though 11-Feb-20 11:01 AM i wish all the NIM racks on ebay were not ridiculous prices with $50 or more shipping costs... you would think that kinda stuff would not be so expensive with how much of it there is out there 11-Feb-20 11:15 AM my working theory is that people who know to call it 'NIM' know its worthwhile 11-Feb-20 11:15 AM a NIM bin with a power supply with test points that read around where they're s'posed to is a rock-solid set of bipolar linear power supplies that're likely to keep on hauling for eons, barring maybe a round of capacitor replacements 11-Feb-20 11:15 AM trick is to see if you can find someone who doesn't know what it is and is just looking to sell off some weird 5U test equipment frame, i'd wager.. 11-Feb-20 11:20 AM thats a good point...maybe i should just search for equipment racks or something 11-Feb-20 11:21 AM i got mine at the electronics swap meet (which i CANNOT wait for it to start back up) from a dude along with a pile of bespoke modules from some Berkeley auction, most likely.. very appreciable 'if you know what this is for, i'll trust your judgement on its worth' attitude that seems functionally nonexistent on ebay 11-Feb-20 11:21 AM i already need another one tho >_> 11-Feb-20 11:22 AM do not think there are any electronic swap meets here besides the HAM radio guys and when i went to that they were all crazy prices heh 11-Feb-20 11:22 AM afraid i might start getting into CAMAC soon too, for computerized data acquisition 11-Feb-20 11:22 AM idk how to do that on the cheap 11-Feb-20 11:22 AM ouch 11-Feb-20 11:28 AM in other news 11-Feb-20 11:28 AM i just got a bunch of lead >_> 11-Feb-20 11:28 AM fun fun fun, dont drop it on your toes 11-Feb-20 11:29 AM that's the plan :D 11-Feb-20 11:29 AM i get to learn how to work a lift gate 11-Feb-20 11:31 AM in my limited experience it is very easy, 3 buttons and not a lot to mess up 11-Feb-20 11:36 AM Challenge Accepted 11-Feb-20 11:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200211_203731-DAAD1.jpg 11-Feb-20 11:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200211_203744-6B29D.jpg 11-Feb-20 11:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200211_203824-374A8.jpg 11-Feb-20 11:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200211_203855-006F7.jpg 11-Feb-20 11:59 AM ooo 11-Feb-20 11:59 AM spacious 11-Feb-20 12:00 PM and pretty! 11-Feb-20 12:05 PM wonder if we should start a database of FETs We Have Known And Loved -- get some lists going of any weird unobtanium instrumentation/electrometer-grade FETs we find in our preamp travels 11-Feb-20 12:05 PM iirc that was an issue you had with your HP 10615A, right? 11-Feb-20 12:05 PM or whatever the other model # is 11-Feb-20 12:06 PM hp 5554a, but yes ^^ 11-Feb-20 12:06 PM ah yea 11-Feb-20 12:06 PM but by then I figured out that it really doesn't matter 11-Feb-20 12:06 PM oh? 11-Feb-20 12:06 PM any jfet in a metal can will do just fine 11-Feb-20 12:06 PM interesting 11-Feb-20 12:07 PM carl willis threw some audio jfet in TO92 in his HPGe and got 1.7 keV FWHM 11-Feb-20 12:07 PM omg 11-Feb-20 12:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/hpge_transistors-45B30.png 11-Feb-20 12:07 PM kinds hurts to look at but yeah 11-Feb-20 12:07 PM is that.. on the cold side? o.O 11-Feb-20 12:07 PM yep 11-Feb-20 12:07 PM lmao 11-Feb-20 12:07 PM incredible 11-Feb-20 12:08 PM https://carlwillis.wordpress.com/2011/09/16/hpge-detector-part-i-repair/ 11-Feb-20 12:09 PM hehehe 11-Feb-20 12:11 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-11995.png 11-Feb-20 12:11 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E0FED.png 11-Feb-20 12:11 PM someoneTM just ordered me to post this 11-Feb-20 12:12 PM A modern microfocus head 11-Feb-20 12:12 PM EVERYONE HAS MICROFOCUS HEADS 11-Feb-20 12:12 PM runs around screaming 11-Feb-20 12:12 PM though i will stop here, cancer is not really my thing 11-Feb-20 12:12 PM hehe 11-Feb-20 12:12 PM i finally got the tube from mikeselectricstuff 11-Feb-20 12:13 PM I vaguely remember, was yours dead? 11-Feb-20 12:13 PM he found it and i swapped it for a pill cam from marcoreps that found its way to me 11-Feb-20 12:13 PM yes, it was dropped (at least once by me) and the anode desided it wanted a divorce from the rest of the tube 11-Feb-20 12:13 PM The natural nerd cycle 11-Feb-20 12:13 PM You'll love this 11-Feb-20 12:13 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200204_220320-839AA.jpg 11-Feb-20 12:13 PM You're looking at $1200 of non-refundable disappointment 11-Feb-20 12:15 PM aaaw crap.... 11-Feb-20 12:15 PM Yyyup. 11-Feb-20 12:15 PM I bought another one, hoping it slips through customs again. 11-Feb-20 12:16 PM i still dont have a sensor/software 11-Feb-20 12:16 PM I have a spare dental sensor but it's semi-dead and I think it needs one or two bond wires repaired 11-Feb-20 12:16 PM Outputs an image but it's an image of the ADC dangling freely in the air 11-Feb-20 12:16 PM it will be just 1200$... 11-Feb-20 12:16 PM hehe 11-Feb-20 12:17 PM heh 11-Feb-20 12:17 PM mine is an rvg6100 11-Feb-20 12:17 PM It's a dental sensor, they can be had for $1200 new 11-Feb-20 12:17 PM in case you know someone with software 11-Feb-20 12:17 PM yes, mine is as well 11-Feb-20 12:17 PM 1200 used 11-Feb-20 12:17 PM my dad just mooved his dentists office and bought stuff from other doctors giving up their profession 11-Feb-20 12:18 PM https://www.carestreamdental.com/en-gb/training-resources/drivers-and-updates/ 11-Feb-20 12:18 PM you can get it from carestream directly 11-Feb-20 12:18 PM like wholesale buying everything at once so i got it sort of for free 11-Feb-20 12:18 PM the drivers 11-Feb-20 12:18 PM not the software to control it 11-Feb-20 12:19 PM it should be there too 11-Feb-20 12:19 PM twain driver 11-Feb-20 12:19 PM http://origin-qps.onstreammedia.com/origin/CarestreamHealthInc/Drivers/SetupRVG-Carestream_4.6.9.0-C.zip 11-Feb-20 12:19 PM a tiny 320mb 11-Feb-20 12:20 PM oh 11-Feb-20 12:20 PM twain will run such sensors? O.o 11-Feb-20 12:20 PM yes 11-Feb-20 12:21 PM dammn.... 11-Feb-20 12:21 PM thank you very much already worth coming back here once in a while 11-Feb-20 12:21 PM will try later 11-Feb-20 12:21 PM though i think i will have to build some sort of shutter before using it, the microfocus nees a few minutes warmup and seconds to build up voltage 11-Feb-20 12:21 PM not really useful for exposing such stuff 11-Feb-20 12:22 PM it should have a gate 11-Feb-20 12:22 PM i dont have a pinout 11-Feb-20 12:22 PM also it behaves very strange 11-Feb-20 12:22 PM @TecKonstantin might know 11-Feb-20 12:22 PM he's the x-ray pinout guru 11-Feb-20 12:22 PM PXS5, right? 11-Feb-20 12:23 PM by the way the HV part is cracking building up voltage i doubt its made for cycling the high voltage 11-Feb-20 12:23 PM that sounds like missing oil 11-Feb-20 12:23 PM right 11-Feb-20 12:23 PM also rght 11-Feb-20 12:23 PM i culd not fill it perfectly 11-Feb-20 12:23 PM so im operating it vertically only 11-Feb-20 12:23 PM I have some spare oil... $120/gram, I have about 10 grams :P 11-Feb-20 12:23 PM /s 11-Feb-20 12:24 PM xD 11-Feb-20 12:24 PM i have saved the oil but there is plenty alternatives 11-Feb-20 12:24 PM the problem is the construction 11-Feb-20 12:24 PM yeah you can fill with fluorinert or other stuff 11-Feb-20 12:24 PM how do you remoove all the air? 11-Feb-20 12:24 PM vacuum 11-Feb-20 12:24 PM and where is the expansion space then? 11-Feb-20 12:24 PM no vacuum 11-Feb-20 12:24 PM should be a baffle somewhere 11-Feb-20 12:24 PM no way to get vacuum in there 11-Feb-20 12:24 PM nop 11-Feb-20 12:24 PM nothing anywhere 11-Feb-20 12:25 PM internally likely 11-Feb-20 12:25 PM internal is potted 11-Feb-20 12:25 PM There's a baffle deep inside mine from what I can tell 11-Feb-20 12:25 PM but I don't see it from the oil side 11-Feb-20 12:26 PM i even checked the screw holes holding the tube in place and considered drilling towards the chamber 11-Feb-20 12:26 PM use some mirrors and make it x-ray itself 11-Feb-20 12:26 PM in your case at least there is some aluminium tube to be drilled into, in mine there is absolutely no way 11-Feb-20 12:26 PM I think I know how it's done 11-Feb-20 12:26 PM You remove all the oil, then you get a loooooooong syringe 11-Feb-20 12:26 PM And slowly fill it from the bottom 11-Feb-20 12:27 PM use some mirrors and make it x-ray itself @GigaSquirrel nice of you to label your thoughts validity yourself 11-Feb-20 12:27 PM So that the oil squeezes the air out as it fills 11-Feb-20 12:27 PM nah, thats not really the problem 11-Feb-20 12:27 PM the anode side has a cup shape to it 11-Feb-20 12:27 PM you cant insert it without trapping air 11-Feb-20 12:27 PM Get that syringe in there 11-Feb-20 12:27 PM and how do i get the syringe out afterwards? 11-Feb-20 12:27 PM it will have to be hook shaped 11-Feb-20 12:28 PM pull it out 11-Feb-20 12:28 PM just a thin plastic tube you can curl 11-Feb-20 12:28 PM But if there really is no baffle, you really don't want to fully fill it with oil. 11-Feb-20 12:28 PM because the moment it gets a couple degrees warmer, pop 11-Feb-20 12:28 PM exactly 11-Feb-20 12:28 PM thats why i asked you for the expansion space 11-Feb-20 12:28 PM i will most likely make some sort of spacer ring in two pieces 11-Feb-20 12:29 PM email thermo and ask them inconspicuously if this specific head has an oil expansion baffle 11-Feb-20 12:29 PM har har 11-Feb-20 12:29 PM maybe even just a very thick o-ring that can be pierced by a syringe 11-Feb-20 12:29 PM then blt the tube down slightly and evacuate via the syringe 11-Feb-20 12:29 PM then cut the o-ring off 11-Feb-20 12:29 PM and insert the tube fully displacing some more oil 11-Feb-20 12:30 PM I've had a few crazy concepts on developing my own microfocus tube 11-Feb-20 12:30 PM jup, i doubt they will answer anything sadly... 11-Feb-20 12:30 PM It's been a hot topic of brainstorming between me and ice9 for the last few days here 11-Feb-20 12:30 PM Mostly because avoiding beryllium turns out to be incredibly hard 11-Feb-20 12:31 PM well,you have an electron gun and an in tact window 11-Feb-20 12:31 PM intact? 11-Feb-20 12:31 PM about that... 11-Feb-20 12:31 PM i actually considered just dropping my broken tube in a chamber with a tmp 11-Feb-20 12:31 PM when I opened the package, oil was dripping through the beryllium window. 11-Feb-20 12:32 PM ouff 11-Feb-20 12:32 PM I can probably reuse parts of the window, but there's an obvious big crack in it 11-Feb-20 12:32 PM mh better dont... 11-Feb-20 12:32 PM the electron gun is also thoroughly soaked in oil 11-Feb-20 12:32 PM why beryllium anyways? 11-Feb-20 12:32 PM low energy and conductivity 11-Feb-20 12:32 PM https://discordapp.com/channels/513115950501855256/513115950501855261/676619271400587264 11-Feb-20 12:32 PM See this 11-Feb-20 12:33 PM yes of cause 11-Feb-20 12:33 PM but why go so low in energy? 11-Feb-20 12:33 PM in my applications i have an Al filter on it anyways 11-Feb-20 12:33 PM well, you'd want at least around 20kv 11-Feb-20 12:33 PM no other material can really pass that easily 11-Feb-20 12:33 PM plus the issue is not so much passing the energies, but not generating the x-rays 11-Feb-20 12:33 PM https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0156224&type=printable 11-Feb-20 12:33 PM see this paper 11-Feb-20 12:36 PM aaaahh ok that makes sense 11-Feb-20 12:36 PM CVD diamond is basically impossible at home 11-Feb-20 12:36 PM if we can solve that issue, the rest is doable-ish 11-Feb-20 12:36 PM I will also replace the filament with a carbon nanotube cold cathode gated emitter 11-Feb-20 12:36 PM because: a) the added complexity is absolutely minimal b) it's cheap c) it'll last absolutely forever 11-Feb-20 12:37 PM nice 11-Feb-20 12:37 PM point is, ultra high end microfocus x-rays for everyone! 11-Feb-20 12:37 PM at a very affordable price 11-Feb-20 12:38 PM jup 11-Feb-20 12:38 PM gofundme.com/kickstarter/indiegogo 11-Feb-20 12:38 PM im also still interested in the other end of the spectrum 11-Feb-20 12:38 PM low energy, high power, bad focus 11-Feb-20 12:38 PM sterilization beam 11-Feb-20 12:39 PM with this idea it can easily be readapted 11-Feb-20 12:39 PM multi kW 20keV r so 11-Feb-20 12:39 PM replace the microfocus target with a solid chunk of water-cooled copper and you can stuff kilowatts through it 11-Feb-20 12:39 PM but not at 20kev, closer to 40-60 11-Feb-20 12:40 PM well, i need 20 11-Feb-20 12:40 PM need? 11-Feb-20 12:40 PM why so low? 11-Feb-20 12:40 PM so shielding is easy and absorption in organic material is optimal 11-Feb-20 12:40 PM shielding for 60kev is easy 11-Feb-20 12:40 PM according to @GigaSquirrel 20keV will result in 30mm water absorbing all 11-Feb-20 12:40 PM wich is perfect for petri dishes 11-Feb-20 12:40 PM ("all") 11-Feb-20 12:41 PM blame it on the others 11-Feb-20 12:41 PM so more will actually be a problem 11-Feb-20 12:41 PM at 50kev the half value layer for lead is 0.06mm 11-Feb-20 12:41 PM 20 keV photons in water have a half value layer of 8.5 mm 11-Feb-20 12:41 PM even not considering shielding 11-Feb-20 12:41 PM allright, even better 11-Feb-20 12:41 PM memorizing numbers... 11-Feb-20 12:41 PM 0.06mm to get 50% at 50kev 11-Feb-20 12:41 PM yes 11-Feb-20 12:42 PM electrons have their bragg peak at 8.5 µm in water 11-Feb-20 12:42 PM so you only need what, 10 HVLs to get basically 0 11-Feb-20 12:42 PM as said, i want them to be absorbed as fast as possible 11-Feb-20 12:42 PM in water, not metal 11-Feb-20 12:42 PM 1mm of lead will be over 16 HVLs 11-Feb-20 12:42 PM essentially 100% absorption 11-Feb-20 12:42 PM I don't see why you want water for this 11-Feb-20 12:42 PM it's harder to contain and shape 11-Feb-20 12:44 PM because how often do you want to sterilize water based stuff vs lead based stuff 11-Feb-20 12:44 PM xD 11-Feb-20 12:44 PM well you don't care about absorption in organics 11-Feb-20 12:44 PM if it goes through, it goes through 11-Feb-20 12:44 PM but i dont want it to do that 11-Feb-20 12:45 PM at these power levels, sieverts per minute, it will sterilize absolutely everything eventually 11-Feb-20 12:45 PM if there is dna in the way i want it to absorb as much as it can 11-Feb-20 12:45 PM eventually 11-Feb-20 12:45 PM eventually = minutes 11-Feb-20 12:45 PM but if i can have a factor of 5 better, why not? 11-Feb-20 12:45 PM because you can't have a 20kev 2kw tube 11-Feb-20 12:45 PM (unless you go super exotic) 11-Feb-20 12:45 PM (I charge 2000% extra to work with beryllium) 11-Feb-20 12:46 PM 20kev should work with simple aluminium foil 11-Feb-20 12:46 PM not without serious absorption 11-Feb-20 12:46 PM and it'd have to be quite thin even then 11-Feb-20 12:46 PM 20kev is 100% beryllium territory 11-Feb-20 12:46 PM what's your anode material going to be to get a 20keV peak? or are you just going to use low-voltage continuum radiation down there? 11-Feb-20 12:46 PM <__ice9#6039> @Spirit trapped small air bubbles in these oil filled HV heads are not usually causes of arc faults except inside the transformer. Vacuum soaking those is worthwhile. 11-Feb-20 12:47 PM 20 keV photons have a hvl of 750 µm in Al... 11-Feb-20 12:47 PM low voltage continuum @qualia 11-Feb-20 12:47 PM 14u is normal foil and will withstand the pressure at 2mm diameter 11-Feb-20 12:47 PM *20mm 11-Feb-20 12:47 PM and will be perfectly not permeable to vacuum? 11-Feb-20 12:47 PM <__ice9#6039> @Spirit you can pass 20kV through thin aluminum pretty easily actually 11-Feb-20 12:48 PM i suspect beryllium is used for systems without a pump because it can be thick enough to be mechanically stable enough 11-Feb-20 12:48 PM it's also guaranteed to be not vacuum permeable 11-Feb-20 12:48 PM yes, non permeable as faar as a turbo pump is considered 11-Feb-20 12:48 PM (because that's just the only type they make for this application) 11-Feb-20 12:49 PM i have several broken CF40 viewports and a 30kV powersupply here 11-Feb-20 12:49 PM sooo 11-Feb-20 12:49 PM if im bored i will try 11-Feb-20 12:49 PM if you want a continuously pumped tube, it gets a lot easier 11-Feb-20 12:49 PM why not just... 0.1mm Al? 11-Feb-20 12:49 PM <__ice9#6039> 10kV is harder though. 11-Feb-20 12:49 PM @GigaSquirrel because you still eat a huge amount of x-rays 11-Feb-20 12:49 PM that's stable enough, that's non-permeable and will only eat like 15% of 20 keV 11-Feb-20 12:49 PM but it should be doable, if you don't care about power 11-Feb-20 12:49 PM if the whole system's under vacuum, ... do you even need a window? 11-Feb-20 12:49 PM it'd be inconvenient to put the specimens under vacuum 11-Feb-20 12:49 PM but in that case no, you don't 11-Feb-20 12:50 PM yep, water containing samples are difficult 11-Feb-20 12:50 PM ah tricky 11-Feb-20 12:50 PM if you want a continuously pumped 20kv tube and you don't care about power consumption, I could design something for sterilization 11-Feb-20 12:50 PM it'll need to be water cooled 11-Feb-20 12:50 PM and you'll need a fun power supply 11-Feb-20 12:50 PM but dumping an electron beam into a target isn't particularly complicated, just needs some simulation and ballpark math 11-Feb-20 12:52 PM I mean, you've got enough cryopumps @george 11-Feb-20 12:52 PM unrectified 20kV 500mA transformer 11-Feb-20 12:52 PM I don't see the issue with water samples in your system 11-Feb-20 12:52 PM hehe 11-Feb-20 12:52 PM nice idea 11-Feb-20 12:52 PM it'll need to be DC 11-Feb-20 12:52 PM why? 11-Feb-20 12:52 PM waves hands physics 11-Feb-20 12:52 PM but rectifying 20kv is pretty easy 11-Feb-20 12:52 PM 10 bucks worth of chinese diodes in series/parallel 11-Feb-20 12:53 PM sure, because all x-ray tubes work with purely DC... 11-Feb-20 12:53 PM why though? 11-Feb-20 12:53 PM funny fields and you don't want your entire chamber going to +20 11-Feb-20 12:53 PM the camber is still grounded 11-Feb-20 12:53 PM just the cathode will jump up and down 11-Feb-20 12:54 PM either way, rectifying makes things easier and it's cheap compared to the rest 11-Feb-20 12:54 PM thefields in a stainless steel chamber should be faaaaar faster than 50Hz 11-Feb-20 12:54 PM https://www.ebay.com/itm/High-Voltage-Diodes-30kV-100mA-HV-Tesla-30000V-0-1A-Fast-High-Voltage-Diodes/153139045123? 11-Feb-20 12:54 PM no it wont really because it will mean a big housing around the power supply 11-Feb-20 12:54 PM otherwise i can just have a cable 11-Feb-20 12:54 PM i know rectifying is easy 11-Feb-20 12:54 PM its not my first high voltage project 11-Feb-20 12:55 PM far easier to just stick a rectifier in series with the cable 11-Feb-20 12:55 PM i just dont see the reason why it should be nessecary 11-Feb-20 12:55 PM well, you can try without it 11-Feb-20 12:55 PM but I wouldn't 11-Feb-20 12:55 PM your current cycling to zero is going to eat a ton of power 11-Feb-20 12:56 PM full bridge then 11-Feb-20 12:56 PM unsmoothed 11-Feb-20 12:56 PM you're only going to get little pips above 20keV as a function of your line frequency 11-Feb-20 12:56 PM oh yeah there's that too 11-Feb-20 12:56 PM no 11-Feb-20 12:56 PM you're describing a system that is not worth cutting corners on 11-Feb-20 12:56 PM its 20kV mean 11-Feb-20 12:56 PM not 20kVp 11-Feb-20 12:56 PM still doesn't matter 11-Feb-20 12:56 PM you're spending a huge amount of time below 20 11-Feb-20 12:57 PM still gives me 25% duty 11-Feb-20 12:57 PM 25% of 2kW is not 2kW 11-Feb-20 12:57 PM your anode and cathode are going to be reversing polarity every AC cycle 11-Feb-20 12:57 PM but 25% of 8 is... 11-Feb-20 12:57 PM your anode and cathode are going to be reversing polarity every AC cycle @qualia of cause, bu so what? 11-Feb-20 12:57 PM you still need to dissipate the 8 11-Feb-20 12:57 PM no why? 11-Feb-20 12:57 PM at most 4 11-Feb-20 12:57 PM how are you going to dissipate 8kw spikes on a 5mm target 11-Feb-20 12:57 PM even water can't do it 11-Feb-20 12:58 PM in one direction there will be no current 11-Feb-20 12:58 PM x-ray tubes are by definition rectifiers 11-Feb-20 12:58 PM yes, but this one is short 11-Feb-20 12:58 PM i will loose whatever i spend below 20kV but not the reverse halfwave 11-Feb-20 12:59 PM I'm sorry, I can't watch this anymore... I can vow for @george , he really knows what he's doing and you don't need to treat him like any kid from the fusor forum. We've been through the calculations and he's not going to kill himself, nor the tube, transformer or whatnot. 11-Feb-20 12:59 PM Well, I'm just talking from the physics standpoint 11-Feb-20 12:59 PM <__ice9#6039> >>your anode and cathode are going to be reversing polarity every AC cycle >@qualia of cause, bu so what? Excuse me what? 11-Feb-20 12:59 PM @__ice9 I allways thought otating anode ones are just heat storage devices for getting high current density in the spot while not burning the material? 11-Feb-20 12:59 PM you'd be a) burning a lot of power b) melting your anode when it peaks 11-Feb-20 01:00 PM <__ice9#6039> If you don't understand why that matters then don't try to do this, please. 11-Feb-20 01:00 PM <__ice9#6039> Read. A lot. 11-Feb-20 01:00 PM i'm legitimately confused and would kinda just like to be on the same page here, like perhaps there's a language barrier or something but i'm at a loss and have some concerns 11-Feb-20 01:00 PM please guys, slow down for a moment 11-Feb-20 01:00 PM @__ice9 i kno what i WOULD get myself into, this is more of a theroretical project to see what i could do, not something i would actually build 11-Feb-20 01:01 PM @george yes i do have a pinout for the PXS5, for the analog ones. also for the digital but i did not map all the pins, only for supply and interlock 11-Feb-20 01:01 PM the pinout guru strikes again 11-Feb-20 01:01 PM if i want kW x-ray i have two crystallography tubes with Be windows laying besides me doing 1.5kW each if i want them to 11-Feb-20 01:01 PM Im very interested! 11-Feb-20 01:01 PM i already removed the connector but i think i will find the notes again describing the wiring 11-Feb-20 01:01 PM allright 11-Feb-20 01:01 PM so 11-Feb-20 01:01 PM calmly without treating me like a retard 11-Feb-20 01:01 PM why eexactly is a reversed voltage on an x-ray tube a problem? 11-Feb-20 01:01 PM i still dont understand why i would loose so much power 11-Feb-20 01:03 PM losing half the cycle, so half power 11-Feb-20 01:03 PM allright, more specific 11-Feb-20 01:03 PM x-ray tubes are optimized so that electrons are boiled off of the hot filament and then accelerated toward the target anode, which is often at an angle so as to 'aim' the x-rays through an exit window 11-Feb-20 01:03 PM why is dissipation a problem? 11-Feb-20 01:03 PM x-ray tubes are optimized so that electrons are boiled off of the hot filament and then accelerated toward the target anode, which is often at an angle so as to 'aim' the x-rays through an exit window @qualia i know how the ubes work 11-Feb-20 01:04 PM because you're going to need double the power, and there's only so much a piece of copper can take before melting 11-Feb-20 01:04 PM simply physical constraints, nothing else here 11-Feb-20 01:04 PM allright 11-Feb-20 01:04 PM if you flip that voltage around, you are now accelerating -- or attempting to accelerate -- electrons via cold-cathode or hot-work-function emission back towards the filament. right? i am pretty sure this is how electrons flow there 11-Feb-20 01:04 PM and what will a rectifier change about this situation? 11-Feb-20 01:04 PM I don't see why it would use twice the power, as it won't have much current in reverse polarity 11-Feb-20 01:04 PM it would not use twice the power 11-Feb-20 01:05 PM exactly 11-Feb-20 01:05 PM dude 11-Feb-20 01:05 PM you'd need to use twice the power to get the same average 11-Feb-20 01:05 PM im sorry 11-Feb-20 01:05 PM but im not the one not understading the issue here 11-Feb-20 01:05 PM also the tubes are some what non linear so with the sinusoidal voltage you get a lot of variation in focus and other parameters, for medical it is not so critical but also because of SMPS you see more and more DC 11-Feb-20 01:05 PM yes 11-Feb-20 01:05 PM hisrecommendaion was rectifying, not smoothing 11-Feb-20 01:05 PM the power use is not a physical phenomenon, nothing like that 11-Feb-20 01:05 PM just math 11-Feb-20 01:06 PM rectifying will change absolutely nothing about the voltage to current relation, peak power and average power 11-Feb-20 01:06 PM if you lose half the cycle, you will need to double your current to get the same average output power 11-Feb-20 01:07 PM i will just increase the pulsefrequency from 50 to 100Hz 11-Feb-20 01:07 PM and at some point you will be putting more power into the anode than the anode can dissipate into the surrounding mass and water 11-Feb-20 01:07 PM that half of the unrectified waveform where your tube is driven with incorrect polarity will lose you a lot of effective power -- it will still be generating x-rays, but they'll be coming out of the wrong side of the tube 11-Feb-20 01:07 PM it's not going to generate x-rays on the negative halfwave 11-Feb-20 01:07 PM not at this voltage especially 11-Feb-20 01:07 PM that half of the unrectified waveform where your tube is driven with incorrect polarity will lose you a lot of effective power -- it will still be generating x-rays, but they'll be coming out of the wrong side of the tube @qualia NO 11-Feb-20 01:08 PM hot anode/cold cathode would simply not do anything 11-Feb-20 01:08 PM look up how a vacuum tube diode works 11-Feb-20 01:08 PM 0 x-rays 11-Feb-20 01:08 PM just look it up 11-Feb-20 01:08 PM you can get cold cathode emission at 10kV+ 11-Feb-20 01:08 PM in the nanoamps maybe 11-Feb-20 01:08 PM yes 11-Feb-20 01:08 PM femtosievert per day 11-Feb-20 01:08 PM not 500mA+ 11-Feb-20 01:08 PM hisrecommendaion was rectifying, not smoothing @george yup i would agree it is for more output power 11-Feb-20 01:09 PM for this application it can be said that reverse current is 0 11-Feb-20 01:09 PM it may be true that doubling the beam frequency to 100Hz will lower peak thermal loading 11-Feb-20 01:09 PM but watercooling is concerned with only the average 11-Feb-20 01:09 PM and material ablation is dependant on the anode area beeing hit 11-Feb-20 01:10 PM correct, your issue is peak thermal loading here 11-Feb-20 01:10 PM you won't see any ablation here 11-Feb-20 01:10 PM it either melts or doesn't 11-Feb-20 01:10 PM wich if im only after doserate is completely open to be choosen 11-Feb-20 01:10 PM well, melting then 11-Feb-20 01:10 PM the only criterion is "keep it from melting" 11-Feb-20 01:10 PM but it wont melt in 10ms 11-Feb-20 01:11 PM in one pulse, unlikely yes 11-Feb-20 01:11 PM (though with enough power and if you believe, anything can melt) 11-Feb-20 01:11 PM power density 11-Feb-20 01:11 PM not power 11-Feb-20 01:11 PM it's an issue of how fast copper can transfer the heat within itself 11-Feb-20 01:12 PM if the average can be carried by the copper to water the ripple will not make a difference 11-Feb-20 01:12 PM it would mean that it would melt once per halfwave and then resolidify 11-Feb-20 01:12 PM wich is absolutely impossible if you ever seen a tig welder 11-Feb-20 01:12 PM there's an easy solution a solution 11-Feb-20 01:12 PM eitehr molten or solid, ms timescale doesnt make a difference in heating 11-Feb-20 01:12 PM metal jet anode 11-Feb-20 01:12 PM :P 11-Feb-20 01:13 PM there is no problem, so no solution required 11-Feb-20 01:13 PM making the anode would be fun 11-Feb-20 01:13 PM feeding the water just a few mm below the surface 11-Feb-20 01:13 PM but it's doable 11-Feb-20 01:14 PM no, its easy 11-Feb-20 01:14 PM really 11-Feb-20 01:14 PM you'd want a few fins in there 11-Feb-20 01:14 PM (oh, i was wrong about electron flow in vacuum tube diodes, my mistake. sorry for adding to the misunderstanding) 11-Feb-20 01:14 PM not just a pipe 11-Feb-20 01:14 PM i have a cruicible standing in front of me right now 11-Feb-20 01:14 PM made from copper 11-Feb-20 01:14 PM for melting tungsten 11-Feb-20 01:14 PM watercooled 11-Feb-20 01:14 PM multi kW vacuum electtronbeam system 11-Feb-20 01:14 PM its an empty copper pot with two water connections on the back and an empty space inside 11-Feb-20 01:14 PM this thing just flat instead and id have my anode 11-Feb-20 01:16 PM bit more complex than that 11-Feb-20 01:16 PM why? 11-Feb-20 01:16 PM vacuum feedthrough :P 11-Feb-20 01:16 PM sure, because the old ebeam use case was in open air... 11-Feb-20 01:16 PM well, the anode itself isn't a feedthrough 11-Feb-20 01:17 PM xD 11-Feb-20 01:17 PM no feedthrough 11-Feb-20 01:17 PM its easier to have a floating cathode 11-Feb-20 01:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/A0219-2-QF-B3AD3.png 11-Feb-20 01:17 PM at 20KV thats easy 11-Feb-20 01:17 PM think something like this 11-Feb-20 01:17 PM or 30 11-Feb-20 01:17 PM yeah you can float the cathode too 11-Feb-20 01:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/feed-50B9A.jpg 11-Feb-20 01:19 PM feedthrough low voltage high current, just a turned KF40 and a copper bar glued to the inside 11-Feb-20 01:19 PM goot to below 10-6mbar 11-Feb-20 01:21 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1-1-77E98.png 11-Feb-20 01:21 PM no problem doing the same with a piece of glass as insulator inbet ween the two 11-Feb-20 01:21 PM Could do something like this for the filament 11-Feb-20 01:21 PM yeah, but thats a bit overkill 11-Feb-20 01:21 PM just have two flanges 11-Feb-20 01:21 PM rated for 30kv apparently 11-Feb-20 01:22 PM Can we move general HV discussion to General please? :) 11-Feb-20 01:22 PM or even better a toroidal transformer integrated into the insulator 11-Feb-20 01:22 PM i think we are pretty much done 11-Feb-20 01:22 PM at least i have some aluminium foil to glue to some CF flanges 11-Feb-20 01:22 PM i have one 'o those, been thinkin' about tacking a filament onto it actually 11-Feb-20 01:22 PM Oh yeah that's a cool idea 11-Feb-20 01:22 PM no electrical connection to the filament, only magnetic 11-Feb-20 01:22 PM something something magnetic field messing up emission 11-Feb-20 01:46 PM <__ice9#6039> @Spirit cold cathode x-ray emission is definitely real-- it's just typically about 2-3 orders of magnitude weaker than those from hot thermionic etc. cathodes-- unless you are doing flash x-ray, when it just doesn't matter anymore because of explosive emission. 11-Feb-20 01:47 PM huh 11-Feb-20 01:47 PM interesting 11-Feb-20 01:50 PM <__ice9#6039> Here is a back of the envelope estimate for plausible continuous radiant power dissipation from a rotating-anode tube, but water cooling is likely to still be required because of heat being conducted from the anode to the rotational pass-through 11-Feb-20 01:50 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1581457219950-51F55.png 11-Feb-20 01:50 PM <__ice9#6039> Check the datasheet for your actual tube though. This is just to explain why they can handle more power. The beam targeted area is effectively far larger and offers some time for heat diffusion to a wider stripe instead of always focusing on the same few square mm. 11-Feb-20 01:53 PM Well, I think carbon nanotube field emission cathodes are pretty much the future for x-ray tubes 11-Feb-20 01:53 PM At least smaller ones 11-Feb-20 01:53 PM <__ice9#6039> By extension: yes an x-ray tube is a diode, but the leakage current is still enough to likely reduce filament life expectancy to some degree and in any event create x-ray emission from an undesired location. You can rectify 100kV easily by just stacking 4x 30kV diodes. It isn't hard and there is no reason to avoid doing it. 11-Feb-20 01:53 PM Easy to manufacture, high current, cheap, and incredibly robust 11-Feb-20 01:54 PM <__ice9#6039> Square waves are better for uniformity and allow using a smaller 100kV smoothing capacitor also, if that matters in the application at hand 11-Feb-20 01:54 PM <__ice9#6039> 100% agree, looks amazing 11-Feb-20 01:54 PM I wonder if bismuth sintering is required for my tube 11-Feb-20 01:54 PM Or if I can just get away with screen printing MWCNT pate 11-Feb-20 01:54 PM <__ice9#6039> I saw a paper doing this for flash x-ray and it performed great there as well 11-Feb-20 01:54 PM <__ice9#6039> I think they chose that method mostly for convenience 11-Feb-20 01:54 PM <__ice9#6039> If you just grew them straight onto aluminum with that MIT paper it would probably work fine 11-Feb-20 01:55 PM I have a chunk of bismuth, but I don't know how to easily turn it into nanoscale powder and keep it from turning into BiOx 11-Feb-20 01:55 PM <__ice9#6039> Might be more durable too 11-Feb-20 01:56 PM Growing CNTs is harder than just putting a paste blob on a rough piece of copper 11-Feb-20 01:56 PM <__ice9#6039> Yeah that's annoying. Personally I would just grow them on aluminum and be done with it. Totally air stable 11-Feb-20 01:56 PM <__ice9#6039> Let me find you the paper. It is truly not hard anymore. 11-Feb-20 01:56 PM I think a CNT forest would be the best cathode 11-Feb-20 01:56 PM <__ice9#6039> Someone found a better protocol 11-Feb-20 01:56 PM Has anyone tried CNT forests? 11-Feb-20 01:56 PM I've only seen non-homogenous SWCNTs and MWCNTs 11-Feb-20 01:56 PM Just a mush 11-Feb-20 01:56 PM <__ice9#6039> https://twitter.com/__ice9/status/1177790658590990336?s=19 11-Feb-20 01:56 PM <__ice9#6039> Sure these are mush, but they're pretty useful mush and I suspect they should work here too 11-Feb-20 01:57 PM Oh yeah they do 11-Feb-20 01:57 PM That paper described them mixing mush into organic solvent with bismuth, and screen printing it through 11-Feb-20 01:57 PM Mush is surprisingly robust for something nanoscale, and you can just buy it in a vial 11-Feb-20 01:58 PM <__ice9#6039> Yep I have some 11-Feb-20 01:58 PM I wonder how it survived screen printing 11-Feb-20 01:58 PM <__ice9#6039> https://twitter.com/__ice9/status/1054662563420610560?s=19 11-Feb-20 01:58 PM Surely if it did, I can just paint a bit on using a mask 11-Feb-20 01:58 PM would it survive ethanol? 11-Feb-20 01:58 PM should probably go to #general 11-Feb-20 01:58 PM <__ice9#6039> Yes. 11-Feb-20 01:58 PM <__ice9#6039> Ethanol is fine 11-Feb-20 01:58 PM <__ice9#6039> In fact you can just ultrasonically disperse them in toluene and spray it onto wet paint (or graphite paint) and they will stick 11-Feb-20 03:28 PM If anyone knows how to grow vertically grown carbon nanotubes I'm all ears lol. That's a big key to FEEP, for the cold field emission electron neutralizer 11-Feb-20 03:28 PM If you are doing flash x-ray stuff yourself, just go with velvet lol. It's the default choice for the superpower machines, and can be scales to any power level. Very high current density. Super low turn on voltage gradients of 25kv/m instead of over 100kv/m for bare metal. Much slower plasma expansion velocity than metal (hence slows impedance collapse), and has very good beam uniformity. Literally just spray glued to the cathode surface. Dirt cheap and simple. I've already designed EXEDA with it to support upwards of several kA beams 11-Feb-20 04:46 PM <__ice9#6039> @Applied_Ion Growing VANTAs is harder than that aluminum-MWCNT new record ultra-black coating paper I linked above, but there are still plenty of papers on viable protocols. Just search e.g. VANTA CVD. 11-Feb-20 04:46 PM this is #radiation 11-Feb-20 04:46 PM <__ice9#6039> It was a question about field emission 11-Feb-20 04:46 PM fair enough 11-Feb-20 04:50 PM I don't necessarily need VANTA, that is just what everyone does for FEEP neutralizers, but if paint on MWCNT works I'll take that any day lol 12-Feb-20 09:16 AM Allright, i have now fought for a day with several paths of software trying to get the RVG6100 Sensor to work 12-Feb-20 09:16 AM to no success 12-Feb-20 09:16 AM Is there anyone around here with experience in this regard? 12-Feb-20 09:16 AM I installed the carestream driver/utilities, the sensor is recognized by win7 properly, but neither by dexis nor the service tool provided by carestream 12-Feb-20 09:16 AM since the usb connection is working with no problem and i dont get bad images instead of no images at all im pretty certain its still a software problem 12-Feb-20 10:37 AM is it usb-serial ? 12-Feb-20 10:37 AM oh nevermind, it's an image sensor 12-Feb-20 10:37 AM if nobody else has any experience, https://twitter.com/johndmcmaster may have worked with those sensors before. could be worth reaching out 12-Feb-20 11:41 AM Thanks! Who knows, maybe he can help me ^^ 12-Feb-20 11:41 AM having hardware that is 100% useless without proprietary software is really really frustrating... 12-Feb-20 11:53 AM yeaah x.x 12-Feb-20 11:53 AM seems ripe for reverse engineering, but there's just a shortage of people with the skillset + resources needed to really tear one open 12-Feb-20 11:55 AM @george have you installed the dental imaging software? 12-Feb-20 11:55 AM try doing the full dentist path 12-Feb-20 11:56 AM i did 12-Feb-20 11:56 AM all day long 12-Feb-20 11:56 AM no imagin software can see the sensor, only the driver lists it perfectly right in the system 12-Feb-20 11:57 AM huh, weird 12-Feb-20 11:57 AM so some interface between driver and imaging software doesnt expect this sensor type/number whatever 12-Feb-20 11:57 AM talk to John, he goes by digshadow on freenode 12-Feb-20 12:02 PM any other way t contact without another registration? 12-Feb-20 12:03 PM registering for a handle on freenode isn't strictly necessary, only if you choose a handle that someone else has already registered or if you're trying to join a registration-required channel 12-Feb-20 12:03 PM (correct me if i'm wrong) 12-Feb-20 12:04 PM ah ok 12-Feb-20 12:04 PM and ow to find him then? 12-Feb-20 12:04 PM last tme i was in contact with irc is a looong time ago 12-Feb-20 12:05 PM perhaps just /msg digshadow Hello! 12-Feb-20 12:05 PM may start a dialog straight away 12-Feb-20 12:05 PM assuming he's online.. he seems like the sort to use a bouncer/always be online 12-Feb-20 12:06 PM eh 12-Feb-20 12:06 PM he's online but hasn't talked in 159 hours 12-Feb-20 12:07 PM its not organized in chatrooms? 12-Feb-20 12:07 PM it is 12-Feb-20 12:07 PM sry, i have no idea how freenode works 12-Feb-20 12:07 PM freenode is just an IRC server, with regular IRC channels 12-Feb-20 12:07 PM aaaahh ok 12-Feb-20 12:07 PM eh 12-Feb-20 12:07 PM autoaway 12-Feb-20 12:10 PM i'll poke him on twitter, see if he even knows anything about it 12-Feb-20 12:12 PM that would be nice! 12-Feb-20 12:12 PM Oh crap today's MTVRE 12-Feb-20 12:12 PM I'll just, like, see him today 12-Feb-20 12:12 PM but, messaged anyways 12-Feb-20 12:14 PM see him? 12-Feb-20 12:14 PM in person? 12-Feb-20 12:14 PM lol 12-Feb-20 12:14 PM yeah 12-Feb-20 12:14 PM neat 12-Feb-20 12:14 PM he throws a monthly reverse engineering meetup 12-Feb-20 12:14 PM shenanigans ensue 12-Feb-20 12:16 PM xD 12-Feb-20 12:16 PM cool 12-Feb-20 01:13 PM bah, i got a pair of low-background lead counting chambers yesterday... asked the seller to weigh them, if she could, to see if i'm going to need a ridiculous load-gate-equipped truck to move them, or if i can get away with a miserable little uhaul 12-Feb-20 01:13 PM hope she responds soon.. vibrates 12-Feb-20 01:13 PM they have weird pickup times (wed-fri 8am-3pm) and i'd love to play with them over the weekend 12-Feb-20 01:13 PM i want my birthday lead 12-Feb-20 01:14 PM don't hurt yourself 12-Feb-20 01:15 PM i will enlist some Muscular Housemates(tm) to assist :D 12-Feb-20 01:15 PM but, they're on wheels, thankfully 12-Feb-20 01:15 PM so i can just scooch em up a ramp if they're less than a thousand pounds each 12-Feb-20 01:15 PM well yes, but think about the energy you have to use to get them up eg. a 1 cm ramp 12-Feb-20 01:15 PM oh, well, true 12-Feb-20 01:15 PM the trick is to get a running start, and to really put your back into it :D 12-Feb-20 01:15 PM ducks 12-Feb-20 01:22 PM Remember to lift with a jerking twisting motion! 12-Feb-20 01:22 PM Thrash violently to assert dominance 12-Feb-20 01:40 PM You definitely won't pinch the nerves on your spinal column in a horrendously painful manner, not at all! 12-Feb-20 01:41 PM Lead is a soft metal. Therefore it's harmless 12-Feb-20 01:47 PM Not to mention the sweet taste, if it tastes good it must be good for you 12-Feb-20 01:48 PM Slice it up like cake! 12-Feb-20 01:55 PM oh yay they're only 175lbs each 12-Feb-20 01:55 PM that's extremely reasonable 12-Feb-20 01:55 PM might as well just carry 'em on public transit 12-Feb-20 01:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/membrane-6A0CF.jpg 12-Feb-20 01:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/KF-E4462.jpg 12-Feb-20 01:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/succ-FAC1D.jpg 12-Feb-20 01:56 PM Oh. Oh no. 12-Feb-20 01:56 PM You're doing what I think you're doing 12-Feb-20 01:57 PM regarding yesterdays disgussion about vacuuming and pressure relieff 12-Feb-20 01:57 PM yeah that's the bellows 12-Feb-20 01:57 PM i just allways assumed there was a seperate channel with the power supply under it 12-Feb-20 01:57 PM because tehre never was any oil leaking to the tube chamber from there 12-Feb-20 01:57 PM but turns out the PS is potted in epoxy 12-Feb-20 01:57 PM and there is only a very small pot connected via oil channels 13-Feb-20 01:23 AM Ok, stupid question 13-Feb-20 01:23 AM easy way to identify borated paraffine? 13-Feb-20 01:23 AM we got some unknown stuff that breaks with a really sparkly edge 13-Feb-20 01:23 AM it's clear-ish when molten, at least no visible particulate 13-Feb-20 01:28 AM ... XRF? :P 13-Feb-20 01:28 AM it definitely looks heavily doped with something 13-Feb-20 01:28 AM but I've also seen paraffin crystallize similarly 13-Feb-20 03:16 AM What the hell, united nuclear 13-Feb-20 03:16 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6AEE4.png 13-Feb-20 04:43 AM hehe 13-Feb-20 04:48 AM <__ice9#6039> That sounds pretty costly. Just melt boric acid into paraffin and cast it into whatever shape. 13-Feb-20 06:42 AM that doesn't really work, as they don't mix well and have different densities 13-Feb-20 06:42 AM but there's another issue 13-Feb-20 06:42 AM with borated moderators 13-Feb-20 06:42 AM for moderating 13-Feb-20 07:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200213_102944-7AC89.jpg 13-Feb-20 07:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200213_103416-7E721.jpg 13-Feb-20 07:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200213_162023-14B67.jpg 14-Feb-20 12:52 AM <__ice9#6039> Here you go. https://patents.google.com/patent/CN1094498C/en Granted, powder instead of melting. 14-Feb-20 12:54 AM Apparently the best material you can get is borated polyethylene, followed by borated paraffin 14-Feb-20 12:54 AM Makes sense, H releases 2.225MeV gammas upon capture, boron 478keV 14-Feb-20 01:09 AM @__ice9 there I go what? 14-Feb-20 01:09 AM that patent doesn't answer my question at al 14-Feb-20 01:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200214_095738-3019C.jpg 14-Feb-20 01:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200214_100322-22888.jpg 14-Feb-20 02:30 AM <__ice9#6039> >that doesn't really work, as they don't mix well and have different densities 14-Feb-20 02:30 AM <__ice9#6039> I provided a method to easily overcome the problem that you stated. 14-Feb-20 02:30 AM <__ice9#6039> I didn't say anything about your earlier question of identification, but to me the most obvious answer would be a flame test 14-Feb-20 02:30 AM <__ice9#6039> @GigaSquirrel if it burns green, it is borated, else likely not 14-Feb-20 08:37 AM Going to drop a reminder here that the paraffin technique for neutron shielding was abandoned by DOE, and most everyone else, for the very good reason that you have just added a whole lot of flammable load to your workspace. Keep a large fire extinguisher handy just in case. 14-Feb-20 08:37 AM Also, it is super gross cleaning up your shielding after it melts on a hot day when the AC fails. 14-Feb-20 08:44 AM I don't think we've ever had a day hot enough to melt it 14-Feb-20 08:44 AM but I'll keep it in mind, thanks ^^ 14-Feb-20 08:44 AM and I'm not using it as a shield, but to moderate and (when borated) calculate neutron flux 14-Feb-20 08:44 AM well, I suppose I will end up using it mostly as shielding and use boric acid solution for flux measurements 14-Feb-20 08:53 AM It was fun when we’d get young interns who’d say “We can just pour our own paraffin shielding. Cheap and get any shape we want, boss!” And then the old timers, some who worked with Teller, let’s see if I can remember this right, “Never again. You’ve got a PhD . That means you are capable of learning by listening and learning rather than trial and error. Learn from my errors. Boreated HDPE is a lot cheaper in the long run than paraffin. Requires machining rather than casting, but it won’t let go on you when all the equipment heats the room up.” 14-Feb-20 08:53 AM hehe 14-Feb-20 08:54 AM I miss the 70 & 80yo weaponeers and their “Listen to me you little twerp” discussions. Was the recipient of more than a few of those myself. 14-Feb-20 08:54 AM oh I'd love to talk to someone like that 14-Feb-20 08:54 AM lots of experimental experience 14-Feb-20 08:54 AM also I'm not sure you can get borated PE here as an individual 14-Feb-20 09:00 AM They were extremely fun people. Crotchety, but well earned. B-HDPE and borated glass, are relatively available, just not super cheap. Never hurts to ask a place like TAP Plastics. They are the fantastic plastic place, just like their ad jingle says. 14-Feb-20 09:02 AM I'm here in germany, since our tax system is a bit messed up many companies don't sell to individuals 14-Feb-20 09:04 AM Schott won't? 14-Feb-20 09:04 AM the only old person I talked to in that regard was someone everyone called the "Detector Magician" who was responsible for repairing like 90% of the detectors at GSI, including Euroball etc 14-Feb-20 09:04 AM never tried, but thanks for the hint! 14-Feb-20 09:05 AM Their borated and leaded glass, all of their many different grades of it, is [fingerkisses] magnificent. 14-Feb-20 09:05 AM oh, nice 14-Feb-20 09:05 AM 'tho I don't really have a need for special glass 14-Feb-20 09:05 AM plus a huge piece of leaded glass is on its way to me 14-Feb-20 09:05 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2020-02-14_13-44-31-09B22.jpg 14-Feb-20 09:05 AM but by the looks of it the lead content isn't too high 14-Feb-20 09:06 AM Their only real competitor in this space is Corning and Schott is generally higher quality with a larger variety. 14-Feb-20 09:07 AM good to know, thanks ^^ 14-Feb-20 09:07 AM do they also do stuff like Li doped? 14-Feb-20 09:07 AM also their site doesn't respond to any of my inputs... 14-Feb-20 09:08 AM Schott quite literally makes everything. 14-Feb-20 09:08 AM I suppose I should have started by saying Schott is the glassmaking part of Zeiss. 14-Feb-20 09:10 AM ohh, til 14-Feb-20 09:10 AM oh and also TIL: I always thought schott duran was a name for glass from schott, but apparently that's a glass made by duran 14-Feb-20 09:10 AM this is not confusing at all 14-Feb-20 09:11 AM This is now turning into more of a #resources discussion so I'll stop myself now and consider this my good deed for Germany today. 14-Feb-20 09:12 AM oi, I'm the admin here to tell people when this is getting too ot 14-Feb-20 09:12 AM ...dang it you're one as well 14-Feb-20 09:12 AM anyways, thanks for the info ^^ 14-Feb-20 09:13 AM Here to help! 14-Feb-20 10:30 AM @GigaSquirrel is there a possible way around the no sales to individuals thing with the german equivalent of LLCs here in the USA? 14-Feb-20 10:30 AM yep 14-Feb-20 10:31 AM that is how a few people I know have gotten around those sorts of policies 14-Feb-20 10:31 AM just a lot of paperwork 14-Feb-20 10:31 AM it's on my to do list for this year, but at the moment I'm still working a student job and that will just cause waaaay more paper work when I do it now 14-Feb-20 10:32 AM makes sense, just was curious if that is how it works in your part of the world too 14-Feb-20 11:47 AM re: the delights of paraffin 14-Feb-20 11:47 AM https://twitter.com/profanegeometry/status/1137980372275290112 14-Feb-20 11:47 AM extracting my tube from that was fun :D 14-Feb-20 11:47 AM never did get around to 3D printing forms for the stuff, honestly wish i had the fundollars to throw at some HDPE and be done with it 14-Feb-20 11:54 AM i still need NIM or homebrew stuff to drive my tubes before i worry about moderators 14-Feb-20 11:54 AM need to find a way to ID some plastic i was given to see if it might work, doubtful as it is recycled material (counter tops)...but the person who gave it to me said it was HDPE 14-Feb-20 11:59 AM i've successfully driven my B10 tube with a $4 amazon HVDC module, a fistful of 10-meg resistors, and a couple of hv ceramic capacitors, before. you can get away with very little sometimes, though it's not liable to be pretty or low-noise 14-Feb-20 11:59 AM He3 needs a little more care than that tho 14-Feb-20 11:59 AM also, it definitely could be -- a lot of, like, cutting boards are just plain old HDPE. best if its not got any dyes or coatings on it 14-Feb-20 11:59 AM there may be some stone-age way of identifying it as HDPE by cutting off a sliver and burning it or something, in lieu of a recycling identification stamp or somesuch 14-Feb-20 12:03 PM So what kind of neutron sources are you looking to measure? 14-Feb-20 12:04 PM fusors! 14-Feb-20 12:05 PM Ah, of course. Well it's simple then, try out your current slabs to see if you get more counts than without the slabs 14-Feb-20 12:05 PM oh that's boring 14-Feb-20 12:05 PM I want to do proper flux measurements 14-Feb-20 12:06 PM phones up RSICC, 'Hello I was just building a fusor and I was wondering if I could get a copy of MCN*click*' 14-Feb-20 12:06 PM Hmm, calibrating detector efficiency would be tough, got a He3 tube? @GigaSquirrel 14-Feb-20 12:06 PM calibrate the efficiency of my hpge, get a boron solution of known concentration, arrange the whole stuff and go look for the 477 keV capture peak, determine reaction rate from that and calculate backwards from there to neutron flux 14-Feb-20 12:06 PM lol not just one 14-Feb-20 12:06 PM I'm still waiting on RSICC to approve my second copy of MCNP... 14-Feb-20 12:06 PM You can't use your existing copy for anything other than the approved purpose 14-Feb-20 12:07 PM that's no fun at all 14-Feb-20 12:08 PM You're supposed to destroy the disk after you're done with it. I've also got SCALE on the way as well 14-Feb-20 12:08 PM Super excited about that 14-Feb-20 12:10 PM I wanna do real physics and not just get internet points in the fusor forum for doing the same stuff everyone else does 14-Feb-20 12:10 PM Thought about using activation counters to calibrate? 14-Feb-20 12:11 PM oh I've already got a calibrated geometry for three of my detectors 14-Feb-20 12:12 PM Indium or silver foil around a good detector with known efficiencies. Put it next to the fusor, turn it off and count. 14-Feb-20 12:12 PM I'll do all those tings 14-Feb-20 12:12 PM but mostly I'm after prompt gammas, not activation stuff 14-Feb-20 12:21 PM also, it definitely could be -- a lot of, like, cutting boards are just plain old HDPE. best if its not got any dyes or coatings on it @qualia thats the problem, as counter top material there are dyes and stuff in all of it. 14-Feb-20 12:21 PM i mostly use it just as scrap material for work holding at the moment but i have a decent stack of it 14-Feb-20 12:27 PM Best effect achieved if the dye is cobalt-based 14-Feb-20 12:36 PM realizing this server has a severe lack of snarky custom emojis 14-Feb-20 12:36 PM [beryllium] + [cheese grater] 14-Feb-20 12:47 PM How would you represent beryllium in this case? 14-Feb-20 12:47 PM To me it's just BeO which means RF goodies with that dirty white ceramic. 14-Feb-20 12:48 PM pink ceramic is beo too 14-Feb-20 12:48 PM though it could also be erbium oxide 14-Feb-20 12:50 PM i was thinking just a dark gray square/cylinder/lump with 'Be' on it 14-Feb-20 12:50 PM uncreative 14-Feb-20 12:50 PM that works too 14-Feb-20 12:50 PM to be honest I'm still tempted to work with beryllium for my x-ray tube design 14-Feb-20 12:50 PM just... in a tub of alcohol, with all the tools submerged 14-Feb-20 12:50 PM I can buy polished beryllium rods really cheap 14-Feb-20 12:50 PM I can also buy a water-soluble beryllium salt D: 14-Feb-20 12:51 PM oh no 14-Feb-20 12:52 PM is there such a thing as light metal poisoning? 14-Feb-20 12:52 PM hmmm 14-Feb-20 12:52 PM beryllium salts shouldn't cause berylliosis at all 14-Feb-20 12:52 PM (but they're useless for me) 14-Feb-20 12:56 PM You'd think that, but you'd be very, very wrong. 14-Feb-20 12:56 PM The damage mechanism of CBD (Chronic Beryllium Disease) is a dramatic overreaction by your immune system, kinda like lupus, as it goes haywire and starts attacking everything. Something like nickel allergy, but much worse. People normally get it by inhaling beryllium dust, so we're used to talking about lung effects. Beryllium sensitization such that your body then reacts in the haywire mode the next time can happen from pretty much any exposure, anywhere on the body. 14-Feb-20 01:00 PM So it's less inhalation and more just having beryllium and compounds in/on your body 14-Feb-20 01:00 PM Keep your beryllium safely bound up as emeralds, refrain from crushing them and snorting them, and you should be fine. 14-Feb-20 01:01 PM beryllium is the perfect material for x-ray tube windows, aside from the fact that it sucks even in pure metal form 14-Feb-20 01:01 PM Inhalation is the most common mode of exposure, but you can hit sensitization by simple skin contact. All a question of how weak or strong a rat you are vs. exposure and you can't know that in advance. Beryllium is a wonder material, just like asbestos. They just have some annoying toxicity issues. 14-Feb-20 01:02 PM I really want to replace it with lithium 14-Feb-20 01:02 PM it's pretty much inert compared to beryllium, body-wise, unless you seriously get it in you 14-Feb-20 01:02 PM but it's very very not inert in regards to everything else 14-Feb-20 01:03 PM Alas. We tend not to operate x-rays under argon atmosphere. 14-Feb-20 01:04 PM the output window can easily be covered with polyimide film or something equally transparent to x-rays 14-Feb-20 01:04 PM but the actual manufacture process, the inside of the tube would still have to be exposed 14-Feb-20 01:04 PM oh and it melts at 180C, which is fun. 14-Feb-20 01:04 PM sputtering anything onto it would be a challenge and a half 14-Feb-20 01:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200214_224055-C66E4.jpg 14-Feb-20 01:43 PM testing the snmo5 BF3 prop detector 14-Feb-20 01:43 PM no adaptershaming plz 14-Feb-20 01:48 PM so many connector condoms 14-Feb-20 01:48 PM yeah he's really into that 14-Feb-20 01:50 PM now feels slightly better about sometimes storing random stuff in their bin 14-Feb-20 01:53 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200214_225331-5C41D.jpg 14-Feb-20 01:53 PM dn40 pvc sewar pipe and end plug, plus a lot of copper / al foil 14-Feb-20 01:53 PM aint stupid if it works 14-Feb-20 02:01 PM oh so that's what's going on there 14-Feb-20 02:01 PM i just thought the tube had a huge diameter 14-Feb-20 02:02 PM it also kinda is 14-Feb-20 02:02 PM 35mm od 14-Feb-20 02:02 PM thinking about getting a few of those myself 14-Feb-20 02:02 PM seem decently sensitive 14-Feb-20 02:02 PM 96 counts over 30 mins 14-Feb-20 02:02 PM and now without the moderator 14-Feb-20 02:09 PM just ambient, or with a check source/fusor? 14-Feb-20 02:11 PM ambient 14-Feb-20 02:11 PM have no check source here 14-Feb-20 02:11 PM oh gawd speaking of check sources 14-Feb-20 02:11 PM we recently came across one labeled "Radium-D-Beryllium" 14-Feb-20 02:11 PM 30 mCi 14-Feb-20 02:11 PM uh oh 14-Feb-20 02:11 PM RaBe you'd think, right? 14-Feb-20 02:11 PM but the dose rate wasn't anywhere near what you'd expect for what's about 1 GBq of Ra226 14-Feb-20 02:12 PM <__ice9#6039> @Spirit yes the salts are also toxic and actually even more prone to causing acute beryllium disease 14-Feb-20 02:12 PM took me all day of being in a bad mood because I don't understand something 14-Feb-20 02:12 PM until it dawned upon me 14-Feb-20 02:12 PM Radium-D makes me think it was some isotope of something we hadn't named yet in the olden days 14-Feb-20 02:12 PM like how we had eka-thorium and other stuff for a minute 14-Feb-20 02:13 PM yeah they labeled it A- B- C -D etc 14-Feb-20 02:13 PM Ra-D is Pb210! 14-Feb-20 02:13 PM wat 14-Feb-20 02:13 PM that decays to Po210 which has a lot of alpha activity and actually produces the neutrons, but they used the Pb because it has some years half life instead of the days of Po 14-Feb-20 02:13 PM oh but it gets worse 14-Feb-20 02:15 PM oh huh. polonium cow 14-Feb-20 02:15 PM sorta 14-Feb-20 02:15 PM Po218 is Ra-A Pb-214 is Ra-B Bi214 is Ra-C Po214 is Ra-C' Tl210 is Ra-C'' Pb210 is Ra-D Bi210 is Ra-E Po210 is Ra-F Pb206 is Ra-D 14-Feb-20 02:15 PM like 14-Feb-20 02:15 PM ??? 14-Feb-20 02:15 PM I hate it 14-Feb-20 02:15 PM also yes, Po cow, I really like the Idea 14-Feb-20 02:16 PM order of discovery, i guess? :D 14-Feb-20 02:16 PM fair enough 14-Feb-20 02:16 PM But why did they still use that system in '67 14-Feb-20 02:16 PM the source itself is quite cute, about pencil-sized and does like 14k n/s 14-Feb-20 02:25 PM where'd you find it? >.> 14-Feb-20 02:25 PM just rattling around in a junk drawer someplace? 14-Feb-20 02:26 PM heh, I wish 14-Feb-20 02:26 PM "find" 14-Feb-20 02:26 PM a radiation safety company here owns it and a friend got to work with it to test his detector 14-Feb-20 02:27 PM ahhh 14-Feb-20 02:29 PM and now we're wondering how possible it is to extract the Ra-D from ore... 14-Feb-20 02:29 PM oh btw I found some very interesting papers on all kinds of spectroscopy incl stuff like chemical preparation for alpha spectroscopy etc 14-Feb-20 02:29 PM but they're all in german 14-Feb-20 02:29 PM upload it to #resources or not? 14-Feb-20 02:31 PM i'd say so, especially if they're OCR'd 14-Feb-20 02:31 PM some of them are 14-Feb-20 02:33 PM The extraction from ore is some column chemistry with non-trivial acids. Isotope geochemistry is a lot of fun and doing with radioisotopes lets you know you actually did it right, unlike stable isotope work. 14-Feb-20 02:33 PM Stable isotope work means crossing your fingers until you throw things on the mass spec to see if you did it right. 14-Feb-20 02:34 PM yeah it was more of a thought than a plan, I don't know too much about (radio)chemistry and am too scared to work with radioactive solutions 14-Feb-20 02:35 PM When you've developed the appropriate respect for 16M HF, you can start doing ore extractions. 14-Feb-20 02:36 PM I've got some friends who are chemists, maybe they can do something in their lab, but I sure as hell won't do anything at home 14-Feb-20 02:36 PM don't even have a fumehood 14-Feb-20 02:37 PM I used to run a hydrofluoric still, among other things, in my isotope geochem lab for three years. I remain twitchy around HF. 14-Feb-20 02:38 PM the chip decapping people and their affinity for HF shenanigans frightens and confuses me 14-Feb-20 02:40 PM yep... 14-Feb-20 02:40 PM always nice to walk through someone's lab/workspace and spot a little blue box of calgonate and immediately know what nonsense they're up to 14-Feb-20 02:41 PM :X 14-Feb-20 02:44 PM 26 counts without moderator 14-Feb-20 02:45 PM neat :D 14-Feb-20 02:45 PM sounds like your moderator moderates 14-Feb-20 02:45 PM Sounds like a moderately successful test. 14-Feb-20 02:46 PM any plans to remove the pvc pipe? 14-Feb-20 02:46 PM ya it's not borated XD 14-Feb-20 02:46 PM yeah at some point 14-Feb-20 02:46 PM but it's not my detector so I don't care duck 14-Feb-20 02:46 PM borate the pvc pipe 14-Feb-20 02:46 PM polyvinyl borate 14-Feb-20 02:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/17n7qf-A4956.png 14-Feb-20 11:59 PM friday night ebaying and came across these... any guesses as to what kind of detectors these are? https://www.ebay.com/itm/Eberline-Radiation-Survey-Probe/273928073935 14-Feb-20 11:59 PM cute little things 14-Feb-20 11:59 PM look like energy compensated geiger müller 14-Feb-20 11:59 PM or fission chambers 15-Feb-20 12:00 AM thats what i was leaning toward, the energy compensated GMs, but they are about half the size of the ones i have seen in similar form factors 15-Feb-20 12:19 AM oh and also we just calculated that those snmo5 have a gas gain of ~20, assuming they're BF3 mixed with argon 15-Feb-20 12:19 AM which is on the low side of things, but that seems to be common with russian detectors 15-Feb-20 01:01 AM Looks a bit like an old peanut probe, handy for a dose rate monitor inside an x-ray unit or radiography suite. So, yeah, energy compensated GM but not one I specifically recognize. 15-Feb-20 09:19 PM <__ice9#6039> HF is unfortunately consistently useful in ore extractions and reprocessing of oxide materials. 15-Feb-20 09:19 PM <__ice9#6039> Frankly the stuff is quite intimidating, and I would strongly recommend using shoulder length gloves over ordinary ones, a full face shield with HF-rated acid gas respirator, a functioning fume hood with external exhaust or outdoor bench setup, a lab coat, a neck shield, a blast shield in case of vessel failure, and having plenty of prepared rapid-absorbing calcium gluconate gel and powdered calcium gluconate on hand. Concentrated HF is easily as bad as cyanide solutions if not worse. 15-Feb-20 09:19 PM <__ice9#6039> Fluoride ion salts are also hazardous even when neutral, merely less so. 15-Feb-20 09:34 PM The bonus is that HF exposure is completely symptomless and you can't feel it 15-Feb-20 09:34 PM Whereas you can at least smell cyanide 15-Feb-20 09:34 PM But with HF you only realize when it's too late 16-Feb-20 06:25 AM oh geez 16-Feb-20 06:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4AE24.png 16-Feb-20 06:25 AM A small pallet of 400 kg lead 16-Feb-20 06:25 AM will take some time to get it to my place tho 16-Feb-20 07:12 AM niceeeee 16-Feb-20 07:12 AM want <3 16-Feb-20 07:32 AM you'll pay three times what I paid for shipping alone 16-Feb-20 07:33 AM I know :( 16-Feb-20 11:07 AM Look at you, with your fancy painted lead 16-Feb-20 11:25 AM getting jealous? :P 16-Feb-20 11:28 AM I can neither confirm nor deny 16-Feb-20 11:35 AM now I gotta spend... crunches numbers hits buttons on calculator... Lots on copper! 16-Feb-20 11:35 AM naw, only a tube or a bit of sheet of a few mm 16-Feb-20 11:36 AM nope 16-Feb-20 11:36 AM as far away as possible from the detector, not directly around it 16-Feb-20 11:36 AM so a bit of a lot of sheet 16-Feb-20 11:36 AM yep 16-Feb-20 11:37 AM but you only need a few mm to shield from pb 16-Feb-20 11:37 AM especially at longer distances 16-Feb-20 11:37 AM yep 16-Feb-20 11:37 AM I've seen 2-3mm slash the pb peak down into the compton 16-Feb-20 11:38 AM yeah, aiming for 5, will realistically end up with 2-3 16-Feb-20 11:38 AM don't want too much copper because beta + copper = improvised x-ray not-tube 16-Feb-20 11:39 AM yeah but with a peak at energies my detector doesn't see anymore 16-Feb-20 11:39 AM which is the whole point of the copper 16-Feb-20 11:39 AM not just ka/kb but non-characteristic 16-Feb-20 11:39 AM but that's minescule 16-Feb-20 11:39 AM grumble grumble hpge 16-Feb-20 11:39 AM just trust me, I know what I'm doing 16-Feb-20 11:40 AM I know you know 16-Feb-20 11:40 AM I've worked with enough of those systems to know how to calculate and build one myself... 16-Feb-20 11:40 AM with fancy house interior-adapted painted lead bricks 16-Feb-20 11:40 AM some conformally coated polished copper will complete the picture 16-Feb-20 11:40 AM and one of those pivoting swing out lead lids 16-Feb-20 11:42 AM well, the limit is what I can get and manufacture at home 16-Feb-20 11:42 AM couple bits of pipe and some bearings 16-Feb-20 11:42 AM you can do that 16-Feb-20 11:42 AM not in the space I have for the detector 16-Feb-20 11:42 AM too little floor area 16-Feb-20 11:43 AM some super-industrial hinges then? 16-Feb-20 11:43 AM or drawer rails 16-Feb-20 11:43 AM that still doesn't stop the whole thing from tipping over 16-Feb-20 11:44 AM something can be engineered 16-Feb-20 12:41 PM @GigaSquirrel ohh i would also love to get my hands on such a nice radiation shielding set, you are so lucky 16-Feb-20 12:46 PM Oh you wont believe how happy I am about it 17-Feb-20 05:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200217_142744_243-3E0A4.jpg 17-Feb-20 05:37 AM oh boi it's getting real 17-Feb-20 05:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/800px-Bleiburg_Heisslabor-EE2DD.jpg 17-Feb-20 05:37 AM looked like this once 17-Feb-20 05:58 AM oh man thats beautiful 17-Feb-20 08:16 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200217_165659-21A7B.jpg 17-Feb-20 08:16 AM ohhh! 17-Feb-20 08:16 AM 518 Bq and 0.82 Bq XD 17-Feb-20 08:46 AM neat 17-Feb-20 09:16 AM Pretty setup. 17-Feb-20 10:50 AM what was the original setup? 17-Feb-20 11:08 AM The original setup looks like a medical radioisotope dose measurement system 17-Feb-20 11:08 AM You milk the technetium cow, put that in a vial, stick that in, and it tells you how how your injection is, and then you dilute it to the doctor's dosage 17-Feb-20 11:08 AM https://strahlungstechnik.melit.ch/produkte-detail/isomed-2010-aktivimeter/ 17-Feb-20 11:08 AM Yep, it's exactly what it is. 17-Feb-20 11:08 AM Radioisotope dose/activity calculator/measurer 17-Feb-20 11:13 AM ahh interesting 17-Feb-20 11:13 AM for some reason when i opened the photo before it only got about half enlarged heh restarted my browser and now i can read the screen myself 17-Feb-20 11:19 AM https://www.flickr.com/photos/bionerd/5154865934 17-Feb-20 11:19 AM Said technetium cow 17-Feb-20 11:19 AM Huge Mo-99 source inside. As it decays, Tc-99m builds up. You put saline through it and wash the Tc-99mm into a vial. 17-Feb-20 11:21 AM medical isotopes are not really something i would want to deal with every day but i am glad there are people who do 17-Feb-20 11:21 AM It's pretty safe but yeah, you deal with really hot short-lived isotopes by hand 17-Feb-20 11:22 AM lot of the lost source incidents involve them too 17-Feb-20 11:22 AM which is better than something like a density gauge but still...how does something like that get lost in transport haha 17-Feb-20 11:23 AM Yeah, glass, syringes, people... 17-Feb-20 11:23 AM or they forget to put some beads in 17-Feb-20 11:23 AM There's plenty of incidents where soil-whatevermeters get damaged too 17-Feb-20 11:23 AM With huge Sr-90 sources 17-Feb-20 11:24 AM i have family who work at a hospital and they had some of the source beads go unaccounted for...whole hospital was drowning in paperwork 17-Feb-20 11:24 AM turned out the company never actually sent them the whole shipment 17-Feb-20 12:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200217_230017-7D77D.jpg 17-Feb-20 12:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200217_225958-26998.jpg 17-Feb-20 12:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200217_225939-0E64C.jpg 17-Feb-20 12:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200217_225921-B498F.jpg 17-Feb-20 12:01 PM Good news and bad news. 17-Feb-20 12:01 PM Or bad news and bad news. I don't know yet. 17-Feb-20 12:01 PM Made a nice imprint. Sheared two screws clean off. 17-Feb-20 12:01 PM How they managed this $f8&H&up through 16 layers of tightly packed bubble wrap is beyond me. 17-Feb-20 12:01 PM A faint hint of oil is all over the front part, but no obvious leaks or damage. I think. 17-Feb-20 12:01 PM @TecKonstantin for your viewing horror. 17-Feb-20 12:01 PM Now to fix the shield up and put it back in place. 17-Feb-20 12:01 PM Judging by how thick the shield is, the impact had to be at least a meter or two 17-Feb-20 12:11 PM really? it doesn't look that thick unless your hands are extremely big, and well its not aluminum like it looks like 17-Feb-20 12:12 PM that's stainless 17-Feb-20 12:12 PM 1mm thick 17-Feb-20 12:13 PM i see your postal service took lessons from Canada Post 17-Feb-20 12:13 PM The shield simply won't fit back on 17-Feb-20 12:13 PM It's too bent out of shape 17-Feb-20 12:14 PM at least stainless can be bent back without too much issue 17-Feb-20 12:14 PM lolno not this piece 17-Feb-20 12:14 PM I've been prying on it, it barely budges 17-Feb-20 12:14 PM well i mean if it was aluminum it would just snap after too much wiggling... 17-Feb-20 12:14 PM and yeah you might need to get creative with a vise or some blocks and a sledgehammer 17-Feb-20 12:15 PM I think I will design up and 3d print a shield for it 17-Feb-20 12:15 PM or that 17-Feb-20 12:15 PM the actual head has two bolt holes for this 17-Feb-20 12:15 PM anyone know a source for decent quality but cheap MHV connectors? looks like the options on aliexpress are a lot more expensive than ebay but almost all the ebay sellers are away until March 1st 17-Feb-20 12:15 PM ... and I have a nice shadow imprint to take measurements off 17-Feb-20 12:15 PM D: 17-Feb-20 12:15 PM I'm terrified of the Be window 17-Feb-20 12:16 PM i think we all are wishing you luck when you get around to inspecting the internals 17-Feb-20 12:16 PM and that seems justified 17-Feb-20 12:16 PM lol 17-Feb-20 12:16 PM there are no internals to inspect 17-Feb-20 12:16 PM oh no tube inside like the other? 17-Feb-20 12:16 PM what you see is what I can get to 17-Feb-20 12:16 PM besides pulling the tube out 17-Feb-20 12:16 PM but I REALLY don't want to do that 17-Feb-20 12:17 PM ahh i was not sure if you were going to or not with the bent up shield 17-Feb-20 12:17 PM I don't hear rattling inside 17-Feb-20 12:17 PM and no oil leaking through the window 17-Feb-20 12:17 PM which it would, since the oil would puncture the window if the tube leaked 17-Feb-20 12:17 PM but I'm still terrified of turning it on 17-Feb-20 12:18 PM do not blame you 17-Feb-20 12:18 PM double and triple check your pinouts 17-Feb-20 12:18 PM relying on what teckonstantin sent me 17-Feb-20 12:18 PM the only reason I bought this is because he reverse-engineered the pinout 17-Feb-20 12:19 PM yes i just mean make sure everything is connected right 17-Feb-20 12:20 PM gah this beryllium window is staring at me ominously 17-Feb-20 12:20 PM why does the best equipment have to have windows that can be destroyed by a hard sneeze 17-Feb-20 12:20 PM the hour meter is pegged beyond 10 000 lol 17-Feb-20 12:29 PM @Spirit you don't have a vise??? 17-Feb-20 12:29 PM nowhere to put one 17-Feb-20 12:29 PM take the piece where its bent and should be flat... and just crank it down in the vise 17-Feb-20 12:29 PM like... you need a vise 17-Feb-20 12:29 PM they are SO useful 17-Feb-20 12:29 PM I do, but I also need a place to put one 17-Feb-20 12:29 PM for fixing bent things 17-Feb-20 12:29 PM I fixed a 3/4" thick steel pin that got bent in a pallet jack... 17-Feb-20 12:29 PM some idiot rammed into the handle and bent the pin for the handle causing it not to really work right anymore 17-Feb-20 12:29 PM so yea, into the vise, got it straight enough 17-Feb-20 12:33 PM man I love working with metric hardware 17-Feb-20 12:33 PM from metric companies 17-Feb-20 12:33 PM after letting it sit I see a small oil spot in one place 17-Feb-20 12:33 PM not sure where that's coming from though 17-Feb-20 12:33 PM time to do some cad 17-Feb-20 12:56 PM spirit you need a random corner to pile heavy metal objects in 17-Feb-20 12:56 PM like a few vises of different styles, that plate you hammer stuff on, and those cut offs you are sure you will need someday 17-Feb-20 12:57 PM I agree 17-Feb-20 12:58 PM can't let these hobbies stay as a vice...gotta get vises into the mix 17-Feb-20 02:13 PM Judging by how thick the shield is, the impact had to be at least a meter or two @Spirit my eyes are already bleeding 17-Feb-20 03:08 PM update, thanks to Konstantin's guidance 17-Feb-20 03:08 PM pulled the tube out, it is 1) intact(I think) 2) so tiny and adorable 17-Feb-20 03:08 PM it must be only 50-60mm long in the glass section 17-Feb-20 03:08 PM bad news: the epoxy has been cracked at the impact site 17-Feb-20 03:08 PM good news: the oil only leaked a bit and I can fix the leak 17-Feb-20 03:10 PM congrats on your new score (tube wise at least) 17-Feb-20 03:10 PM to be honest if anything was broken I'd say it was the tube 17-Feb-20 03:10 PM the rest is solid epoxy and stainless 17-Feb-20 03:10 PM epoxy cracking seems like the absolute best case situation for that sort of drop damage 17-Feb-20 03:10 PM good grief yeah 17-Feb-20 03:10 PM I really hope the metal seal didn't break 17-Feb-20 03:10 PM the beryllium window has two tiny specks of dust on it but under high contrast light I don't see any cracks 17-Feb-20 03:12 PM i was really concerned you were going to end up with another shattered tube when you first posted the photos of the damage 17-Feb-20 03:12 PM so it being apparently intact is a win, i think...of course that could change 17-Feb-20 03:12 PM that was my concern too 17-Feb-20 03:12 PM the other tube is much bigger than this one 17-Feb-20 03:12 PM and it was poorly packed 17-Feb-20 03:12 PM so I suppose I'm a bit lucky here 17-Feb-20 03:12 PM IF it passes the high voltage test 17-Feb-20 03:12 PM but first I need to clean the crack out, derease it, and fill it with epoxy 17-Feb-20 03:13 PM what did the packing look like? was it really layers and layers of bubblewrap? 17-Feb-20 03:13 PM or do I go with high voltage silicone... hmmm 17-Feb-20 03:13 PM for this one? 17-Feb-20 03:13 PM how about both 17-Feb-20 03:13 PM tightly packed bubblewrap in an appropriately sized cardboard box 17-Feb-20 03:13 PM the other one... not so tightly packed bubblewrap 17-Feb-20 03:13 PM because I was the idiot directing the packaging 17-Feb-20 03:13 PM (never trust me to ship glass worldwide) 17-Feb-20 03:13 PM dang this stuff is the kind of thing where you go buy a sheet of styrofoam 17-Feb-20 03:13 PM i sold some old amps and had to charge a guy like $100 shipping ($40 in shipping supplies) just to make sure it got to him intact lol 17-Feb-20 03:50 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200218_024801-0D2CB.jpg 17-Feb-20 03:50 PM temporary sheet metal idiot(me) deterrent 17-Feb-20 03:50 PM Now to deal with cracked epoxy. 17-Feb-20 04:23 PM That the new microfocus tube? 17-Feb-20 05:55 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200218_045510-969E6.jpg 17-Feb-20 05:55 PM @Treehouseman yes 17-Feb-20 05:55 PM Also, new plan: 17-Feb-20 05:55 PM The crack kept leaking oil, a few uL per minute, thus I can't seal it 17-Feb-20 05:55 PM So... I took the tube out, took the baffle out, drained the oil(into a freshly cleaned container), and now I'm cleaning it 17-Feb-20 05:56 PM the oil for the HV section? 17-Feb-20 05:56 PM Yes 17-Feb-20 05:56 PM That's the tube housing 17-Feb-20 05:56 PM you can see the tiny channels that go to the baffle 17-Feb-20 05:56 PM (expansion) 17-Feb-20 05:56 PM bottom is the 100kv electrode 17-Feb-20 05:56 PM I will clean it, then feed acetone into the crack under vacuum, clean the crack out 17-Feb-20 05:56 PM then feed epoxy into it 17-Feb-20 06:33 PM After cleaning, ready for vacuum cleaning of the crack 17-Feb-20 06:33 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200218_053241-B1B77.jpg 17-Feb-20 07:25 PM Just the usual. Vacuuming my empty x-ray head 17-Feb-20 07:25 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200218_062450-EED45.jpg 17-Feb-20 07:25 PM Only moderate vacuum, to not upset things. Ethanol still visibly and quickly penetrates. And ethanol because it evaporates easily while dissolving this oil. 17-Feb-20 07:41 PM <__ice9#6039> Very thorough 17-Feb-20 07:41 PM Naw, the epoxy just wouldn't stick otherwise 17-Feb-20 07:42 PM <__ice9#6039> I probably would have just wiped it with acetone and covered it with hot glue, followed by epoxy, rather than disassemble completely. But obviously that is a lazy kludge and this method produces a much cleaner result. 17-Feb-20 07:43 PM it leaked too much too quickly 17-Feb-20 07:43 PM a few uL/min 17-Feb-20 07:45 PM <__ice9#6039> Couldn't just flip that side to be the top while repairing? No idea how the seals work tbf 17-Feb-20 07:48 PM that is the top 17-Feb-20 08:25 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200218_072515-493B0.jpg 17-Feb-20 08:25 PM Sealing under vacuum 17-Feb-20 08:25 PM Had a bit of sag at first but now it's solid 17-Feb-20 08:25 PM I think it's filled in completely now 17-Feb-20 08:25 PM Epoxy + TiO2 filler(pure), + Carbon (graphite powder) to keep the conductive coating outside 17-Feb-20 08:25 PM The crack was only on this side, but I covered the entire seal just to be sure 17-Feb-20 08:58 PM <__ice9#6039> Graphite-filled epoxy also works pretty well for thermal cement 17-Feb-20 08:58 PM <__ice9#6039> Much nicer than the foul-smelling kind from MG Chemicals 18-Feb-20 05:09 AM <__ice9#6039> https://www.weforum.org/agenda/2018/11/destroying-nuclear-waste-to-create-clean-energy-it-can-be-done/ Interesting article on accelerator-driven thorium reactor concepts. Not sure where this stands in terms of R&D atm. 18-Feb-20 05:42 AM https://twitter.com/GigaBecquerel/status/1229760662160781318?s=19 18-Feb-20 05:47 AM I... just... no words... 18-Feb-20 07:04 AM I saw a presentation by Muons inc. recently, who's working on an accelerator driven subcritical reactor 18-Feb-20 07:04 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/sstbSlide9-F35D0.png 18-Feb-20 07:04 AM http://public.muonsinc.com/Projects/AcceleratorDrivenSubcriticalReactors.aspx 18-Feb-20 07:04 AM They are quite far along the design phase already. The main attraction here is using up the weapons grade plutonium which will be essentially free from the government and also last a very long time 18-Feb-20 07:04 AM Though theoretically, it should be able to just burn natural uranium, DU, spent fuel... etc 18-Feb-20 07:04 AM Instead of a spallation neutron source, they have thought about using fusion neutrons as well 18-Feb-20 08:46 AM https://twitter.com/GigaBecquerel/status/1229807057257234432 18-Feb-20 10:59 AM delicious resolution 18-Feb-20 11:05 AM far from what it can do 18-Feb-20 11:05 AM plus this was just like 8 hours no shielding whatsoever 18-Feb-20 11:05 AM I should (might) get a proper mca on thursday 18-Feb-20 11:05 AM 8k channels! 18-Feb-20 11:07 AM and here i still need to wrestle better than 25% fwhm out of that NaI crystal, lol 18-Feb-20 11:07 AM cool :D 18-Feb-20 11:07 AM then I can set proper time constants for my detector and lower the noise 18-Feb-20 11:07 AM 25%? That sounds... yellow 18-Feb-20 11:08 AM i think it's just come unseated internally 18-Feb-20 11:08 AM this is with a detector I've built for a friend, 6.3% iirc 18-Feb-20 11:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D7E4D.png 18-Feb-20 11:08 AM it was crystal clear when i slapped it on.. but the PMT i'm using has a funky bulge and has a strange bit of optical coupling plastic shaped around to it that the prior owner had on a very yellow crystal 18-Feb-20 11:08 AM the crystal itself is shimmed into an aluminum tube that lives around the PMT and i think i never quite got it balanced on there 18-Feb-20 11:08 AM i might just ditch it and use duct tape 18-Feb-20 11:09 AM also ultrawide is awesome for spectroscopy 18-Feb-20 11:09 AM I see you've now transitioned to becqmoni 18-Feb-20 11:09 AM oh, the cathode / lense geometry might cause some weird internal reflections 18-Feb-20 11:09 AM ages ago 18-Feb-20 11:09 AM I've used theremino for like two days in total 18-Feb-20 11:10 AM what's the other thing you've been using? 18-Feb-20 11:10 AM other thing? 18-Feb-20 11:10 AM i'm using my canberra system 35+ for everything, 4k channels 18-Feb-20 11:10 AM oh you mean like, cumulatively two days 18-Feb-20 11:10 AM yeah 18-Feb-20 11:10 AM oh also i missed spirit's message completely derp 18-Feb-20 11:10 AM disregard me 18-Feb-20 11:11 AM hehe 18-Feb-20 11:11 AM I've got an ortec ISA card MCA and will be getting a PC for it 18-Feb-20 11:12 AM ooh 18-Feb-20 11:12 AM good luck finding software? 18-Feb-20 11:13 AM already got it ^^ 18-Feb-20 11:13 AM oh nice 18-Feb-20 11:13 AM as well as the canberra stuff, but no dongle :< 18-Feb-20 11:13 AM fun fact 18-Feb-20 11:13 AM if you don't use the dongle the newer versions will just tell you there's no MCA plugged in 18-Feb-20 11:13 AM damn that was a fun three days of debugging 18-Feb-20 11:14 AM oh, like a security dongle thing? 18-Feb-20 11:14 AM those are the worst 18-Feb-20 11:14 AM license 18-Feb-20 11:14 AM yeaah 18-Feb-20 11:14 AM yeah 18-Feb-20 11:14 AM ortec doesn't do that, but they use proprietary stuff like their dual port memory 18-Feb-20 11:14 AM dpm to usb cable for a cool 1.4k€ 18-Feb-20 11:15 AM zounds 18-Feb-20 11:15 AM but you'll get maestro (the software) for free with it, what a bargain! 18-Feb-20 11:15 AM MCAs seem like the right kind of place for weird proprietary high speed tech, which is kinda cool and kinda frustrating too 18-Feb-20 11:15 AM stuff like wilkinson ADCs 18-Feb-20 11:16 AM tbh I've never read anything about how MCAs actually work 18-Feb-20 11:16 AM I always assumed it's either peak detect and hold or just a really fast adc 18-Feb-20 11:16 AM cheapest off the shelf mca I found so far is som russian bodged together stuff that translates two ADC ports to ethernet 18-Feb-20 11:16 AM http://www.tgi-sci.com/tgi/nmcatb.htm 18-Feb-20 11:16 AM also lots of interesting stuff on that site 18-Feb-20 11:20 AM wilkinson ADCs are specifically designed for nuclear instrumentation, they are super linear and have very well defined bounds between each individual channel but they're comparatively much slower than sucessive-approximation ADCs (basically every kind of modern ADC used for anything else) 18-Feb-20 11:20 AM they also use a lot of power too apparently 18-Feb-20 11:22 AM with modern devices it's pretty much completely irrelevant 18-Feb-20 11:22 AM you take a 16 or 18 bit ADC and slice the top bits off to get 12 18-Feb-20 11:22 AM you get super high accuracy linear 12 bits 18-Feb-20 11:22 AM something like this 18-Feb-20 11:22 AM https://www.analog.com/media/en/technical-documentation/data-sheets/238618f.pdf 18-Feb-20 11:22 AM you eat the 2 LSBs and you get a clean 16b output, which is way beyond what you'd ever need 18-Feb-20 11:22 AM and at 10msps you can do peak detection in software if you have an adequate pulse shaper 18-Feb-20 11:27 AM @GigaSquirrel you should get/put together one of the arduino MCAs and shame its performance with your HPGe :D 18-Feb-20 11:27 AM kinda funny having a sensor with performance that drastically exceeds some of the stuff you could hook it up to 18-Feb-20 11:27 AM i've been on a similar kick with my tunnel diode pulser 18-Feb-20 11:28 AM I like that idea 18-Feb-20 11:29 AM I love that linear just says in their datasheet Ideally suited for a wide range of applications 18-Feb-20 11:29 AM that's like saying "Highly specialized for everything" 18-Feb-20 11:34 AM whaaaa 18-Feb-20 11:34 AM 120 bucks for an arduino MCA 18-Feb-20 11:34 AM https://www.youtube.com/watch?v=C7TwBUxxIC0 I wonder where he got the idea from 18-Feb-20 11:55 AM "one to five microsieverts, depending on what probe they were using" 18-Feb-20 11:55 AM this is infuriating XD 18-Feb-20 11:57 AM IT CLICKS THE DIAL SAYS THIS DOSAGE ITS GOTTA BE RIGHT 18-Feb-20 11:57 AM Personally I respect the video and what it trys to get across, the point is to try and get this stuff off the market and ya know what I feel it accomplishes getting that point across... 18-Feb-20 11:57 AM As for being scientific journal material... Well yea probably not. 18-Feb-20 11:58 AM Oh man... I'm gonna try and calibrate the free air ion chamber tomorrow, but not before putting it next to a running electron LINAC for a couple of hours 18-Feb-20 11:58 AM Hopefully it won't get destroyed, dose rate will be pretty high 18-Feb-20 12:01 PM ehehe 18-Feb-20 12:01 PM sounds like fun 18-Feb-20 12:06 PM He got help from Adam 18-Feb-20 12:06 PM Hopefully he tried to correct him :P 18-Feb-20 03:21 PM I believe my repair has been successful. 24V in, 236mA with the output enable signal off and voltage/current settings at 0. Filament started at around 2.5V, rose up to 3.07-3.08V and was stable there. That means it didn't burn out, so the tube is ok! 18-Feb-20 03:21 PM Filling it back with oil was HARD 18-Feb-20 03:21 PM Also, whatever high voltage oil hamamatsu use, it's magical. I pulled a full foreline vacuum on it and got 0 bubbles and 0 moisture. After it sat in air for many days. 18-Feb-20 03:21 PM If you want details on the oil, the name is "refined olive oil consistency, perfectly pee colored, smells like cancer" 18-Feb-20 03:21 PM Next up, getting a DAC and setting up three multimeters to measure voltage/current/error feedback 18-Feb-20 04:19 PM i discovered with my Aerovox capacitors that even if you can't get a hold of datasheets for your Thing anymore, getting MSDSes may actually prove to be much more fruitful 18-Feb-20 04:19 PM CD Aero (as they are now) had a Safety Records Guy that happily sent me an ancient scanned pdf of the MSDS for the dielectric in my caps, 'cos i wanted positive confirmation that they're not full of PCBs 18-Feb-20 04:19 PM if you care, might be worth an ask 18-Feb-20 04:19 PM (dioctyl phthalate, in my case. still kinda gross stuff, but not PCB gross) 18-Feb-20 04:21 PM well, it's done now 18-Feb-20 04:21 PM the tube is sealed and I don't intend on going in there ever again 18-Feb-20 04:22 PM fair :D 18-Feb-20 04:36 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/tube_1-90271.jpg 18-Feb-20 04:36 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/tube_2-74617.jpg 18-Feb-20 04:36 PM The Hamamatsu L7902 microfocus tube 18-Feb-20 04:36 PM 100kV, 200uA, and I think 10um focus. Or 15. Or 5. 18-Feb-20 04:36 PM The idiot shield added by me, to prevent it from ceasing to be an x-ray tube 18-Feb-20 04:36 PM The construction hasn't changed much since these older units - the dead 130kV 300uA tube I have is almost identical but 200% bigger 18-Feb-20 04:37 PM what is the little projection out of the window end? where they sealed it off or something? 18-Feb-20 04:38 PM The big or the small one? 18-Feb-20 04:38 PM the small one, the big one looks like it has a wire so i assumed it was a contact 18-Feb-20 04:38 PM The small one is the vacuum pip, the big one is the filament+cathode+grid(/s/?)+focusing grid 18-Feb-20 04:38 PM little one just seems out of place 18-Feb-20 04:38 PM ahh okay that is what it is, interesting little hat they put on it 18-Feb-20 04:39 PM It's covered in really white epoxy and has a hat 18-Feb-20 04:39 PM The hat is probably to protect it from opening 18-Feb-20 04:58 PM So, how long until you try to fire it up and see how it preforms? 18-Feb-20 04:58 PM I need to buy the parts first 18-Feb-20 04:58 PM this thing needs a beefy 24v supply(100W), and isolated(ish) 0-5V analog control voltages 18-Feb-20 05:42 PM spiffy :D 18-Feb-20 06:36 PM Just cobbled together a functional Ludlum Model 2 w/ 44-9 GM probe for my future sister-in-law's birthday. I'm going to help her level up her antiquing game. 18-Feb-20 06:36 PM That is a bit of a wild sentence but I fully approve 18-Feb-20 06:36 PM Side note: radiation pagers are awesome for flea market hunting 18-Feb-20 06:36 PM Sits discretely on your belt or in your pocket and will scream(or vibrate your whole body) at the slightest hint of radiation 18-Feb-20 06:37 PM They're touchy, but that's what you want. 18-Feb-20 06:38 PM Yeah, I have to adjust it a detection level higher if I go outside lol 18-Feb-20 06:38 PM The pavement sets it off 18-Feb-20 06:41 PM Future SIL has been doing some exceptionally good work at auctions and garage sales in Alaska. The Backwaters of Things, as you tend not to ship things back out of places like Alaska and New Zealand, means they've accumulated some treasures. As I demonstrated to her last time, she's accumulated a remarkable amount of furniture with uranium glass components. Kinda impressive really. 18-Feb-20 06:42 PM Hopefully no radium watches 18-Feb-20 06:43 PM Watches aren't really her thing, but my warning about Safe-At-Night radium paint accented items (so you don't run into them walking to the bathroom) from the 1930s did get her attention. 18-Feb-20 06:57 PM I beg to differ, yes radium watches 19-Feb-20 03:06 AM whoops 19-Feb-20 03:06 AM I may or may not have won five Hamamatsu R10467U-40 hybrid pmts on ebay 19-Feb-20 03:22 AM <__ice9#6039> I finally got around to measuring properly, and based on the gamma emission it appears my antique radium source is about 10μCi. This probably explains the lack of imaging practicality, though it's still nice to have this element in my collection. 19-Feb-20 09:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CB2BD.png 19-Feb-20 09:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-862FC.png 19-Feb-20 09:38 AM second one had to little current and to much stray light 19-Feb-20 09:38 AM but hey, seems like stuff is working more or less now 19-Feb-20 09:38 AM still cant adjust anything and the current control of the head is wired af so only max power for now 19-Feb-20 09:38 AM first image is an snm13 neuron counter 19-Feb-20 09:38 AM all visible to the naked eye using kodak intensifier sceen from an old casette 19-Feb-20 09:38 AM srsly need an enclosed cabinet tho, the stray radation is making any geiger i have scream, even though its just .2mA 19-Feb-20 09:44 AM What head are you using? 19-Feb-20 09:44 AM you also have a fair bit of backlighting, the detail improvement is much higher if you eliminate all light, I use my windowless bathroom for the setup 19-Feb-20 09:44 AM At the same time that second one looks like you're taking images offset at an angle to the screen? I found that xray interferance is minimal if you move the camera back a few feet and use a telephoto lens, lets me get dead on center with the screen and have no distortion in my images, makes processing much easier 19-Feb-20 09:44 AM I imagine it has a notable bit to do with the fact that in using a telephoto lens there's quite a bit of glass 19-Feb-20 09:49 AM i know, i aleady told there is much stray light ^^ 19-Feb-20 09:49 AM this was just for trying 19-Feb-20 09:49 AM on the second one the voltage control somehow also carped out so there was very little light from the screen, the exposure was 15s or so 19-Feb-20 09:49 AM the first one is allright 19-Feb-20 09:49 AM my plan in case i will continue using a screen is to just use a mirror, today i only took pictures for show and tell so it wasnt to important to me doing it right 19-Feb-20 09:49 AM The source is my PXS5-925 Microfocus 19-Feb-20 09:49 AM mostly in operational condition now, but im still not 100% happy 19-Feb-20 09:52 AM I just have a Siemens Heilodent MD dental head 19-Feb-20 09:52 AM I did the mirror thing, still caused me headaches 19-Feb-20 09:53 AM why? 19-Feb-20 09:53 AM getting alignment for removing distorsion before taking the picture so I didn't have to do it in post 19-Feb-20 09:53 AM if you're making a permenant setup it'll be fine 19-Feb-20 09:53 AM but mine is always temporary, I can't leave my xray setup on the bathroom counter and my dslr on a tripod in the shower 19-Feb-20 09:55 AM ah yes 19-Feb-20 09:55 AM i still hope ill get my dental sensor to work one day 19-Feb-20 09:55 AM I still need to get one 19-Feb-20 09:55 AM bu now i have to decide on ow to build the enclosure an/or control 19-Feb-20 09:55 AM what im doing at this point is allright for trying once but allways sitting next to it is not healthy 19-Feb-20 09:56 AM Here's my pictures I've gotten with my setup, you can see how the photo quality improved from the older posts https://id10t-tech.com/ 19-Feb-20 09:56 AM Yeah, that's the other thing I have to sort out 19-Feb-20 09:56 AM I need to get better shielding 19-Feb-20 09:56 AM 1.5mm is supposed to be legal 19-Feb-20 09:57 AM for dental? 19-Feb-20 09:57 AM but after i put 2mm in front of this thing and all detectors i have still max out i want more now 19-Feb-20 09:57 AM yes, for dental 19-Feb-20 09:57 AM pano and local 19-Feb-20 09:57 AM Would I need to shield around the head as well or only really downstream of the tube? 19-Feb-20 09:58 AM i think using the heliodent it should be fine without 19-Feb-20 09:58 AM actually even more insane 19-Feb-20 09:58 AM for the heliodent you legaly (in germnay) dont need shielding at all 19-Feb-20 09:58 AM there is a mandatory 1.5m distance to keep, then you can legaly operate it all day with no shielding 19-Feb-20 09:59 AM yeah, I have a remote activation button I use with it when I'm taking pictures 19-Feb-20 09:59 AM got like 10' of wire between me and the transformer, the head sits another foot or so beyond it 19-Feb-20 09:59 AM yes 19-Feb-20 09:59 AM sadly something i cant do 19-Feb-20 09:59 AM it needs to be preheated, continuously un for half a minute and then thecamera has to be activated 19-Feb-20 10:00 AM I still need to make a controller to activate the camera and head, right now I remote delay activate the camera, and then manually time the head, the head runs as long as I push the button 19-Feb-20 10:00 AM dont have a remote shutter 19-Feb-20 10:00 AM jup 19-Feb-20 10:01 AM if I make it automated I can minimize the on time 19-Feb-20 10:01 AM yes 19-Feb-20 10:01 AM that wont be ble to 19-Feb-20 10:01 AM not with that attitude 19-Feb-20 10:01 AM but i have 1/40 the current of the heliodent 19-Feb-20 10:01 AM I mean you totally can make a remote shutter 19-Feb-20 10:01 AM of cause i can 19-Feb-20 10:01 AM its just no use, im done with the first tests wich i had to see with my own eyes anyways 19-Feb-20 10:01 AM and now when i will have an enclosure i also dont need remote shutter 19-Feb-20 10:01 AM just a remote shutter will also not reduce the on time signifficantly in my case 19-Feb-20 10:01 AM its only good for not having to reach there 19-Feb-20 10:01 AM my source is CW operation only and needs a long time to get to powerlevels enough for imaging 19-Feb-20 10:05 AM interesting 19-Feb-20 10:05 AM is that normal for microfocus tubes? 19-Feb-20 10:05 AM seems to be 19-Feb-20 10:05 AM the cathode is indirectly heated 19-Feb-20 10:05 AM the manual states that the focus point will only be to spec after 10 minutes of continuous operation 19-Feb-20 10:07 AM hmm 19-Feb-20 10:07 AM and it only heats up when HV is on? 19-Feb-20 10:08 AM no, but HV also takes some time for some reason 19-Feb-20 10:08 AM not 10 minutes but if you just turn it on it arcs over on the inside 19-Feb-20 10:09 AM Wouldn't that be an indication of a weak and gassy tube? 19-Feb-20 10:09 AM if everything would work as supposed to be the current would be controlled by a grid like in a triode and this way very fast but for some reason its not working on mine 19-Feb-20 10:09 AM there is a ton of modifications inside and i still didnt figure out all of it 19-Feb-20 10:09 AM mh no, its arcing around the tube or inside of the PSU 19-Feb-20 10:09 AM The tube is a bit older but definitely allright 19-Feb-20 10:09 AM maybe even still some air bubble but i have different problems for now 19-Feb-20 10:15 AM not 10 minutes but if you just turn it on it arcs over on the inside @george can you hear air bubbles when you move the head in different directions? 19-Feb-20 10:15 AM xD 19-Feb-20 10:15 AM this head is filled with 25ml of oil 19-Feb-20 10:15 AM no bubble will moove 19-Feb-20 10:15 AM also thats the reason why its very difficult to fully degas 19-Feb-20 10:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/succ-43951.jpg 19-Feb-20 10:16 AM after long time they develop a small buble inside and if it is inside the Xray part it will arc over 19-Feb-20 10:17 AM i had it open and filled it myself ^^ 19-Feb-20 10:17 AM its just extremely difficult with this thing 19-Feb-20 10:17 AM construction wise its a nightmare 19-Feb-20 10:18 AM ok i did not find it very difficult to do 19-Feb-20 10:18 AM how did you do it? 19-Feb-20 10:18 AM sry, didnt realize you were you 19-Feb-20 10:18 AM you of cause know this one 19-Feb-20 10:19 AM tilting is often enough and if you don't want to pump you can close it up move the bubles to the membrane and fill the rest up 19-Feb-20 10:19 AM sry, didnt realize you were you @george 19-Feb-20 10:19 AM never tested the performance of SKYDD for such high voltage applications, might not be good enough 19-Feb-20 10:21 AM well, as you can see on the pic i did pump it 19-Feb-20 10:21 AM wasnt enough as it seems 19-Feb-20 10:21 AM oh, the oil is fine 19-Feb-20 10:21 AM it holds up once the voltage is there, in my experience fast transients will cause a lot of moovement in the oil and bubles will chain up 19-Feb-20 10:22 AM movent is not so good for negativ voltage also triple junction effects are a big problem 19-Feb-20 10:23 AM im pretty sure i just still have a bubble in there 19-Feb-20 10:23 AM i evacuated at least a dozend times to make sure but... 19-Feb-20 10:23 AM maybe i trapepd soemthing when putting back the membrane 19-Feb-20 10:24 AM with the normal oil bubbles are not a problem when they are in the other compartment 19-Feb-20 10:24 AM but they will moove between comparments 19-Feb-20 10:24 AM the two onnecting holes are pretty large 19-Feb-20 10:25 AM no 19-Feb-20 10:25 AM as i said, just running i never had any problems, only when turning on very fast 19-Feb-20 10:25 AM so it cant just be to weak oil 19-Feb-20 10:26 AM i have a head that is missing a lot of oil the membrane compartment is almost empty and it works fine 19-Feb-20 10:26 AM but no air in the membrane compartment i guess 19-Feb-20 10:26 AM the dead giveaway in my case is that this behavior is dependant on orientation 19-Feb-20 10:26 AM operated vertically i never had a single strike 19-Feb-20 10:27 AM a lot of i, can hear it when i tilt it "gluck gluck gluck" 19-Feb-20 10:27 AM only when running it horizontally 19-Feb-20 10:27 AM ouff 19-Feb-20 10:27 AM well, maybe ill try some other oil sme time 19-Feb-20 10:27 AM but for now im fine with it 19-Feb-20 10:27 AM bigger problems to solve 19-Feb-20 10:27 AM wrote to thermofisher bfor schematics but i doubt they will give me anything 19-Feb-20 10:28 AM they are quite tight also the software for the RS232 unit is unobtainable 19-Feb-20 10:30 AM joup 19-Feb-20 10:30 AM @GigaSquirrel told me to try but... 19-Feb-20 10:31 AM you always should, maybe you get to the right person 19-Feb-20 10:48 AM Nothing brightens up a Wednesday morning quite like a 2R/hr spent fuel sample on the SEM. 19-Feb-20 10:51 AM pics! 19-Feb-20 10:51 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CB8D8.png 19-Feb-20 10:55 AM mm mm mm mm mm, toasty :9 19-Feb-20 11:01 AM Cannot do pics 19-Feb-20 11:03 AM [crowd boos] 19-Feb-20 11:03 AM Give it a lick 19-Feb-20 11:04 AM [booing continues] 19-Feb-20 11:17 AM The fun part was demonstrating how much of student’s unknown source with 2R/hr field was beta. With “Okay, it is now less unknown. Put it away and redesign your experiment to cut beta.” 19-Feb-20 11:19 AM I filled mine by tipping it 90 degrees on the pip side, then injecting 5cc of oil, then pulling a vacuum on the membrane side, then injecting again and repeating until the channels filled up. Then I tilted it 20 degrees instead of 90, and kept injecting/vacuuming until the membrane compartment was also full. Then to 10 degrees, placed in the membrane, and filled through a small gap until it just overflowed a bit. No vacuum, just screwed down. @george 19-Feb-20 11:20 AM yep, as you can see in my picture i put a KF40 T on top 19-Feb-20 11:20 AM Oh, and I pre-filled it to the spring level before putting the tube in. That way it wouldn't form a bubble inside the tube cup 19-Feb-20 11:21 AM then filles it with an ecess of oil and evacuated multiple times keeping the entire membrane chamber under oil at all times 19-Feb-20 11:21 AM That wouldn't fully work I think 19-Feb-20 11:21 AM When I was pulling vacuum through the channels, it just blew all the oil into the membrane chamber 19-Feb-20 11:21 AM Leaving a bubble inside the tube chamber 19-Feb-20 11:21 AM I had to repeat the channel vacuum thing 3 times 19-Feb-20 11:25 AM but having 2-3cm of oil standding on top of the membrane chamber there is no way for new air to get in 19-Feb-20 11:25 AM oh, yours has channels in the middle? 19-Feb-20 11:25 AM pull a vacuum, have it bubble out, then let it suck evrything back 19-Feb-20 11:25 AM repeat multiple times, done 19-Feb-20 11:25 AM on the top corner 19-Feb-20 11:25 AM right behind the lid 19-Feb-20 11:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200218_045510-E3C47.jpg 19-Feb-20 11:25 AM but actually it shouldnt matter i think 19-Feb-20 11:25 AM yeah mine is here too 19-Feb-20 11:25 AM it would make a bubble on this side 19-Feb-20 11:26 AM yep, exactly the same 19-Feb-20 11:26 AM I have a feeling they're almost identical units 19-Feb-20 11:26 AM why would it? 19-Feb-20 11:26 AM a bubble in vacuum is no bubble if no new air can follow back 19-Feb-20 11:26 AM I don't know, but I would pour oil in, apply a vacuum to the membrane side, and suddenly there would be no oil inside the channels 19-Feb-20 11:26 AM Hamamatsu have all the patents on these heads, so I think kevex just licensed the whole design 19-Feb-20 11:27 AM no oil wouldnt mean air tho 19-Feb-20 11:27 AM yep 19-Feb-20 11:27 AM there was air 19-Feb-20 11:27 AM whre from? 19-Feb-20 11:27 AM after I removed the vacuum 19-Feb-20 11:27 AM aaaah 19-Feb-20 11:27 AM I didn't pull a very hard vacuum because mine was cracked and I repaired it 19-Feb-20 11:28 AM well, then you didnt have enough oil coverage or just let the air back in to fast 19-Feb-20 11:28 AM mh ok, partialvacuum sucks here (or not) 19-Feb-20 11:28 AM Believe it or not it doesn't 19-Feb-20 11:28 AM The oil Konstantin and I have is magical 19-Feb-20 11:28 AM Hamamatsu have all the patents on these heads, so I think kevex just licensed the whole design @Spiritkevex has the patents on most of the tube stuff, im not sure about the legal situation both seem to have similar patents 19-Feb-20 11:28 AM It simply does, not, absorb, air 19-Feb-20 11:28 AM Which is cool 19-Feb-20 11:28 AM @TecKonstantin Hamamatsu have all the patents too 19-Feb-20 11:29 AM jup both 19-Feb-20 11:29 AM That seems like a bit of a "prior art" issue :P 19-Feb-20 11:29 AM https://patents.google.com/patent/EP1158842A1/fi 19-Feb-20 11:29 AM they have tons of patents specifically for these tubes 19-Feb-20 11:29 AM But they also cite Kevex... so... 19-Feb-20 11:30 AM aaahhhhhh i have an idea for insulation oil 19-Feb-20 11:30 AM aeroshell 500 19-Feb-20 11:30 AM will try soon 19-Feb-20 11:30 AM fluorinert will work 19-Feb-20 11:30 AM maybe we should write a joint letter to Hamamatsu asking what oil they use for insulation 19-Feb-20 11:30 AM and then buy a barrel 19-Feb-20 11:30 AM it has insane ammounts of additives makin foaming almost impossible 19-Feb-20 11:31 AM additives = bad 19-Feb-20 11:31 AM for HV especially 19-Feb-20 11:31 AM Whoa, okay 19-Feb-20 11:31 AM https://patentimages.storage.googleapis.com/76/11/bc/e21d803ca6d95a/US5077771-drawings-page-16.png 19-Feb-20 11:31 AM This is almost exactly 1:1 from Hamamatsu, but way older 19-Feb-20 11:32 AM why bad? 19-Feb-20 11:32 AM maybe we should write a joint letter to Hamamatsu asking what oil they use for insulation @Spirit should be similar what is used in Stationary x ray transformer, but i never did the research 19-Feb-20 11:32 AM because impurities make breakdown easier 19-Feb-20 11:33 AM yes, but i doubt its anywhere close to critical 19-Feb-20 11:33 AM jump the patent situation is definitely very interesting 19-Feb-20 11:33 AM but arcover probably means you have bubbles, not bad oil 19-Feb-20 11:33 AM because even at 70-100kv, this amount of oil is total overkill 19-Feb-20 11:33 AM I've insulated against 100kv using 10mm of oil 19-Feb-20 11:33 AM exactly tahts what im talking about 19-Feb-20 11:33 AM oh, also 19-Feb-20 11:33 AM regarding the il im using at this time i just remembered 19-Feb-20 11:33 AM when i adapted the other standard tube to the microfocus supply i had to moove the anode connection very very close to the rim 19-Feb-20 11:33 AM there was less than 10mm insulation left and it still held up 19-Feb-20 11:33 AM forgot about that when i talked about oil the last time 19-Feb-20 11:35 AM I will be experimenting with that soon 19-Feb-20 11:35 AM I have a dead 130kv hamamatsu head 19-Feb-20 11:35 AM tube shattered, but psu should still be ok 19-Feb-20 11:36 AM aaah, fo sme reason i thought you also got a new tube for the broken head 19-Feb-20 11:36 AM I wish 19-Feb-20 11:36 AM ho did you get the other one? 19-Feb-20 11:37 AM the broken one? 19-Feb-20 11:38 AM wait 19-Feb-20 11:38 AM the hamamatsu was ebay i think? 19-Feb-20 11:38 AM im talking about the kkevex 19-Feb-20 11:39 AM both are hamamatsu 19-Feb-20 11:39 AM l9181-05(dead) and l7902(alive I think, hopefully) 19-Feb-20 11:40 AM sweet 19-Feb-20 06:34 PM <__ice9#6039> @george about that stray radiation-- lead sheets for x-ray shielding are pretty cheap, and you should definitely enclose the entire tubehead in them. 19-Feb-20 06:34 PM <__ice9#6039> Ordinary mineral oil is ok for insulation, but it works better if it's mixed with about 50% of another type of oil, checking notes.... 19-Feb-20 06:48 PM <__ice9#6039> Ah here we go 19-Feb-20 06:48 PM <__ice9#6039> Synthetic ester oils or ordinary vegetable oil can be mixed into transformer oil and produce significant increases in dielectric strength in proportions as low as 20% 19-Feb-20 06:48 PM <__ice9#6039> Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/signal-2019-11-02-152147-1-79CEC.png 19-Feb-20 10:41 PM Update: YES 19-Feb-20 10:41 PM IT WORKS 19-Feb-20 10:41 PM first test was at 12kV and 24uA(out of the 100kv/200ua capability), so that I wouldn't unnecessarily fry myself 19-Feb-20 10:41 PM my G1LE sensed it readily 19-Feb-20 10:41 PM also @Treehouseman can confirm - your G1LE will sense 12keV :P 19-Feb-20 10:41 PM a huge thanks to TecKonstantin for the ongoing help 19-Feb-20 10:41 PM it takes a really long time to get the output to work 19-Feb-20 10:41 PM over 5 seconds for the filament to heat up from standby temps 19-Feb-20 10:41 PM but once it gets going, hooo boy, this probe begs for mercy, even through a tiny slit in my protective window 19-Feb-20 10:46 PM fun 19-Feb-20 10:46 PM also, didn't you have some radiation pagers you linked a while back that you were interested in possibly selling? 19-Feb-20 10:50 PM merhaps 19-Feb-20 10:50 PM I have one or two, let me know how much you think it's worth to you in PM. 19-Feb-20 10:52 PM I'll be honest, I really have no idea what they're worth, all I know is it'd be what I'd want for hunting radioactive stuff when I'm out thrifting, rather than carring around a massive counter 19-Feb-20 10:52 PM that's what it's suited best for 19-Feb-20 10:52 PM I can get away with the GQC but the dosimeter with the G1LE is a bit excessive 20-Feb-20 12:01 AM <__ice9#6039> Yes it seems tube filaments usually take a couple seconds to heat up in general. 20-Feb-20 12:01 AM <__ice9#6039> And yes, counters absolutely scream when exposed to the output 20-Feb-20 12:01 AM <__ice9#6039> Recalling earlier calculations in this same channel for equivalent activity figures ended up in the high TBq to low PBq 20-Feb-20 12:11 AM But do the math 20-Feb-20 12:11 AM 12kV and 24uA input is absolutely nothing 20-Feb-20 12:11 AM that's what, 288mW input, 1% conversion(if that), 2.88mW x-ray output 20-Feb-20 12:11 AM 2.8mJ/s, at 20-Feb-20 12:11 AM actually, wait, that's a lot 20-Feb-20 12:11 AM that's 2.8mGy/s, or just over 1kR/hr 20-Feb-20 12:11 AM huh. 20-Feb-20 12:11 AM yep, that's a lot. 20-Feb-20 12:19 AM <__ice9#6039> ... yes. 20-Feb-20 12:20 AM "and that, kids, is why you do the math before telling someone to do the math" 20-Feb-20 12:21 AM <__ice9#6039> You may recall we did it for a full-scale tube a week or two ago, above. 20-Feb-20 12:21 AM yeah 20-Feb-20 12:21 AM either way I now have a good microfocus head 20-Feb-20 12:22 AM <__ice9#6039> Yeah congrats again on that ^^ 20-Feb-20 12:22 AM going to finish the control box, provide some interlock stuff 20-Feb-20 12:22 AM and then we get to find out if it can take more than 12kv 20-Feb-20 12:22 AM and then I get to buy a lot of lead to do the aging process 20-Feb-20 12:22 AM as I would like to avoid sitting under x-rays varying from soft-skin-burny to goodbye-fertility for a good 10 minutes 20-Feb-20 12:24 AM <__ice9#6039> Yeah I tried to warn someone else above about this problem as well. Said counters were triggering everywhere in the vicinity on 'leakage'. There should not be 'leakage'. Lead is a lot cheaper than chemotherapy. 20-Feb-20 12:25 AM someone seems to be selling soft lead for just under $2/kg 20-Feb-20 12:25 AM and it seems to be in thin sheet form 20-Feb-20 12:25 AM I'm going to buy 20-30kg 20-Feb-20 12:25 AM <__ice9#6039> Lol nice, I see this matches well with the American market 20-Feb-20 12:25 AM <__ice9#6039> Yeah I just received a nice lead sheet burrito rolled up in the mail 20-Feb-20 12:26 AM I wonder if I can control this x-ray head in "pulse" mode by setting the target current to 0... 20-Feb-20 12:26 AM I really don't want to keep cycling the filament in and out of standby 20-Feb-20 12:38 AM ...did you just translate W to Gy one to one? 20-Feb-20 12:38 AM as in 1 W x-ray translates to 1 Gy dose? 20-Feb-20 12:39 AM I've omitted the mass steps :P 20-Feb-20 12:39 AM it's not like you're going to pass your entire body through the target every second in a magical quantum manner 20-Feb-20 12:39 AM not a good estimate of the dose rate 20-Feb-20 01:56 AM ohhh something's happening 20-Feb-20 01:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7B376.png 20-Feb-20 02:09 AM Yeah I tried to warn someone else above about this problem as well. Said counters were triggering everywhere in the vicinity on 'leakage'. There should not be 'leakage'. Lead is a lot cheaper than chemotherapy. @__ice9 I suggest you compare to mediacal xray. Just for simple resoning, the standard machine here is the Heliodent 70, 70kV tungsten target, 8mA, .2-.5s per picture. You sit directly in the beam and absorb a lot of it. Microfocus like mine: 70kV tungsten target, 200uA max, sitting behind it while (of cause the sides are lead shielded, why do you all assume im a retard here?) running it for a minute at a time. Just by those numbers you can see, even if i sat right in the beam looking at the window, getting blasted right in the face at full tube current i would have just one small dental xray every 20s. Of cause not taking in account geometry, but it will not change these numbers much. 20-Feb-20 02:09 AM And now consider im actually not sitting in the beam but sideways or behind 20-Feb-20 02:09 AM the stray and reflected radiation is several orders of magnitude less 20-Feb-20 02:09 AM Also consider CT-scans wich are roughly the border of medically acceptable doses 20-Feb-20 02:09 AM thats minutes of 80-120kV @ 50mA 20-Feb-20 02:09 AM absorbed all over your body 20-Feb-20 02:13 AM I agree with @george here, you've all told him your safety concerns. Just leave it at that. Stick to technical discussions here and stop turning this into a "Let's tell people what they must not do" channel. 20-Feb-20 02:14 AM If its actually with a reason, if someone is endangering anyone (including himself) im fine with it of cause 20-Feb-20 02:14 AM but the level of "u stupid, get lead" with no actual thinking or calculating behind it is a little anoying 20-Feb-20 02:15 AM "just leave it at that" was also meant for you 20-Feb-20 02:15 AM still on topic 20-Feb-20 03:34 AM <__ice9#6039> I didn't say that, meant no harm whatsoever by what I did say (suggesting more shielding), and was merely doing my best to comply with the new update to the #welcome channel by Adam. I do not think comparing against health-required medical procedures is an appropriate benchmark, and I believe that current regulatory guidance on shielding in applicable use cases is consistent with this view. I have nothing further to say. 20-Feb-20 03:34 AM <__ice9#6039> on a more useful note: worth pointing out that non-conductive fluids like mineral oil can serve as an effective liquid cooling agent in high voltage circuits-- depending on compatibility with cooling loop materials 20-Feb-20 03:58 AM <__ice9#6039> A few other options-- https://en.wikipedia.org/wiki/Liquid_dielectric 20-Feb-20 03:58 AM <__ice9#6039> refined castor oil is another compelling option-- better compatibility with silicone tubing for instance, though viscosity is considerably worse 20-Feb-20 03:58 AM <__ice9#6039> apparently Castrol took its name from castor oil 20-Feb-20 04:05 AM Well, in regard of safety guidlines actually im within. Dental X-Ray by the most recent rules in germany (and i doubt it will be dramatically more strict anywhere else) allow personel to use dental x-ray equipment with no shielding whatsoever if a distance of 1.5m is kept 20-Feb-20 04:05 AM <__ice9#6039> I said I have nothing further to say. 20-Feb-20 04:05 AM now THAT is something i would not consider safe for occupation 20-Feb-20 04:05 AM and im below that. 20-Feb-20 04:05 AM Im sorry you are offended now, but after your replied what you replied i think i have to make my point more clear 20-Feb-20 04:05 AM i dont like to be treated like an idiot for not going insane with safetymeasures 20-Feb-20 04:05 AM just as im an opponent of using more safetygear in labs than needed 20-Feb-20 04:05 AM it leads to people not seeing actual danger 20-Feb-20 04:05 AM I believe in science and statistics and i know what im doing is well well below anything dangerous even on an occupational daily level, so i dont see why i should change anything 20-Feb-20 04:10 AM <__ice9#6039> I did no such thing, and again, I have nothing further to say. Please drop the subject as requested by others above.... 20-Feb-20 04:11 AM Yeah I tried to warn someone else above about this problem as well. Said counters were triggering everywhere in the vicinity on 'leakage'. There should not be 'leakage'. Lead is a lot cheaper than chemotherapy. @__ice9 20-Feb-20 04:11 AM If that wasnt latently offensive i dont know what is 20-Feb-20 04:11 AM i will stop now for the sake of others 20-Feb-20 04:11 AM but it really sad how this place is turning from open minded talking into fusorforums 2.0 20-Feb-20 04:20 AM <__ice9#6039> debatable. but disinclined to debate it. 20-Feb-20 10:06 AM Does anyone happen to know the hole diameter for the type C connector on Ludlum detectors? Don't have one yet but the info would help for planning purposes 20-Feb-20 10:24 AM @GigaSquirrel 20-Feb-20 10:25 AM uhm 20-Feb-20 10:25 AM they're 3/8-32 iirc 20-Feb-20 10:25 AM like the regular BNC thread 20-Feb-20 10:25 AM at least in my older models they are 20-Feb-20 10:55 AM Thanks 20-Feb-20 10:55 AM guess the MHV bulkhead jacks i was looking at would not be a good idea then...think they have 1/2-28 threads 20-Feb-20 11:02 AM you can also just get an adapter to whatever you want 20-Feb-20 11:02 AM I got a type C to BNC adapter incase I want to hook up something not type C to my ludlum 20-Feb-20 11:03 AM i do not have any plans to use type C connectors on anything so it would be more expensive to get an adapter than just swap out the jack 20-Feb-20 11:04 AM just throw some BNC in there 20-Feb-20 11:04 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200220_145943-223CD.jpg 20-Feb-20 11:04 AM good bye soundcard spectroscopy, I will not miss you! 20-Feb-20 11:04 AM want the option to use it for He3 tubes so i was going for MHV...but BNC would probably be alright 20-Feb-20 11:04 AM congrats on the spectroscopy setup! 20-Feb-20 11:05 AM the He doesn't care about the connector you're using 20-Feb-20 11:05 AM thanks ^.^ 20-Feb-20 11:05 AM 2kV cares 20-Feb-20 11:05 AM nope 20-Feb-20 11:05 AM not at all 20-Feb-20 11:05 AM good BNC cables work perfectly fine up to ~3 kV 20-Feb-20 11:05 AM oh really? i was told that bnc start having issues with arc over at around 1500V 20-Feb-20 11:06 AM I just kept my type C on because I got a probe thats type C with the cable with the meter... 20-Feb-20 11:06 AM so... 20-Feb-20 11:06 AM easier that way 20-Feb-20 11:12 AM just checked BNC specs and Amphenol say: "Dielectric Withstanding Voltage 1500 VRMS " meanwhile the recommended operating voltage for one of my tubes is 2400V 20-Feb-20 11:12 AM think I am better off not trying to squeak by with BNC on that 20-Feb-20 11:13 AM shrug 20-Feb-20 11:13 AM works fine with my stuff 20-Feb-20 11:14 AM yeah i have just BNC on my geiger tubes and NaI(Tl) but i do not want to push my luck past 1500V 20-Feb-20 12:41 PM ohh boi 20-Feb-20 12:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5FA6F.png 20-Feb-20 12:41 PM it resolves the 109 and 112 keV peaks of the two U isotopes! 20-Feb-20 12:41 PM it is 20-Feb-20 12:41 PM nah, this is a terrible HPGe 20-Feb-20 01:32 PM oh that's exquisite 20-Feb-20 01:32 PM ya'll know what that means? 20-Feb-20 01:32 PM I can now determine... enrichment 20-Feb-20 02:05 PM guess who forgot to refill their hpge under all the excitement of finally having a good HPGe setup 20-Feb-20 02:05 PM but I just saw it switch to "warm", should be cold again in like half an hour 20-Feb-20 02:05 PM https://www.mirion.com/products/cryo-cycle-ii-hybrid-cryostat 20-Feb-20 02:05 PM Around 2003 we developed a really innovative product that we called a hybrid cryostat. This unit was dubbed “The Ever-Ready” for a short time before a certain battery company objected rather strenuously whereupon we changed the name to The Cryo-Cycle. Using a compact Stirling Cooler built into a custom Dewar assembly we are able to re-condense the nitrogen boil-off gas and thus operate virtually indefinitely without adding liquid nitrogen. In case of power failure the unit will provide cooling for 10 days or so until power can be restored. It will even make liquid nitrogen from nitrogen gas if needed. This has been a very popular product easily outselling all the previous generations of electric coolers combined. 20-Feb-20 02:22 PM that's not their product description 20-Feb-20 02:22 PM that's a one man product of someone who worked there 20-Feb-20 02:48 PM I'm curious if the radiation pager I just bought will pick up the dental office nextdoor at work when they take an xray 20-Feb-20 02:48 PM might be a fun way to torment my coworkers 20-Feb-20 02:48 PM excellent, it'll be a nice fun way to horrify them that they've been working there for years lol 20-Feb-20 03:12 PM ??? your telling me you'll pick up xrays from a modern xray machine, through probably two walls and (should be shielding) not to mention the xrays should be going through someones face too? 20-Feb-20 03:12 PM That just seems... wrong? 20-Feb-20 03:12 PM I mean pick them up in the same room if your like near the output with the thing, yea 20-Feb-20 03:16 PM yeah, I'm sure it'll be well into the "whatever" range, but as long as it makes it happy I can use it to scare my coworkers because they still refuse to believe me when I say it's negligable 20-Feb-20 06:13 PM Where in American are you such that the state public health agency lets that fly? 20-Feb-20 08:10 PM https://twitter.com/cnlohr/status/1230700854442774528 20-Feb-20 08:28 PM smh That guy. Sigh. 20-Feb-20 08:29 PM Charles or Nile? 20-Feb-20 08:35 PM Charles Red Nile is more a matter of “how in the nether heck did you get ANY of this?” 20-Feb-20 08:35 PM The opening two minutes reveal a staggering lack of knowledge before diving into playing with respirable, bioavailable heavy metals. The radioactive part is almost irrelevant. 20-Feb-20 08:51 PM united nuclear sells it 20-Feb-20 09:12 PM I am well aware. 20-Feb-20 09:12 PM That is not a ringing endorsement. 20-Feb-20 09:32 PM <__ice9#6039> @LRM in related news, MHV connectors melt when inadvertently exposed to 20kV 20-Feb-20 09:32 PM <__ice9#6039> Longer plastic bayonet connectors become necessary, ideally with dielectric grease 20-Feb-20 09:55 PM <__ice9#6039> BNC rating is 500V_RMS. Stated dielectric withstand test voltage is 1500V_RMS. 20-Feb-20 09:55 PM <__ice9#6039> So it could definitely go higher for pulses, but I wouldn't want to use it for bias at that voltage. 20-Feb-20 09:55 PM <__ice9#6039> Arc distance in air at 3kV is 1mm by Paschen, but in practice corona will lengthen it a little bit. 20-Feb-20 09:55 PM <__ice9#6039> (just an indicative figure, gives some sense of the range at which arcover becomes plausible without grease) 20-Feb-20 09:55 PM <__ice9#6039> >This unique capability provides the convenience of operating a detector for 12 to 18 months before LN2 needs to be added, but at the same time keeps the detector cold in case of power failure.  @GigaSquirrel this is wonderful-- is it self-contained as well...? 20-Feb-20 10:03 PM yep i was figuring that it would be totally fine based on the air breakdown distance to use the BNC stuff i have on hand...but why push it if i do not really have to... 20-Feb-20 10:04 PM <__ice9#6039> Ah it is self-contained! I have only seen a few like this. Missed an eBay auction for one a year or so ago and haven't seen another one since. 20-Feb-20 10:04 PM <__ice9#6039> No listings, though. Probably very costly through means other than surplus ^^ 20-Feb-20 10:04 PM <__ice9#6039> Hmm NileRed usually uses reasonable safety equipment from what I have seen in passing, but I've only watched 2-3 of his videos so idk. I did give him some pointers on joint sealant for strong acid distillation on Twitter a while ago though. 20-Feb-20 10:04 PM <__ice9#6039> If you need a lot of nitric acid for metalwork and ceramics processing, it is cheaper to distill it yourself from conc H2SO4 and KNO3/NaNO3. Ironically it's easier to make fuming than azeotropic, but note this imposes substantial additional storage requirements and precautions. FEP bottles strongly encouraged. 20-Feb-20 10:04 PM <__ice9#6039> HNO3 is also very useful for uranium/thorium chemistry. 20-Feb-20 10:04 PM <__ice9#6039> Do not store fuming acids in glass bottles if possible. Use secondary containment if you must. 20-Feb-20 10:16 PM his biggest bad lab practice examples seemed to be in the uranium glass video from what i have noticed 20-Feb-20 10:16 PM <__ice9#6039> Oh lol I haven't actually seen it 20-Feb-20 10:16 PM <__ice9#6039> Googling presently.... 20-Feb-20 10:16 PM the yellow cloud of dust made me very uncomfortable 20-Feb-20 10:16 PM think there is a link in #show-and-tell 20-Feb-20 10:18 PM <__ice9#6039> Ah yeah I found it hmm 20-Feb-20 10:18 PM <__ice9#6039> So he's right that dissolving most refractory oxides into silicate glass melts directly is usually impractical or very tedious, and he's right that using sodium salts of an oxide cation of the target element is usually easier 20-Feb-20 10:18 PM <__ice9#6039> That's also the basis for using sodium silicate for instance 20-Feb-20 10:18 PM <__ice9#6039> Watching more.... 20-Feb-20 10:20 PM my biggest gripes were 1) his obvious initial lack of understanding about uranium being an alpha emitter and getting that first geiger counter 2) the yellow cloud 20-Feb-20 10:20 PM <__ice9#6039> Beta emissions aren't going to make it through that container for the most part. That's mainly gamma. 20-Feb-20 10:20 PM <__ice9#6039> Lol yeah I see you caught it too 20-Feb-20 10:20 PM the second choice wasnt too great either but at least it was a pancake probe 20-Feb-20 10:20 PM those mazur geiger counters are so overpriced for what they are 20-Feb-20 10:21 PM <__ice9#6039> Yep have seen them 20-Feb-20 10:21 PM <__ice9#6039> I built an alpha probe with a Russian mica tube and then later bought some proper equipment 20-Feb-20 10:21 PM <__ice9#6039> Surplus as usual ^^ 20-Feb-20 10:22 PM yeah my favorite tubes are my soviet surplus ones 20-Feb-20 10:22 PM <__ice9#6039> Cleaned off some ugly surface oxidation on the chassis/handle, good as new 20-Feb-20 10:23 PM the SBT-10A tubes are really versatile if you protect the mica 20-Feb-20 10:23 PM need to make a better case for it...used some extra pink plastic i had from around when i first got my 3d printer 20-Feb-20 10:23 PM half considering just getting some hello kitty stickers to make it totally absurd 20-Feb-20 10:24 PM <__ice9#6039> Lmao what 'directly throw uranyl nitrate into molten glass' 20-Feb-20 10:24 PM <__ice9#6039> I guess if you want a face full of hot nitric acid and NOx 20-Feb-20 10:27 PM i hope that bit was mostly a joke...i hope 20-Feb-20 10:27 PM i wonder if uranyl nitrate goes pop like many nitrates do when heated 20-Feb-20 10:27 PM what a mess that would make haha 20-Feb-20 10:29 PM <__ice9#6039> Stir bar part is a little silly also tbf, should have checked the temperature dependent solubility of the compound. Sometimes they need to be heated or cooled to speed up dissolving. And sometimes you need to stir them for several hours that way. 20-Feb-20 10:29 PM <__ice9#6039> I don't see why it wouldn't. 20-Feb-20 10:29 PM <__ice9#6039> Residual nitrates in ceramics cook off like that when fired too, nice nitric acid aroma 20-Feb-20 10:29 PM <__ice9#6039> Finding temp dependent solubility curves is sometimes surprisingly time consuming. Usually they will appear in old books of reference tables 6000 pages long. But they usually do exist. Meanwhile googling will just get you a dozen pages of irrelevant recent research papers on composites and nanoparticles and whatever else but the basic ordinary substance itself. 20-Feb-20 10:29 PM <__ice9#6039> Huh that filtration left a lot of uranium-contaminated media. Better to just dump into a bigger beaker and try harder. 20-Feb-20 10:41 PM <__ice9#6039> The Na2U2O7 preparation looked pretty clean, and I agree with the approach of desiccation in the final container-- but in this case that probably should have been the melting crucible rather than a jar 20-Feb-20 10:41 PM <__ice9#6039> Not necessary to blend the boric acid though. Give it long enough and it will melt just fine. Wouldn't recommend using a silica crucible to make glass though. SiC graphite is a better choice. 20-Feb-20 10:41 PM <__ice9#6039> Lol that cloud 20-Feb-20 10:41 PM <__ice9#6039> Forbidden Cheeto dust 20-Feb-20 10:41 PM <__ice9#6039> Anyway that wouldn't have happened if one were to use the crucible to do the desiccation (... which can be done in the furnace directly if temp is increased slowly enough) 20-Feb-20 10:41 PM <__ice9#6039> Actually in this case most of the reagents could have been included together in solution and suspension (as the case may be), then co-precipitated/dried in the final container. This is how catalyst media is usually made. 20-Feb-20 10:41 PM <__ice9#6039> Ah cool, the temp dependent fluorescence is very interesting 20-Feb-20 10:41 PM <__ice9#6039> Forgot to anneal it though hmm 20-Feb-20 10:41 PM <__ice9#6039> ... yeah the annealing needs to be done in a separate bake or during initial cooling in the first place. Was probably already below the annealing point by the time the insulation was placed on top outside the furnace. 20-Feb-20 10:41 PM <__ice9#6039> Ok so now we have uranium glass powder all over everything 20-Feb-20 10:41 PM <__ice9#6039> Hmm. 20-Feb-20 10:41 PM <__ice9#6039> I see the concerns with this one. 20-Feb-20 10:41 PM <__ice9#6039> In case it wasn't clear: glass and ceramics pretty much always need to be annealed after initial production of the object, unless you are intentionally trying to temper them. 20-Feb-20 10:41 PM <__ice9#6039> Only one furnace, hmm well: there is a solution to that ^^^^^^ 20-Feb-20 11:00 PM tonight in eBay mysteries... 20-Feb-20 11:00 PM https://www.ebay.com/itm/RADIATION-PROBE-LUDLUM-OR-EBERLINE/362591832325 20-Feb-20 11:00 PM https://www.ebay.com/itm/RADIATION-PROBE-LUDLUM-OR-EBERLINE-2/192864959653 20-Feb-20 11:00 PM first one has some amphenol 10 pin connector 20-Feb-20 11:00 PM second one has what looks like a tube base (pmt?) 20-Feb-20 11:00 PM seller did not like my offer of $100 shipped for both of them heh 20-Feb-20 11:00 PM figured that was almost fair given the total lack of any kind of markings 20-Feb-20 11:03 PM <__ice9#6039> Meanwhile seller has no idea what they even are lol 20-Feb-20 11:03 PM exactly 20-Feb-20 11:03 PM one has to wonder how "reliable" this source is if they have mystery equipment 20-Feb-20 11:04 PM <__ice9#6039> I agree the second one is almost certainly a PMT attached to a scintillator in a mag shielded canister 20-Feb-20 11:04 PM <__ice9#6039> I am at a loss as the pinout of the first one though 20-Feb-20 11:04 PM i spent a bit of time looking last night to see if i could come up with anything based on the connector but no dice 20-Feb-20 11:04 PM it is a 62IN series in the 12-10 pin layout 20-Feb-20 11:06 PM <__ice9#6039> Hmm anyway, some procedural imperfections aside: I know how to make uranium glass now. So I still like NileRed. Seeing something done once, even with a few correctable errors, is better than not seeing it at all. 20-Feb-20 11:06 PM <__ice9#6039> NurdRage is also pretty good. A few others exist as well. 20-Feb-20 11:08 PM definitely agree there that it was neat to see it done, but i already knew how... 20-Feb-20 11:08 PM <__ice9#6039> But yeah trying to find a probe based on just the connector type is probably pretty hard hmm 20-Feb-20 11:08 PM could not even find any products by ludlum or eberline that even use that connector 20-Feb-20 11:08 PM or a couple other brands 20-Feb-20 11:08 PM <__ice9#6039> Yeah I don't own anything like that one either 20-Feb-20 11:08 PM <__ice9#6039> May have been custom for some lab 20-Feb-20 11:09 PM probably...the one with that amphenol connector looks pretty well sealed up too 20-Feb-20 11:09 PM hopefully just with epoxy/glue 20-Feb-20 11:09 PM <__ice9#6039> Lol you can always use the 'message' field to poke them 20-Feb-20 11:09 PM i tried! theyre ignoring me or something heh 20-Feb-20 11:09 PM and actually looking at that image closer 20-Feb-20 11:09 PM think that detector is welded shut 20-Feb-20 11:10 PM <__ice9#6039> X___x 21-Feb-20 04:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200221_133828-A9D60.jpg 21-Feb-20 04:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200221_134209-28869.jpg 21-Feb-20 04:43 AM good thing this all wasn't heavy af and terrible to get to 21-Feb-20 04:43 AM but the 2 cm of lead are already an awesome Reduktion in Background 21-Feb-20 04:43 AM can't wait for my actual 10 cm 21-Feb-20 08:09 AM ooo! 21-Feb-20 08:09 AM how hard is that gonna be to refill if it's all mounted up in there like that? 21-Feb-20 08:09 AM guess i don't see how it fastens up there 21-Feb-20 08:11 AM the red Line is fill, white is vent ^^ 21-Feb-20 08:11 AM connected it to a big dewar of mine, pressurize it with 500 mbar and it fills the detector regardless of Position 21-Feb-20 08:11 AM btw, I need to redo the plug for my filling dewar 21-Feb-20 08:11 AM when the liquid flows through it it shrinks enough to leak around the outside 21-Feb-20 08:11 AM who could have guessed shrinkage becomes a problem at -200°C 21-Feb-20 08:27 AM ...lol 21-Feb-20 08:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200221_165051-44C87.jpg 21-Feb-20 08:27 AM I was wondering where the ~509 keV peak in my lutetium spectrum came from 21-Feb-20 08:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200221-172641-C5563.png 21-Feb-20 08:27 AM it's a summing peak! 21-Feb-20 10:33 AM ooo 21-Feb-20 10:53 AM Impressive 21-Feb-20 09:21 PM wow the Ludlum model 12 units that guy had really are old...but i am kinda glad i decided to risk them all being dead. 21-Feb-20 09:21 PM the one that seems to work pretty well (not sure why it was marked as having issues on the x1 scale) also came with a cool bonus 21-Feb-20 09:21 PM https://i.gyazo.com/309b7c7ffdb6e874606ec183bbc0004c.jpg 21-Feb-20 09:21 PM never seen that Y-12 logo before 21-Feb-20 09:21 PM less than $60 shipped for 3 super ancient model 12 meters, especially when one comes with that sticker, isn't so bad 21-Feb-20 11:20 PM dang that's pretty cool 21-Feb-20 11:32 PM any guesses as to what the two lines and two arrows are supposed to represent? enrichment maybe? 21-Feb-20 11:34 PM SNM is "Special nuclear material" 21-Feb-20 11:34 PM so yeah, fussion stuff 21-Feb-20 11:34 PM Y12 was doing enrichment iirc 21-Feb-20 11:35 PM yeah i knew the SNM thing already...just was curious about what was behind the logo 21-Feb-20 11:35 PM can't find any info about that Y-12 logo at all and it is kinda tape so i am kinda wondering if they used that to tape boxes closed or something... 21-Feb-20 11:56 PM maybe @funranium can shed some light on this? 22-Feb-20 12:57 AM I cannot shed any additional light on this. 22-Feb-20 02:01 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200222_110024-715D8.jpg 22-Feb-20 02:01 AM @george wearing 2mm of lead aprons 22-Feb-20 02:50 AM oh cool symbols 22-Feb-20 02:50 AM also woo upper body workout :D 22-Feb-20 06:28 AM I'd love to get ahold of some 2mm aprons for a reasonable price but all I've been able to justify buying is some 0.5mm garments 22-Feb-20 07:41 AM I mean you can have a .5mm one 22-Feb-20 07:41 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200222_161751-4BC31.jpg 22-Feb-20 07:41 AM more cooking! 22-Feb-20 08:30 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200222_172456-72F9A.jpg 22-Feb-20 08:30 AM hybrid PMTs ❤️ 22-Feb-20 10:27 AM nice finds! 22-Feb-20 10:27 AM what are you planning to pair them with? 22-Feb-20 10:34 AM There are a lot of treasures here this morning. 22-Feb-20 10:44 AM I have no idea yet, they were just waaaay too cheap to pass 22-Feb-20 12:58 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200222_215726-8AE12.jpg 22-Feb-20 12:58 PM heh, by chance it was the perfect amount 22-Feb-20 02:25 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200222_232233-E3441.jpg 23-Feb-20 03:48 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200223_124515-39885.jpg 23-Feb-20 03:48 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200223_124522-94C7B.jpg 23-Feb-20 03:48 AM magnet! 23-Feb-20 03:48 AM with some impressive thermal capacity 23-Feb-20 04:19 AM goddamn relativstic stuff 23-Feb-20 04:19 AM at 50 mT an electron would have to go 3.81 times the speed of light to fly a 13 cm radius 23-Feb-20 05:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200223_141449-22CF4.jpg 23-Feb-20 05:31 AM I kinda wanna build a betatron now 23-Feb-20 05:31 AM too bad (or actually good) that I have zero glassblowing skills 23-Feb-20 05:31 AM 'tho maybe if I made the vacuum chamber out of metal apart from like a small insulator... 23-Feb-20 08:17 AM https://www.youtube.com/watch?v=42qJoh-OIJ4 23-Feb-20 08:17 AM Damn those magnets are fun 23-Feb-20 01:03 PM https://www.youtube.com/watch?v=7ZUqSncJ5U0 23-Feb-20 01:03 PM ayyy 23-Feb-20 01:35 PM his uranium glass video, and this cleanup one, leaves me wondering how much other safety related stuff he does that i just have not noticed... 23-Feb-20 01:35 PM also his strategy of everything in a container and finding someone to take care of it later seems...iffy 23-Feb-20 01:57 PM mostly his lack of contamination testing is what bothers me 23-Feb-20 01:57 PM the little rad chemistry I've done was all with continued monitoring using a big area detector 23-Feb-20 04:48 PM I agree. He should get himself a proper counter with the various counter tubes and filters to figure out what’s what and where it is getting. 23-Feb-20 04:48 PM If he wants to continue working with this stuff anyways. 23-Feb-20 04:48 PM Also generally the glassware used to prepare the various things would normally just be melted down and disposed of that way 23-Feb-20 05:49 PM For me, as the health physicist, I’m not even particularly worried about the radiological aspects here. It is the rather messy work with chemical forms of uranium that have higher bioavailability for heavy metals work. 23-Feb-20 05:49 PM Admittedly, having a meter helps find all the mess you made and clean it up afterward. 23-Feb-20 07:53 PM I was kinda concerned about the assumption he made that his detector was giving anything approaching a real dose rate reading in his first video 23-Feb-20 09:03 PM Yes. Bioavailability is really the concern. Heck metallic mercury is really not that dangerous but if it’s methylated it can kill you before you hit the floor. Aqueous uranium solutions made me feel a bit uneasy. More than just powdered stuff. 23-Feb-20 09:03 PM Even though powdered has inhalation risk 23-Feb-20 10:37 PM the risk of inhaling a fairly strong alpha emitter was my main concern with his yellow cloud but the whole heavy metal nature of uranium has its risks too especially in solutions 23-Feb-20 10:37 PM plus the total inadequacy of the first geiger counter he got that betrays some lack of understanding 23-Feb-20 11:27 PM @Addison-110m what do you mean by standard size? The most common dewars are 30l 23-Feb-20 11:28 PM Most of the detectors I've seen have the same size dewar on them but I realized I never bothered to check what size that was 23-Feb-20 11:29 PM ah, right 23-Feb-20 11:30 PM Yeah, the skepticism on refill rates is off of experience with the two that I'm around at work 23-Feb-20 11:31 PM I've seen as low as a week, but at that point the dewar is really starting to sweat 23-Feb-20 11:31 PM surprisingly few people consider just repumping their dewars 23-Feb-20 11:31 PM (and detectors!) 23-Feb-20 11:32 PM Don't get me started on that second one 23-Feb-20 11:34 PM oh geez 23-Feb-20 11:34 PM but now I kinda want to :D 23-Feb-20 11:35 PM I heard of somewhere with a large shelf of dead HPGe detectors 23-Feb-20 11:35 PM No one having even half an idea what was wrong with them 23-Feb-20 11:36 PM Oh I've been in a room like that 23-Feb-20 11:37 PM Just not worth the trouble or time I guess 23-Feb-20 11:40 PM And I could not take any of them, because they legally could not give them out 23-Feb-20 11:40 PM I've talked to someone who does refurb, he charges 1.6k for testing and pumping 23-Feb-20 11:40 PM It's gotta be a lot more for the storage space alone 23-Feb-20 11:40 PM I just don't understand it 23-Feb-20 11:41 PM Wait, was that all the room was? 23-Feb-20 11:42 PM HPGe, Si(Li)s and Ge(Li)s (rip) 23-Feb-20 11:42 PM like 10 or 20 m², not a huge room 23-Feb-20 11:42 PM but still 23-Feb-20 11:42 PM Even so 23-Feb-20 11:42 PM Damn 23-Feb-20 11:45 PM yes 23-Feb-20 11:46 PM If you can get your hands on a pump out tool for one of the larger dewars (>30L) you are set for good times to fix so many things. But if you can’t get the annular space to hold? [salutes the dead soldier] 23-Feb-20 11:46 PM The tools are jealously guarded. 23-Feb-20 11:47 PM I've successfully DIYed two pumping adapters 23-Feb-20 11:47 PM JEALOUSLY GUARD THEM 23-Feb-20 11:47 PM they're not that hard to make tbh 23-Feb-20 11:48 PM One would think they’d be more common, and yet... 23-Feb-20 11:48 PM Something something proprietary parts? 23-Feb-20 11:49 PM https://gigabecquerel.wordpress.com/2020/01/10/canberra-hpge-repair-part-1-n/ 23-Feb-20 11:49 PM here's one 23-Feb-20 11:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200127_150611-07936.jpg 23-Feb-20 11:50 PM Hmm 23-Feb-20 11:52 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200201_201432-CD39C.jpg 23-Feb-20 11:52 PM those grooves were tge hardest part, had to make a tool for them 23-Feb-20 11:52 PM but that's it 23-Feb-20 11:52 PM the secret ingredient is loads of high vac grease 23-Feb-20 11:55 PM That’s the best part I’d imagine 23-Feb-20 11:56 PM Ohhhhhh yes. So much vac lube on those dewars. Love a good pump out. 23-Feb-20 11:56 PM that's how you recognize a well cared for detector 23-Feb-20 11:57 PM Versus robie and changer, the two lightly abused ones I know 23-Feb-20 11:59 PM I love the fact that they have names 23-Feb-20 11:59 PM but you'd think that humanizes them and causes people to want to take care 24-Feb-20 12:01 AM It does, they’re also used by students mostly (myself included) 24-Feb-20 12:04 AM oh 24-Feb-20 12:04 AM used and abused 24-Feb-20 12:06 AM Honestly the biggest issues are just files not getting saved properly or scraps of dirt from environmental samples getting knocked in. 24-Feb-20 12:06 AM Why is there such a large bismuth peak... 24-Feb-20 12:07 AM as long as the students don't have to refill ln2, worry about hv and don't touch the test port... 24-Feb-20 12:09 AM Well, they don’t do one of those things... 24-Feb-20 12:09 AM https://media.tenor.com/images/58b930b25f43202625e72493a82ebc78/tenor.gif 24-Feb-20 12:13 AM Technically I’m the only student authorized to touch the high voltage settings and there’s a specific person designated to top of nitrogen weekly so things are usually good 24-Feb-20 12:13 AM But I feel that gif a bit too much 24-Feb-20 01:16 AM that's pretty cool 24-Feb-20 01:16 AM what do you do with them? 24-Feb-20 10:08 AM They’re tied to the reactor so mostly neutron activation analysis and then environmental monitoring 24-Feb-20 10:11 AM the reactor? 24-Feb-20 10:11 AM Reed research reactor 24-Feb-20 10:14 AM nice 24-Feb-20 10:15 AM That (and school) is what takes up most of my time, there’s a bit of hobby stuff on the side though 24-Feb-20 10:21 AM if I had access to a reactor I would not need a hobby 24-Feb-20 10:23 AM There’s something to be said for the freedom to mess around with things without needing any reason to do that versus something more important though 24-Feb-20 10:24 AM but still 24-Feb-20 10:24 AM Agreed 24-Feb-20 10:24 AM It takes up a lot of my time for a reason 24-Feb-20 10:27 AM which is why I think it's sad no one does any actual work with their fusors 24-Feb-20 10:29 AM Like, they’re the only neutron source available on a hobbyist scale, right? 24-Feb-20 10:35 AM pretty much 24-Feb-20 10:35 AM most people don't even activate silver or the likes! 24-Feb-20 10:40 AM That’s all I’ve ever heard of happening 24-Feb-20 10:41 AM I have big plans for mine, but I'm not sure what goals I'll actually meet 24-Feb-20 10:41 AM like pgaa would be awesome 24-Feb-20 10:41 AM but flux rates... 24-Feb-20 11:27 AM what sort of shielding are you planning for your fusor? i am assuming the lead you have been picking up is mostly for the HPGe but now i am wondering if that is the case 24-Feb-20 11:28 AM it is mostly for the HPGe, but I also have some sheet for the x-rays 24-Feb-20 11:28 AM neutrons on the other hand will be paraffin wax and lead, maybe some borax if needed 24-Feb-20 11:29 AM ahh once i finally get to the point of thinking of shielding paraffin will not be a viable option because of the climate here 24-Feb-20 11:29 AM keep having things pop up and distracting from that project...like work and family stuff heh 24-Feb-20 11:31 AM HPDE will work even better 24-Feb-20 11:32 AM yep just more expensive but that is my planned material for moderating plus some lead 24-Feb-20 11:32 AM during the summer sometimes my garage gets pretty toasty and a mess of paraffin is not what i want to spend time on 24-Feb-20 01:38 PM I’ve been meaning to acquire lead for my HPGe. 24-Feb-20 01:38 PM I first have to fix the vacuum issue with it. 24-Feb-20 01:39 PM pumping and baking 24-Feb-20 01:39 PM and maybe some cleaning if it ever arced 24-Feb-20 01:39 PM but then you'll have a working well detector 24-Feb-20 01:39 PM and my envy 24-Feb-20 01:47 PM It works now, but it gets upset at around 2000 V. FWHM drops to an uncharacteristically awful 1.6%. (For reference, FWHM is typically a few 10ths of a percent, and this detector has +4800 V stamped on it.) 24-Feb-20 01:47 PM Before I realized what was happening, I learned that further increases kill all signal. I’m guessing this is corona discharge inside the vacuum vessel. 24-Feb-20 01:47 PM How is yours doing? 24-Feb-20 01:51 PM just refilled it 24-Feb-20 01:51 PM works perfectly at the rated voltage :3 24-Feb-20 01:51 PM btw, does yours have some kind of temp sensor? 24-Feb-20 01:53 PM Unfortunately, no. I’ve looked at the feedthroughs and schematics, and I can’t find one. 24-Feb-20 01:53 PM manufacturer? 24-Feb-20 01:53 PM 'cause I've got the pinouts for canberra 24-Feb-20 01:53 PM It seems to be a German remanufactured PGT. 24-Feb-20 01:53 PM ahh 24-Feb-20 01:53 PM well dang 24-Feb-20 01:53 PM because what you're describing might also be caused by a warm crystal 24-Feb-20 01:54 PM Interesting.... 24-Feb-20 01:54 PM can you measure current through the detector? 24-Feb-20 01:54 PM mine has an integrator output that's proportional to current 24-Feb-20 01:54 PM But it is also vacuum dependent. 24-Feb-20 01:54 PM of course, not denying that 24-Feb-20 01:55 PM I believe I have an external test point on mine. 24-Feb-20 01:55 PM that would be interesting to measure 24-Feb-20 01:55 PM if that current rises much in the fault conditions 24-Feb-20 01:56 PM I went through the procedures in the manual using the test point and everything looked good at lower voltage. 24-Feb-20 01:56 PM because it should only be the current through the crystal, not any other leakage or corona 24-Feb-20 02:00 PM That’s interesting. I don’t think I’ve tried intentionally causing the HV to get to this territory and measuring the detector current. 24-Feb-20 02:00 PM I’m looking for the manual now. 24-Feb-20 02:00 PM https://www.scribd.com/document/405055361/Gamma-and-Xray-Detectors-Rev1-200507-1-pdf 24-Feb-20 02:07 PM can't look at that link without logging it 24-Feb-20 02:07 PM It’s an IGW detector and looks like an RG 11 pre-amp. Of course it’s got a German company time stamped on the outside. (Detector Systems GMBH I think.) 24-Feb-20 02:07 PM Yeah. I hate Scribd, 24-Feb-20 02:07 PM I just don’t see it posted elsewhere. 24-Feb-20 02:08 PM it looks like the canberra equivalent of this manual 24-Feb-20 02:08 PM https://www.aps.anl.gov/files/APS-Uploads/DET/Detector-Pool/Spectroscopic-Detectors/Canberra/Germanium_Detectors_Manual.pdf 24-Feb-20 02:14 PM I’m also concerned with the valve opener. 24-Feb-20 02:14 PM I have an after-market hacked one. The trouble is that it doesn’t look like the plug can retract into the body of the opener, so it’s just loosened, and the pumping has to go though the threads. That’s great when you have a gas with pressure, but is really problematic at the molecular level. 24-Feb-20 02:16 PM ouch, yep 24-Feb-20 02:18 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_0265-0FCD1.jpg 24-Feb-20 02:18 PM That plate, at the level of the pre-amp, covers up the valve opener. There’s a groove with an O ring. 24-Feb-20 02:18 PM I could machine and weld a replacement plate with a better type of valve that would allow me to pull the original plug out, bolt on the new plug with better valve opener, and pump on that. 24-Feb-20 02:21 PM yeah I was just going to ask if you have access to a lathe 24-Feb-20 02:21 PM making those adapters isn't that hard 24-Feb-20 02:29 PM This is my HPGe’s valve. 24-Feb-20 02:29 PM oh, I misread thought you wanted to replace the pumping adapter, not the valve itself 24-Feb-20 02:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-F16D9.jpg 24-Feb-20 02:30 PM That plug only unscrews so far. It doesn’t go up into the body of the valve opener. 24-Feb-20 02:33 PM yeah that's definitely an issue 24-Feb-20 03:23 PM oof, my SiLi detector has a similar weird pump-through-the-holes kind of thing 24-Feb-20 03:23 PM i haven't managed to get it cracked open, though the vacuum's been opened on the dewar side already so i can at least fiddle with it 24-Feb-20 03:23 PM seems like an annoying machining job.. that soft brass really wants to shred up with any nonstandard turny-thingy 24-Feb-20 03:23 PM grumble grumble need to learn how to use my little lathe grumble grumble 24-Feb-20 05:27 PM Pager works perfectly, the buzz is a little noisy I think it may need a little padding but it should do the job 25-Feb-20 12:36 AM ohh in about 5 hours I will ruin my back get my lead <3 25-Feb-20 01:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_104053-D5F89.jpg 25-Feb-20 01:54 AM ordering stuff from furries... 25-Feb-20 01:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_104759-3C3CD.jpg 25-Feb-20 01:54 AM inb4 rip my back 25-Feb-20 02:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_112711-94C71.jpg 25-Feb-20 03:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_122737-DF6CA.jpg 25-Feb-20 03:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_123426-E0220.jpg 25-Feb-20 03:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_123531-39DBC.jpg 25-Feb-20 06:08 AM Nice!!! 25-Feb-20 06:10 AM now I gotta copper coat all of this 25-Feb-20 06:10 AM nah, that can wait 25-Feb-20 06:10 AM my bank account gotta recover from the lead first 25-Feb-20 06:19 AM the thin-ish top is a convincing argument for a cosmic veto 25-Feb-20 06:53 AM Why the copper coating`? 25-Feb-20 07:03 AM Where did you get the lead? 25-Feb-20 07:17 AM @rfs stopping the X-rays from the lead 25-Feb-20 07:17 AM @rdpierce a neighbour of a friend had it... was some no questions asked deal 25-Feb-20 07:19 AM Aaah 25-Feb-20 07:20 AM Yes. 25-Feb-20 07:20 AM Also shields against betas produced in the lead, e.g. pair production, Compton electron recoil, etc. 25-Feb-20 07:20 AM You typically want a graded shield from high to low Z going outside in. 25-Feb-20 07:20 AM Lead, then copper, then maybe aluminum. 25-Feb-20 07:24 AM Pb, Cu, Al, PMMA would be ideal 25-Feb-20 07:24 AM but my detector is blind to the lower energy stuff 25-Feb-20 08:18 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_171329-E0D05.jpg 25-Feb-20 08:18 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_171706-22143.jpg 25-Feb-20 08:18 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_171733-653DD.jpg 25-Feb-20 08:18 AM giant ionsation chamber thingy (?) 25-Feb-20 08:18 AM considering it came from an old paper mill and there was an empty box marked "radioactive" right next to it I'm willing to bet it was used with some Cs or Co for density, moisture or similar measurement 25-Feb-20 08:18 AM it's gonna need some good scrubbing 25-Feb-20 08:18 AM hmmm 25-Feb-20 08:18 AM it still holds pressure 25-Feb-20 08:18 AM but it rattles inside 25-Feb-20 08:18 AM considering it was for gamma there probably is some Xe inside 25-Feb-20 08:18 AM so I don't really want to open it 25-Feb-20 08:18 AM decisions to be made! 25-Feb-20 08:18 AM eh, I'll open it and refill it with Ar 25-Feb-20 09:01 AM Neat 25-Feb-20 11:58 AM well 25-Feb-20 11:58 AM that's not what I expected to find 25-Feb-20 11:58 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_205739-B6B21.jpg 25-Feb-20 12:09 PM also geez 25-Feb-20 12:09 PM I'm 11k seconds into taking a background spectrum 25-Feb-20 12:09 PM and the most prominent peak is 511 keV, at 0.05 per second 25-Feb-20 12:09 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200225_210903-DD4C3.jpg 25-Feb-20 12:09 PM closely followed by Bi214, followed by K40 25-Feb-20 02:19 PM The source from that ionization chamber? 25-Feb-20 02:19 PM lol, no 25-Feb-20 02:19 PM I didn't get that source, luckily 25-Feb-20 02:19 PM would have been one hot motherf... 25-Feb-20 02:54 PM wait, what is that spiky thing? 25-Feb-20 02:56 PM the inside of the ionisation chamber 25-Feb-20 02:56 PM oh wonky 25-Feb-20 02:56 PM i know, right? 25-Feb-20 02:56 PM never seen one like that 25-Feb-20 02:56 PM now I kind of wander what the original source was 25-Feb-20 04:08 PM Maybe you could find some residual? I mean you do have a crazy sensitive detector, there might be some daughter products or dust in there 25-Feb-20 04:16 PM presumably the 511 keV is from muons, and Bi214 would be, like.. a radon daughter? 25-Feb-20 04:16 PM and K40 is you standing too close to it? :D 25-Feb-20 04:16 PM vacuum-seal your lead castle and pump it down like an alpha spec and see if Bi214 goes away 25-Feb-20 04:18 PM Muons and K-40 probably 25-Feb-20 04:18 PM As well as from Bi214 gammas 25-Feb-20 04:18 PM Alternatively you could direct the nitrogen vent from the dewar into the castle 25-Feb-20 04:24 PM oh ya, purge gas might be simpler 25-Feb-20 04:24 PM And effectively free if you’re already cooling it 25-Feb-20 10:31 PM anyone know a super simple way to set up a pulse generator to use for calibrating the display meter on some ludlum ratemeters? 25-Feb-20 10:31 PM was thinking something like voltage divider, NPN transistor, and an arduino or something but that seems almost too simple heh 25-Feb-20 10:32 PM I got away with that once 25-Feb-20 10:32 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-FA484.jpg 25-Feb-20 10:34 PM guess i will play with it a little more, seemed like i was getting some inconsistent results from it but that could just be a bad connection 25-Feb-20 10:34 PM the type C connectors on these things are nasty 25-Feb-20 10:35 PM I can’t remember if I’ve ever seen one anywhere else 25-Feb-20 10:36 PM seems like something there would be a bunch of projects building one given all the kit geiger counters out there and surplus ludlums 25-Feb-20 10:36 PM but i was not able to find anything with a couple quick google searches (not that i looked hard) 25-Feb-20 10:36 PM What would be? 25-Feb-20 10:37 PM would be a lot of the pulse generator set ups associated with the diy geiger counter stuff 25-Feb-20 10:37 PM to make sure the displayed counts actually match up 25-Feb-20 10:37 PM Ah, yeah 25-Feb-20 10:37 PM I'd happily share the code for the little one I threw together 25-Feb-20 10:38 PM something like a DIY Ludlum model 500 25-Feb-20 10:38 PM i would be interested to see it, the setup i tried that seemed less than stellar was just using a delay and setting a pin high/low on the base of a 2n3904 i had on hand 25-Feb-20 10:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Nano_Pulser-E56D2.ino 25-Feb-20 10:40 PM It's bodged together from something else, so the commenting is less that amazing 25-Feb-20 10:41 PM not going to get any judgement on that from me 25-Feb-20 10:43 PM But other than that it's just a button and resistor and D13 is connected by a 100pF 2kV capacitor 25-Feb-20 10:45 PM interesting...somehow i had never seen decimals used in delay() only people skipping down to like delayMicroseconds() 25-Feb-20 10:45 PM will try the capacitor setup instead and see if that cuts down on the noise trouble i was having 25-Feb-20 10:46 PM Best of luck 26-Feb-20 05:56 AM oh wow 26-Feb-20 05:56 AM I have a 1g sample of Lanthanum 26-Feb-20 05:56 AM that equates to ~0.8 Bq of La-138 26-Feb-20 05:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200226_145442-1EAA6.jpg 26-Feb-20 05:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200226_145538-91DEF.jpg 26-Feb-20 05:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200226_145550-3279F.jpg 26-Feb-20 06:20 AM Arduinos may not have stable clocks 26-Feb-20 06:20 AM Some use ceramic oscillators rather than quartz crystals. 26-Feb-20 06:20 AM The DIY movement has lots of schematics for pulsers. 26-Feb-20 06:20 AM Typically, they use a quartz crystal, then a bunch of counter chips to divide the frequency down. 27-Feb-20 04:55 AM buttery smooth 27-Feb-20 07:49 AM Very nice. 27-Feb-20 09:05 AM Yaaassssss! 28-Feb-20 01:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200228_105029-CD444.jpg 28-Feb-20 03:59 AM ohhh boi 28-Feb-20 03:59 AM I just got a package from ortec 28-Feb-20 03:59 AM a manual and a "small surprise" 28-Feb-20 03:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200228_130259-96EEE.jpg 28-Feb-20 03:59 AM I'm not sure what I expected 28-Feb-20 05:11 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200228_141118-EF328.jpg 28-Feb-20 05:11 AM It's punny 28-Feb-20 05:40 AM https://twitter.com/JodyKni22638709/status/953562427446185984?s=19 28-Feb-20 05:40 AM rip 28-Feb-20 07:07 AM you mean he has now enough dust flying around to give him some cancer? 28-Feb-20 07:07 AM ah ok it's an pretty old tweet 28-Feb-20 07:07 AM oh jeez 28-Feb-20 08:16 AM Oh that’s nuts. 28-Feb-20 08:16 AM He’s got a hold of an industrial smoke detector too with a massive Am source. 28-Feb-20 08:16 AM “Great caution is called for here since I have no respirator.” And you’re dumping loose powdered radium on your desk?!?!? 28-Feb-20 08:16 AM Even better, he threatens his followers with a gun. His firearms safety skills are comparable to his rad safety. Note the finger on the trigger. 28-Feb-20 08:28 AM do you think it's a real gun? 28-Feb-20 08:28 AM the magazine looks like airsoft 28-Feb-20 08:28 AM not saying that that's any better, just asking 28-Feb-20 08:28 AM never held a real gun 28-Feb-20 08:40 AM Ah, yes that guy. When people like him get up to unsafe radioactive shenanigans, much like laser shenanigans with Spyro, friends have a habit of making sure that I don't miss them. Mainly to raise my blood pressure, I think. He really didn't appreciate the collective health physicists of twitter try to advise him against what he was doing. He sure does love his freedom. I declined the offer from someone to track down his address so I could send local hazmat to his house. 28-Feb-20 08:43 AM your friends must really like you 28-Feb-20 08:45 AM It's nice to have trained a cadre of people with enough radiation & laser safety knowledge that they can expertly spot the things I would hate. 28-Feb-20 08:54 AM I recently trained my fiancee's sister how to use her new GM for antique hunting and got to tell her all about deck markers. While going through one store, I saw something on the shelf where fiancee clearly saw my reaction and said with concern "What is it?" I then got to teach the two of them that if there was something I want to see less than a deck marker, it's components from a pre-1970's military cockpit. Especially, the compass & altimeter. Seeing as how the sister lives in an Air Force town, finding those components in antique stores and auctions it's non-zero. There's a reason no one wants to be assigned to decon project that goes anywhere near the old "Radio Shop" on a military base. You find things. Terrible things. 28-Feb-20 08:56 AM is the topic things you will hate? because have you ever heard of Galen Winsor? think i linked the video in here ages ago 28-Feb-20 08:56 AM https://www.youtube.com/watch?v=ejCQrOTE-XA&feature=youtu.be&t=4023 <- please do not eat the uranium 28-Feb-20 09:00 AM Now that is name I haven't heard in a long time. That old crank. 28-Feb-20 09:00 AM yeah scary how the nutcases have latched on to him 28-Feb-20 09:02 AM spyro! 28-Feb-20 09:02 AM Unless we want to open a new channel called #cranks_conspiracies_pseudoscience I think I'll leave it at he seems to be a focal point in the search for a Grand Unified Conspiracy Theory. 28-Feb-20 09:03 AM I happened to have a GM on me when I was in the Deutsches Technikmuseum Berlin. Lit right up when I stepped up to an aircraft control panel. 28-Feb-20 09:04 AM think this was something i also linked before that might be worth sharing again: https://www.youtube.com/watch?v=ssH9o32CZtg 28-Feb-20 09:04 AM would love to find more videos in that same vein 28-Feb-20 09:07 AM This sparks joy. 28-Feb-20 09:07 AM would the decay heat from a lump of Pu238 be enough for ignition? 28-Feb-20 09:07 AM I mean in a normal living room atmosphere 28-Feb-20 09:09 AM It depends on shape and quantity. 28-Feb-20 09:09 AM ok 28-Feb-20 09:09 AM solid grapefruit sized sphere 28-Feb-20 09:10 AM As much as the entire internet knows, I love a Good Orb. That is not the ideal configuration for Pu-238 being happy. 28-Feb-20 09:10 AM or would there be other issues with such an amount? 28-Feb-20 09:11 AM grapefruit sized sphere sounds like more than a critical mass but i do not feel like doing the math first thing in the morning 28-Feb-20 09:12 AM me neither 28-Feb-20 09:12 AM No, you don't make bombs with 238. You make RTGs. 28-Feb-20 09:12 AM MMORTGs 28-Feb-20 09:12 AM jk 28-Feb-20 09:13 AM Do that with Pu-239 and you're gonna have a bad time. You french fried when you should have pizza'd. 28-Feb-20 09:13 AM yes of course 28-Feb-20 09:16 AM Have you seen the (spoof) video about the MRE RTG ration heater? 28-Feb-20 09:16 AM https://youtu.be/9Ry4QBQejFU 28-Feb-20 09:19 AM The author Charlie Stross made ABSOLUTELY CERTAIN it crossed my eyes, because he too loves to abuse me. 28-Feb-20 09:21 AM abuse? 28-Feb-20 09:21 AM what am I reading 28-Feb-20 09:21 AM how possible would it be to build such a compact heater? 28-Feb-20 09:25 AM Easy. But making it controllable like that? Impossible. 28-Feb-20 09:26 AM how much power dissipation did those pacemaker RTG have? 28-Feb-20 09:26 AM An RTG is always on. If the heat can’t dissipate, it will build up. 28-Feb-20 09:27 AM like throwing 100s of them in a cup of noodles 28-Feb-20 09:27 AM yes 28-Feb-20 09:27 AM you know those for implants? 28-Feb-20 09:27 AM like pacemakers? 28-Feb-20 09:27 AM they are Pu238 based 28-Feb-20 09:27 AM makes me wonder why there is no revival in then IoT age 28-Feb-20 09:27 AM laurens-alcatel model 9000 ^^ 28-Feb-20 09:27 AM or Ni63 instead of Pu238 28-Feb-20 09:32 AM The other problem is the isotope. Pu-238 is an alpha emitter. You can make a Sr-90 RTG, but the shielding will produce bremsstrahlung. 28-Feb-20 09:33 AM I still want a rtg powered phone 28-Feb-20 09:33 AM Or even just a 5w usb rtg charger 28-Feb-20 09:34 AM what I mean is: Pu238 RTG were implanted in humans in the 1970-1990, right? 28-Feb-20 09:34 AM Russians loved using Sr-90 RTGs to power lighthouses. And there’s a fine Russian tradition of metal scrapping. These two things are not very compatible. 28-Feb-20 09:35 AM and an alternative is betaelectronic generation using stuff like Ni63 or tritium 28-Feb-20 09:36 AM Tritium only gets you a few microwatts 28-Feb-20 09:36 AM @Treehouseman yeah a small powerbank 28-Feb-20 09:36 AM What am I going to do with that 28-Feb-20 09:37 AM with microwatts? nothing much 28-Feb-20 09:37 AM making ants a tea? 28-Feb-20 09:37 AM Plus tritium only has a 10 year half life 28-Feb-20 09:38 AM yeah Pu238 is better 28-Feb-20 09:38 AM We need alphavoltaics and just shove it full of radium :D 28-Feb-20 09:38 AM ehehe 28-Feb-20 09:39 AM Oh, this is sad. Three hunters in the woods in Georgia found an abandoned Sr-90 RTG and huddled around it for warmth. That didn’t end well for them.... 28-Feb-20 09:39 AM https://bellona.org/news/nuclear-issues/radioactive-waste-and-spent-nuclear-fuel/2003-11-two-strontium-powered-lighthouses-vandalised-on-the-kola-peninsula 28-Feb-20 09:50 AM ohhh 28-Feb-20 10:01 AM @rdpierce https://www.youtube.com/watch?v=BE5T0GkoKG8 28-Feb-20 10:01 AM The IAEA report on that operation is also quite the read. 28-Feb-20 10:02 AM and look 28-Feb-20 10:02 AM some scary pics in there 28-Feb-20 10:02 AM 'tho they still remind me of my moms lasagna... 28-Feb-20 10:08 AM An old favorite story of the Source Recovery Program. 28-Feb-20 10:13 AM The mobile hot cell shown here is neat https://www.youtube.com/watch?v=ngq_6AzP738 28-Feb-20 12:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200228_213655-B1F2A.jpg 28-Feb-20 12:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200228_214913-B1FBF.jpg 28-Feb-20 12:49 PM I want ultra low background cups! 28-Feb-20 01:42 PM does maestro have an automatic/lazy isotope peak lookup thingy? 28-Feb-20 01:42 PM curious 28-Feb-20 01:42 PM also, have you tried a new background count with those LEDs in there? 28-Feb-20 01:42 PM yes to both 28-Feb-20 01:42 PM can't see the LEDs with the detector 28-Feb-20 01:42 PM also maestro can use libraries, but the preinstalled aren't that great 28-Feb-20 01:42 PM it displays where your peak is, what it thinks it is and how certain it is 28-Feb-20 02:13 PM Any thoughts on gamma spec software? 28-Feb-20 02:13 PM Has anyone used FitzPeaks? 28-Feb-20 02:17 PM I should try it 28-Feb-20 02:17 PM can you feed it with maestro? 28-Feb-20 02:17 PM dang it 28-Feb-20 02:17 PM it's 16 Bit 28-Feb-20 02:17 PM won't work at all on my pc 28-Feb-20 02:32 PM "IMMA TAKE A SPECTRA OF [looks around office] $ITEM!!!" is a universal behavior when playing with any new spec set up. 28-Feb-20 02:35 PM guilty as charged 28-Feb-20 02:40 PM Also applies to RF spectrum analyzers 28-Feb-20 02:42 PM optical too >_> 28-Feb-20 02:42 PM honestly, every kind of analysis tool 28-Feb-20 02:43 PM long exhale dude, there's, like, rainbows.. in everything.. everywhere.. cough cough 28-Feb-20 02:43 PM that's pretty gay 28-Feb-20 02:44 PM you know it ✨ ️ 28-Feb-20 02:45 PM High energy ionizing rainbows 28-Feb-20 03:04 PM I've been trying to find a good analysis tool 28-Feb-20 03:04 PM I'm looking for something with a good library that will auto identify peaks 28-Feb-20 03:04 PM So far, I've got access to simple tools that can control MCA, facilitate basic calibration and background selection, and measure FWHM 28-Feb-20 03:06 PM maestro kind of does that 28-Feb-20 03:07 PM Interspec can, but it’s just for analysis once you have a spectrum 28-Feb-20 03:07 PM I have a SpecTech UCS-20 and I'm avoiding that because it has no 64 bit drivers 28-Feb-20 03:07 PM I'm now going EPICS and Mark Rivers' IDL tool 28-Feb-20 03:07 PM It just has x-ray libraries 28-Feb-20 03:08 PM maybe you can import some libraries? 28-Feb-20 03:08 PM And I don't think it will auto ID peaks 28-Feb-20 03:08 PM I don't mind two separate tools 28-Feb-20 03:08 PM The EPICS / IDL outputs its spectra data in a self describing file format so I could convert it into some other format. 28-Feb-20 03:48 PM "IMMA TAKE A SPECTRA OF [looks around office] $ITEM!!!" is a universal behavior when playing with any new spec set up. @funranium Can confirm. Pretty sure my coffee maker has cancer after pXRF all the things. Never know what you'll find. 28-Feb-20 03:48 PM @rdpierce I compiled a list at some point just doing background research on what's out there: * [https://www.jimfitz.co.uk/fitzpeak.htm FitzPeaks Gamma Analysis and Calibration Software] You will need KB917607 for windows help files to work under modern operations systems (Windows 7 64-bit) * [https://www.effemm2.de/spectragryph/ Spectragryf] * [http://www.spectrumtechniques.com/software/USX_USB%20x32%201_1_07a.exe Spectrum Techniques UCS20 Software] * Canberra Genie 2000 [https://www.kb.sit.auckland.ac.nz/2013/10/25/department-of-physics/ Not Free. Requires a hardware key that is likely sentinel-based] * [https://arxiv.org/pdf/1511.04362.pdf Other software per paper: "Evaluation of Peak-Fitting Software for Gamma Spectrum Analysis"] GammaVision * Ortec / Does not seem to be free [http://www.iki.kfki.hu/nuclear/hypc/index_en.shtml HypermetPC] * Free VISPECT SAANI Supposedly open-source but seems to be unobtanium. Might want to contact them. Looks like this is a rewrite of Vispect IDeFix WinDIMEN 28-Feb-20 03:48 PM err, that didn't go well. Didn't expect it to expand all the URLs.... Sry. 28-Feb-20 03:53 PM that's alright, actually could you cc all that into #resources too? >.> these looks quite useful 28-Feb-20 03:54 PM Honestly, I feel like a wiki is the proper format for this. But, sure... I will paste. 28-Feb-20 03:55 PM i think we were considering shoring up a wiki at some point, dunno if anything came of that 28-Feb-20 03:55 PM @rdpierce There is one that in particular does the auto-ID, but hell if I can remember what it was. 28-Feb-20 03:55 PM I've used a weird combination of XRF spectra -> EMSA-format -> NIST-DTSA. This is somewhat cursed, but highly effective, if one cares about XRF... 28-Feb-20 03:55 PM Oh, right, so @rdpierce , since Spectragryph does gamma, if you get your stuff to conform to EMSA format, it'll do pretty gamma auto-ident things. 28-Feb-20 03:55 PM But IIRC, there was another one that was more "mainsteam?" and did the auto-ident. 28-Feb-20 03:55 PM Def look at this paper: https://arxiv.org/pdf/1511.04362.pdf 28-Feb-20 03:55 PM I have things in my brain that I would gladly contribute if there were a wiki. I don't do too well with Chat/forums. Makes me crazy. 29-Feb-20 04:42 AM https://www.youtube.com/watch?v=iPI0Xx77snA Oh geez, after mister snorting-deckmarker-paint there's now this guy 29-Feb-20 06:28 AM nice 29-Feb-20 06:28 AM but y 29-Feb-20 06:28 AM the dirty fingernails 29-Feb-20 06:28 AM :3 29-Feb-20 09:01 AM so much...why? 29-Feb-20 09:06 AM I’m guessing he wants to make an AmBe neutron source? 29-Feb-20 09:08 AM why would you even try removing the source plate from the button for that? not going to get much activity out of those little buttons especially with them all scraped/twisted up... 29-Feb-20 09:08 AM If so, given his complete disregard for safety, I think Be dust exposure will kill him long before Am-241 contamination.... 29-Feb-20 09:08 AM not sure this guy would even know that is possible from the comments too... 29-Feb-20 09:08 AM i wonder how much of the Am241 ended up on that table from the scraping with that spike 29-Feb-20 09:20 AM I’m looking for the opposite - a very low activity electrodeposited Am-241 source. Looking for something preferably in the 10-100 Bq range for energy calibration of an alpha spectrometer. A smoke detector foil sample is going to be way too active, and I thought I saw somewhere that smoke detector foils may have something else electrodeposited on top, which will scatter the alphas and smear the peaks down. 29-Feb-20 09:22 AM does it have to be Am241? you could get one of those antistatic brushes with Po210 that have a bit lower activity (if i am remembering right anyway) 29-Feb-20 09:25 AM That’s a good energy for calibration, but there are some concerns. 29-Feb-20 09:25 AM Anything that can ionize enough air to act as an anti-static source will be screaming hot. 29-Feb-20 09:26 AM ahh, alpha spectroscopy is not something i have looked into much yet 29-Feb-20 09:26 AM was not really considering that aspect of samples 29-Feb-20 09:27 AM And the deposition process may be problematic too. For alpha spec, you really want a 1 atom thick coating. Anything more than that and you get self-shielding / scattering. 29-Feb-20 09:27 AM Which smears the peaks downward. 29-Feb-20 09:27 AM Also the 138 day half live means I have to regularly replace the calibration source. 29-Feb-20 09:30 AM makes sense, did not realize alpha spec was usually done on such low activity samples 29-Feb-20 09:30 AM what are you planning to use it for? 29-Feb-20 09:36 AM I have some sample disks that someone else prepared. 29-Feb-20 09:36 AM Eventually I’d like to be able to learn the process to produce my own samples. 29-Feb-20 09:36 AM Things like extracting radon daughters from tobacco. 29-Feb-20 09:36 AM Or looking for trace contamination in soil samples. 29-Feb-20 09:36 AM The nice thing about alpha spec is that backgrounds are so incredibly low (typical detectors are advertised as 30 counts per day) that level of detection is low. 29-Feb-20 09:36 AM Doing quantitative work isn’t really possible at an amateur level because you need to spike a sample with an unobtainium tracer. 29-Feb-20 09:36 AM E.g. if you want to quantify Pu, then you spike the sample with a known activity of Pu-242 which is pretty much non-existent even in nuclear reactor debris. 29-Feb-20 09:44 AM the sample prep seems like it might be challenging in a hobby setting but sounds like a cool project 29-Feb-20 09:44 AM Then by counting the Pu-242 peak, you can compute your extraction and detector efficiency. 29-Feb-20 09:44 AM Then you can use that to correct the activity of the Pu-239/240 peak, and knowing the sample mass, arrive at Bq/kg. 29-Feb-20 09:44 AM Of course you need an NRC license to buy Pu-242 and it isn’t cheap.... 29-Feb-20 09:44 AM I’m hearing conflicting things about how easy it is to do at an amateur level. 29-Feb-20 09:44 AM The electrodeposition itself doesn’t look hard at all, except it means shelling out for a platinum electrode wire. 29-Feb-20 09:44 AM Getting a sample into solution, and separations via ion exchange resin, look a bit more complicated. Sample digestion typically requires a strong acid. 29-Feb-20 09:44 AM I’ve also seen perchloric acid listed as part of many processes. That really gave me pause, as I know that stuff can crystalize into explosive salts in fume hood ductwork. They make special fume hoods specifically for perchloric acid. 29-Feb-20 09:44 AM However, I’ve also heard that only weak perchloric acid is needed for these processes, and that is safe in normal fume hoods. 29-Feb-20 09:44 AM My chemistry knowledge is not presently where it needs to be to attempt any of this. I’m wondering if anyone else here has experience. 29-Feb-20 09:59 AM i only know enough to know that i do not know enough to even consider that sort of thing, especially not without a proper lab set up 29-Feb-20 03:25 PM https://twitter.com/szeloof/status/1233649648126038016 29-Feb-20 07:19 PM https://twitter.com/vpikhur/status/1218938855975342081 29-Feb-20 07:19 PM humble brag 29-Feb-20 07:28 PM As a reminder, if you buy yourself a “desktop XRD” on eBay know the rules for your local jurisdiction. You may have a registration and licensure requirement for it. 29-Feb-20 07:29 PM We had to go through state registration and training requirements for the pXRF. 29-Feb-20 07:33 PM I think that also includes SEM 01-Mar-20 01:52 AM what? 01-Mar-20 01:52 AM I print the permissions by myself 01-Mar-20 01:52 AM and now I want again a faxitron 01-Mar-20 03:07 AM don't get arrested 01-Mar-20 03:07 AM (also do note Adam's latest addition to the server rules) 01-Mar-20 03:07 AM still think the US NRC deserves an ARRL-style hobbyist licensing association 01-Mar-20 04:06 AM arrl sucks 01-Mar-20 04:19 AM what I mean is: I'm not a fan of license fckery 01-Mar-20 04:19 AM my primarily field of interest is atomic 01-Mar-20 04:19 AM not hobby bureaucracy 01-Mar-20 09:16 AM If there is one topic on this server that has the possibility get you significant fines, possible jail time, and the media will make a pariah of you if you play cowboy, it’s this one. The field does not need more fuel for public fear of radiation thanks to cavalier messing around. It already has plenty from the Whole Foods bulletin boards. 01-Mar-20 09:16 AM The rules and regs for lasers around the world are rather fast and loose. They most definitely are not for ionizing radiation. 01-Mar-20 09:26 AM which topic? 01-Mar-20 09:26 AM using benchtop xray sources or electron microscopes? 01-Mar-20 09:26 AM twf 01-Mar-20 09:26 AM if this server is not the right one for free speech about such topics 01-Mar-20 09:26 AM what would be the right one? 01-Mar-20 09:26 AM and what's the purpose for this one? 01-Mar-20 09:26 AM talking about hobby bureaucracy and license btchery? 01-Mar-20 09:26 AM pls 01-Mar-20 09:26 AM @funranium you're joking? 01-Mar-20 09:32 AM I assure you he isn’t 01-Mar-20 09:33 AM makes it even more funny 01-Mar-20 09:33 AM how about a subchannel named #hobby-bureaucracy ? 01-Mar-20 09:35 AM The topic of #radiation as a whole. Do it right, or not at all. 01-Mar-20 09:36 AM oh, you think most of the people in here have done all their official paperwork for what they're trying todo? 01-Mar-20 09:36 AM I mean someone is talking about having faxitrons or similar bench top xray devices 01-Mar-20 09:36 AM and all you're thinking about is "make your paperwork"? 01-Mar-20 09:36 AM tfw 01-Mar-20 09:36 AM c'mon 01-Mar-20 09:41 AM Radiation safety is my profession. Under the Health Physics Society professional code of ethics, I am required to advise you of your responsibilities to yourself and others with your "hobby". You have been duly warned. 01-Mar-20 09:42 AM aw jeez 01-Mar-20 09:42 AM I guess it's always the same 'professionalisation' of 'science' forums :3 01-Mar-20 09:42 AM nvm 01-Mar-20 09:44 AM This was your opportunity to learn something today. I am sorry you didn't like what you learned. 01-Mar-20 09:44 AM whaat? 01-Mar-20 09:44 AM learned what? 01-Mar-20 09:44 AM what your opinion is? 01-Mar-20 09:44 AM it's the same with lasers 01-Mar-20 09:44 AM I want to talk about the physics 01-Mar-20 09:44 AM you're talking about the safety 01-Mar-20 09:44 AM it's okay - I can handle that 01-Mar-20 09:46 AM So what sort of licensing is required to own/operate one of those desktop xray units? 01-Mar-20 09:47 AM but .... in this case it was simply 'a faxitron is an awesome device' 01-Mar-20 09:47 AM Do you need licensing to run a tube amp too...? 01-Mar-20 09:47 AM @LRM ask the professional 01-Mar-20 09:50 AM <𝓕ermion#6024> I’m getting increasingly angry over the non seriousness. 01-Mar-20 09:51 AM @LRM Depending on the amount of incidental radiation you are generating, you may. If you are generating fields that would qualify as a Radiation Area (AKA 5mR/hr), under the NRC regs you have an obligation to post that just to warn people what going on in the area they are walking into. For the the desktop x-ray units and very interesting amps, it matters which state you are in. In CA, MA, TX, NM, NY, FL for a quick list, you have to register the unit with the controlling agency, usually the Dept. of Public Health or whatever it is called locally. 01-Mar-20 09:52 AM Wow...almost all of the tube amps I have ever seen people use will make a gieger counter scream across the room 01-Mar-20 09:52 AM Registration of radiation producing machines is different than licensure for radioactive materials. 01-Mar-20 09:53 AM <𝓕ermion#6024> I use a tiny cobalt 60 source and that requires markings on all the doors. 01-Mar-20 09:53 AM <𝓕ermion#6024> This stuff is quite serious 01-Mar-20 09:54 AM This is one reason why RPMs are tricky, because not every state agrees on the same definitions for what requires registration and what they may want beyond that. But the NRC has the overarching control of radiation exposure with the basic hazcom of "Do you have a field people should know about? TELL THEM." 01-Mar-20 09:55 AM as if there is no difference between a faxitron and a Co60 source 01-Mar-20 09:55 AM jeez 01-Mar-20 09:56 AM It's quite significant. Radiation type and energy matter for absorbed dose calculation. 01-Mar-20 09:56 AM <𝓕ermion#6024> Not the point I was making... 01-Mar-20 09:56 AM it's pretty annoying if every nice topic triggers you 'safety instructors' 01-Mar-20 09:56 AM srsly 01-Mar-20 09:56 AM it's lame 01-Mar-20 10:01 AM Seems like the California laws on this subject are a lot to read...and mostly deal with medical sources/uses. Have not yet found the part of the law dealing with industrial use sources besides an exemption for bomb squads... 01-Mar-20 10:08 AM They're tangled, that's for sure. :) Always best to start at the "Definitions" section in any regulation you read just to find out how they're using language here. You can end up finding a lot of variation between county, state, and feds on pretty much any topic. The quick summary for registration in CA can be found here: https://www.cdph.ca.gov/CDPH%20Document%20Library/ControlledForms/rh2261cInstructions.pdf Depending on what your tubes are for, you may escape registration. I was asked to register an ion implanter as an accelerator due to the field it generated but then the klystron in the adjacent room with a similar field was not, but posting was required no matter what. 01-Mar-20 10:13 AM Radiation producing tube amps sound like absolute beasts 01-Mar-20 10:13 AM like +10kW things 01-Mar-20 10:14 AM Their incidental radiation production tends to be all fairly low energy x-ray but, hoo nelly, do they make a lot of it. All about that amperage. 01-Mar-20 10:15 AM At what B+ and what type of tubes? 01-Mar-20 10:15 AM Or antique stuff with tube rectifiers instead of silicon? 01-Mar-20 10:15 AM Even 10kW from a 4CX5000A requires only around 7500volts B+ 01-Mar-20 10:17 AM The old power rectifiers, definitely. We had some circa-1950s sets that had to be kept in their own room when operating due to the >.5Gy/hr field they were generating. 01-Mar-20 10:17 AM wew 01-Mar-20 10:17 AM the worst offenders i have seen are only about 300W-500W units 01-Mar-20 10:17 AM and yeah generally 60s/70s designs 01-Mar-20 10:17 AM Again, all soft x-ray. The jump to silicon makes those x-rays soft enough that they're generally self-absorbed in the glass of the tube. 01-Mar-20 10:17 AM I was aware of folks using old DY86 and 2C2C rectifiers to generate X-rays when run coldcathode and the old TV HV rectifier tubes having problems wiht x-ray emissions 01-Mar-20 10:21 AM The old TV rectifiers had emission issues, but that was the what lead to: 1) The FDA getting a new product safety charter after the Christmas TV Nightmare. 2) TV box design changing to make sure that you were kept at a safety distance from that emission if you were standing next to it at a cocktail party. 3) Some lead going into the glass of the TV tube. 01-Mar-20 11:20 AM @LRM if I can translate this one for you, it says "If your incidental production exceeds 5mR/hr at 30cm, you need to register this." Again, strictly CA rule. https://govt.westlaw.com/calregs/Document/I83F66730986411E0A007F902004D9A59?viewType=FullText&originationContext=documenttoc&transitionType=CategoryPageItem&contextData=(sc.Default) 01-Mar-20 11:20 AM @LRM Sigh, I just remembered Westlaw regularly breaks links. Here's the exemption text. The following devices and materials do not require registration: (a) Electrical equipment that produces radiation incidental to its operation for other purposes, but which does not produce radiation in any area accessible to individuals such that there is a reasonable likelihood that any individual will receive a radiation dose to the whole body, head and trunk, gonads, or lens of the eye or active blood-forming organs in excess of 0.5 rem in a year. (b) All radioactive materials except as specified in sections 30192.1 and 30192.6. 01-Mar-20 11:22 AM Yeah, I saw that one. I have no dose rate reference just something I noticed when repairing the amps for someone. Thanks for the link though 01-Mar-20 11:22 AM Was more idle curiosity than anything 01-Mar-20 11:24 AM It's one of those coded-language things that gets exasperating. If they say they're concerned about whole body doses, they're looking at dose rates at a distance of 30cm. If they say extremity, they mean 5cm. If they say contact, that's self-explanatory. 01-Mar-20 11:24 AM And then shipping is interested in 1m and 2m gamma dose rates, but that's DOT stuff. That's a whooooooole other realm of fun. 01-Mar-20 08:07 PM Has anyone seen emissions like that from SEMs? 01-Mar-20 08:07 PM One SEM I've worked with has radiation warnings inside the chamber; essentially, that certain shields need to be in place that cover up thinner blank plates for non-installed detectors. 01-Mar-20 08:25 PM SEM or TEM? 01-Mar-20 08:25 PM SEMs don't go more than 40kV AFAIK 01-Mar-20 08:25 PM TEMs on the other hand go to 125kV 01-Mar-20 08:27 PM I’ve never seen an SEMs present a problem other than the time someone decided to replace the target stage window with optical quartz, which is a waveguide. Other than that, they’re inherently self-shielding. TEMs can go up to 400kV, though they tend to have current so low you don’t see anything. Leave those port guards in place though. 01-Mar-20 08:34 PM But, my goodness, if you start pulling those port covers? 50mR/hr at 30cm from that port. 01-Mar-20 08:55 PM Thanks. This SEM tops out at 30 kV. 01-Mar-20 08:55 PM Given the chamber thickness, it seemed like it should be self-shielding, assuming, obviously, that the port guards are in place. 01-Mar-20 09:10 PM but how do you get vacuum without them? 01-Mar-20 09:11 PM In that particular column, there were [shakes head sadly] optical quartz windows for shooting lasers in. 01-Mar-20 09:11 PM Behind those ports covers, that is. 01-Mar-20 09:15 PM It's simply a bidirectional port, laser goes in, xrays go out :D 01-Mar-20 09:15 PM aaaah 01-Mar-20 09:15 PM ...yes. Yes it is. 02-Mar-20 01:08 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-2CEB5.png 02-Mar-20 01:10 PM I WANT thAt SIGN SO BAD 02-Mar-20 03:34 PM Did some digging and the tags in a since-deleted tumblr post indicate the picture was taken in seattle? 02-Mar-20 04:53 PM Should have them available from NuclearKatie soon. 02-Mar-20 05:45 PM Put it over the litter box? 03-Mar-20 04:33 PM As I recall, a while back, I was being cranky about the Mini-Monitor Series 900 GM and expressing a sincere desire to flush all of them down the toilet. I recall someone said that if I was going to just throw one away, they’d happily take it. While I consider it cruel to inflict these meters on someone else, I do have one that’s up for grabs. Who was it that wanted it? 03-Mar-20 04:35 PM I’d happily take it if you can’t track them down 03-Mar-20 04:49 PM This is a pig in a poke meter, formerly from the Salk Institute. It is very much not calibrated anymore, not that these are are particularly accurate at the best of times. Did I mention that I hate these meters? Because I do. 03-Mar-20 04:50 PM what's so bad about them? 03-Mar-20 04:50 PM lowers the blast shields 03-Mar-20 04:53 PM There’s a lot of things. The most important one is that they are a pain to calibrate, which involves cracking them open and using roach clips to hook them up to pulser, and the chance to get shocked while doing so. And once you achieve that calibration, if you look at the meter funny it will lose it. 03-Mar-20 04:54 PM oh that cable's not detachable huh 03-Mar-20 05:01 PM is definitely good for random GM meters, in any event 03-Mar-20 05:07 PM In terms of people doing research, if you told me you used a Mini-Monitor to generate your numbers, I would promptly throw your paper in the garbage. 03-Mar-20 05:07 PM It is functional for contamination control. 03-Mar-20 05:14 PM That’s an impressively annoying sounding meter. Why didn’t they use a connector on the darn cable though. 03-Mar-20 05:14 PM Just for equipment longevity 03-Mar-20 05:14 PM Or was that the goal... 03-Mar-20 05:18 PM Because British malaise 1970 design. And it NEVER changed. It is the exact same meter. 03-Mar-20 05:18 PM If there was ever a topic that made me want to use all the swear words the bot won’t let me... 03-Mar-20 05:20 PM Somehow interfacing one of these meters with that cubiio laser engraver thing 03-Mar-20 05:20 PM explodes with all the swearing I can’t do 03-Mar-20 05:24 PM Sorry about that 04-Mar-20 12:02 AM @funranium it was me, I'll still gladly take it! 04-Mar-20 08:07 AM @GigaSquirrel it has already shipped. :( Fear not, the next of these cursed meters to come into my hands is yours. 04-Mar-20 08:08 AM yay! 04-Mar-20 08:09 AM Because if they lay around here they might turn into spare parts to try to keep another one of these hellspawn alive. 04-Mar-20 08:09 AM XD 04-Mar-20 08:11 AM And, sadly, there is always another. Maybe not today, maybe not tomorrow, but it is an inevitability. 04-Mar-20 08:12 AM oh no 04-Mar-20 08:12 AM :P 04-Mar-20 10:55 AM yay! 04-Mar-20 10:55 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B0AC1.png 04-Mar-20 11:02 AM Those were dimes they pounded with neutrons until they were somewhat active right? 04-Mar-20 11:04 AM Yep! 04-Mar-20 11:06 AM awww, it was an extremely short lived isotope it made, so really it's just a visual souvenir and not an active one 04-Mar-20 11:06 AM yeah for sure 04-Mar-20 11:06 AM Though I'm sure you could fix that with your dime :P 04-Mar-20 11:06 AM you know, for testing 04-Mar-20 11:07 AM I'm not 100% sure 04-Mar-20 11:07 AM wouldn't that count as cheating? 04-Mar-20 11:07 AM congrats! 04-Mar-20 11:07 AM it's an altered historical piece 04-Mar-20 11:07 AM speaking of which...that oak ridge 50th anniversary coin i posted a photo of is in the mail to me at the moment 04-Mar-20 11:07 AM I'd rather irradiate some modern stuff 04-Mar-20 11:07 AM would it still be altered after a few minutes/hours? 04-Mar-20 11:08 AM it will be altered forever, you've changed the isotopic composition! 04-Mar-20 11:14 AM interesting never realized it was a Sb-Be neutron source they were using...not a pairing i remember hearing about before 04-Mar-20 11:14 AM huh? I thought it was PuBe 04-Mar-20 11:14 AM Because SbBe will be Gamma Be 04-Mar-20 11:14 AM evil high energy gamma 04-Mar-20 11:14 AM 1.7 MeV gammas giving 23 keV neutrons 04-Mar-20 11:15 AM https://www.orau.org/ptp/collection/medalsmementoes/dimes.htm 04-Mar-20 11:15 AM with 210000 n/s for 10^10 Bq 04-Mar-20 11:15 AM oh wow 04-Mar-20 11:15 AM toasty 04-Mar-20 11:16 AM "The irradiator works as follows: A mixture of radioactive antimony and beryllium is enclosed in a lead container. Gamma rays from the antimony are absorbed by the beryllium atoms and a neutron is expelled by the beryllium atom in the process." 04-Mar-20 11:16 AM ooooh "At some point, the antimony-beryllium source was replaced by a plutonium-beryllium source in which the alpha particles emitted by Pu-239 were absorbed by beryllium-9. " 04-Mar-20 11:18 AM at this point in time it must have been replaced because the museum workers got like acute radiation sickness 04-Mar-20 11:18 AM after all it was the 60s 04-Mar-20 11:19 AM might just be they got tired of having to reactivate the antimony? if we are trying to find the least pessimistic possibility anyway 04-Mar-20 11:19 AM ive actually been to that museum and i don't think they have enough employees for anyone to get irradiated but maybe things were different in the 60s 04-Mar-20 11:19 AM i saw a whole two people when i was checking it out, the person working the gift shop and the janitor 04-Mar-20 11:24 AM geez 04-Mar-20 11:24 AM I'd love to go there 04-Mar-20 11:28 AM only reason ive been is i begged my parents to make an hour detour to Oak Ridge on a family vacation as a kid heh 04-Mar-20 11:28 AM well, young teenager anyway 04-Mar-20 11:30 AM oak ridge and los alamos are two of the places I have to visit 04-Mar-20 11:30 AM or work at 04-Mar-20 11:30 AM we'll see where life takes me 04-Mar-20 11:31 AM both would be super interesting 04-Mar-20 11:33 AM yep 04-Mar-20 11:33 AM I have some detectors from oak ridge tho 04-Mar-20 11:34 AM same haha 04-Mar-20 11:34 AM got my friend who lives near there on the lookout for cool Oak Ridge stuff too 04-Mar-20 11:34 AM so far he has only found a couple of the 50th anniversary coins 04-Mar-20 11:34 AM do your detectors have any info on where they were used? one of mine is from SS Office, one is from EG-21 Fire Station, and the one with the SNM sticker is from G-219 04-Mar-20 11:34 AM not a whole ton of info out there about the old building names used in Oak Ridge unfortunately 04-Mar-20 11:34 AM https://www.orau.org/ptp/articlesstories/radwarnsymbstory.htm <- interesting description of the development of the radiation trefoil 04-Mar-20 11:42 AM Another factor in its favor was its cost. . . The high cost will deter others from using this color promiscuously. lol 04-Mar-20 11:42 AM i love that the trefoil is a precisely-specified design because it has always subtly gotten under my skin when i see one in media that's completely wrong 04-Mar-20 11:42 AM (also because i spent all of grade school carving them into my composition notebooks and always wanted them Just Right, natch) 04-Mar-20 11:47 AM another interesting description of the origins of radiation related terminology: https://www.orau.org/ptp/articlesstories/names.htm 04-Mar-20 11:47 AM did not realize they had so many neat articles on there...have only really seen the topical stuff like the dimes or detectors and radioactive things 04-Mar-20 11:55 AM @qualia hah I also scribbled them here and there at that age. 04-Mar-20 11:58 AM dang this is like what happens when you get reading something on wikipedia and click the links 04-Mar-20 11:58 AM https://www.orau.org/ptp/Library/mddc-997.pdf very neat paper about one of the first handheld portable survey meters developed for use in the nuclear program 04-Mar-20 11:58 AM "Cutie Pie" 04-Mar-20 11:58 AM haha 04-Mar-20 01:37 PM The Cutie Pie lives on in the hearts and on top of the filing cabinets of old health physicists. Did it work great? Not really. Did you need to hold it out like a gun and point it at the source? Nope, but the shape and holster encouraged that kind of behavior. 04-Mar-20 05:21 PM I gave a talk at Oak Ridge about EPICS and beer brewing. The EPICS conference was a lot of fun. We got a tour of the Spallation Neutron Source. 04-Mar-20 05:21 PM Of course they were very explicit about driving directions, as in turn on this road, NOT THAT ROAD unless you really like looking at the business end of an AR-15.... 07-Mar-20 01:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200307_104401-980AD.jpg 07-Mar-20 01:45 AM Yay new friends! 07-Mar-20 02:01 AM The Gd is mostly for playing around 07-Mar-20 02:01 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200307_105358-9AECE.jpg 07-Mar-20 02:01 AM this will be the final mix 07-Mar-20 07:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8762A.png 07-Mar-20 07:28 AM They actually all contain what they should 07-Mar-20 09:22 AM what are you planning to use those for besides super clean spectrum envy? 07-Mar-20 09:29 AM heh...guess asking an eBay seller you are pretty sure should not be selling one of those Faxitron MX-20 units what licensing/reporting requirements there are for owning/operating one just ends with them removing the item from eBay all together " This listing was ended by the seller because the item was lost or broken" 07-Mar-20 09:29 AM would think someone who seems to specialize in medical imaging equip would know better 07-Mar-20 09:41 AM took a few mins to check out inside of those Ludlum model 12 units i grabbed and https://pbs.twimg.com/media/EShh9ceUEAEH8ls?format=jpg&name=4096x4096 07-Mar-20 09:41 AM do not think capacitors are happy when they look like that 07-Mar-20 09:46 AM the caps absolutely do not care if they look like this :D 07-Mar-20 09:46 AM I'm going to use them for efficiency calibration 07-Mar-20 09:58 AM Well done @LRM. You did a safety. 07-Mar-20 10:03 AM @GigaSquirrel my main concern isnt the cracked coating but the mystery corrosion at the right leg. no idea what that could be but it seems associated with the capacitor somehow 07-Mar-20 10:05 AM Are you having issues with the unit or is this just about precautions? 07-Mar-20 10:06 AM yeah this unit does not work properly at all, the tag says "threshold too high" but i have not dug into it beyond taking a quick glance at the boards 07-Mar-20 10:10 AM Hmm, older configuration on that Ludlum. Probably a 1980s model with five digit serial number. If you identify your broken components, I may have bits in the meter boneyard. 07-Mar-20 10:14 AM 4 digit serial numbers on them...think these are late 70s vintage. not too worried about getting them working but i might take you up on that offer if i get stuck. the one i wanted to be working is fine after some cleaning (with the SNM sticker) but the other two will be more involved. 07-Mar-20 10:14 AM Oh dang, nice score. 07-Mar-20 10:16 AM the SNM unit has a 5000 range serial, one is in the 8000s, and the one in the photo is 9029 07-Mar-20 10:16 AM https://i.gyazo.com/90c39551b39406c7ee798e8ddb7f9726.jpg 07-Mar-20 10:16 AM do not think ceramic caps have anything to cause that kind of corrosion in them soooo how odd that is. 07-Mar-20 10:16 AM battery compartment looks good so it shouldnt be battery related 07-Mar-20 10:19 AM Huh. That's not great. 07-Mar-20 12:01 PM <𝓕ermion#6024> There may have been flux left on the board 07-Mar-20 12:01 PM <𝓕ermion#6024> And then the dust sticks to the flux over time. 07-Mar-20 12:01 PM <𝓕ermion#6024> Just a guess tho. 07-Mar-20 12:01 PM <𝓕ermion#6024> And those cracks look like they’re just in the wire encapsulation. 07-Mar-20 12:01 PM <𝓕ermion#6024> Could lift a leg and use an lcr meter but I would guess it’s not the problem. 07-Mar-20 02:46 PM https://www.youtube.com/watch?v=fwl1JNoFdhg 07-Mar-20 02:46 PM oh god why 07-Mar-20 02:51 PM 30 seconds in and i am questioning if i want to watch more 07-Mar-20 02:52 PM it only gets worse 07-Mar-20 02:56 PM wonder if any will mention this to their doctors when they inevitably get ill from that amount of exposure 07-Mar-20 02:56 PM they're russian, put it down to heavy drinking 08-Mar-20 05:52 AM my god.... 08-Mar-20 05:52 AM reeeeeeeeeeeeee 08-Mar-20 05:52 AM and then his foot is all 'itchy' apparently 08-Mar-20 09:31 AM I made it a few minutes in and felt I had seen enough. It reminded me that back in my urban exploring days, the discovery of an abandoned x-ray unit in the old military hospital prompted a call to the state, lest someone else decide to liberate it. 08-Mar-20 09:38 AM oh nice 08-Mar-20 11:26 AM Should I start a task force for the liberation of captive xray units? :P 08-Mar-20 04:01 PM Well he's now sterile 08-Mar-20 05:42 PM Yeah, this latest Kreosan video is exceeding crazy level of known Russian fellow Sifun, how managed to get X-ray & microwave burn in 1 week, and ended up in hospital (he was also making an X-Ray video of his hand, but his HV source was weaker). Guys at the end of the video are saying that they feel that exposed hands and feet are "burning". So, definitely got some serious doze. And as voltage was quite high, it's not just skin. Their last teased X-Ray tube with rotating anode could be lethal... 08-Mar-20 05:42 PM And they say several times that radiation is emitted like a beam, but it is not - it's in all direction, only somewhat attenuated by the tube case, which is less of an obstacle at 100kV+ 08-Mar-20 05:42 PM So manual operator could also got serious dose, as he was always near the tube 08-Mar-20 05:49 PM hard to guesstimate dose amounts with the the horrible setup and detector but i wouldn't be surprised if they do not even need to get that rotating anode tube running to end up with serious if not possibly life altering health effects from the exposure they already had 08-Mar-20 05:50 PM Scary part of rotating anode is that they plan to try to power it from 110kV HV transmission line, i.e. with unlimited power 08-Mar-20 05:50 PM wonder if they will all get cataracts in a few months/years 08-Mar-20 05:50 PM that is probably the most obvious thing besides the skin effects they described 08-Mar-20 05:52 PM oh god, I just went to go see that tube at the end, hopefully it just instakills their power supply 08-Mar-20 05:55 PM Power supply will be high-voltage transmission line, so I am pretty sure it will survive... They power heater from battery which will also survive... 08-Mar-20 05:58 PM did they say they were going to use a transmission line? I haven't watched with captions 08-Mar-20 06:05 PM @Treehouseman Yes, at 22:04... 08-Mar-20 06:08 PM Do the tubes need ballasting? Maybe he'll just overload the tube and blow it? 08-Mar-20 06:08 PM honestly just getting access and a tap on a transmission line is a big task, one they'll likely injure themselves trying to do 08-Mar-20 06:26 PM @Treehouseman They already tried that in the past and survived Yeah, if you slowly increase current on filament, it will not overload, but it is a dangerous business. If they go for it - it will be interesting video to watch, once in a lifetime 08-Mar-20 06:26 PM maybe we'll get an xray tube grenade 08-Mar-20 10:11 PM Most x ray transformers are so high impedance on the secondary that they are somewhat self limiting like. Neon transformers are to a certain degree the same way. 09-Mar-20 02:14 AM Neon sign transformers are absolutely impedance limited. I've got one for 15KV and it has a badge right on it saying so. Don't have it with me, unfortunately, but I'll try and remember to take a picture next time. 09-Mar-20 03:42 AM Likely the voltage will sag significantly, right? Or will it just shutdown due to some monitor circuit? 09-Mar-20 03:42 AM Or start oscillating 09-Mar-20 07:24 AM They also don’t know how to S.T.A.L.K.E.R. correctly. They find an abandoned apartment for a base camp, but then proceed to re-activate the electrical wiring, paint the walls, and re-upholster furniture. 09-Mar-20 10:27 AM whoever tried working on this ludlum model 12 before me tried an interesting component swap... changed out a 2N414 transistor for a MPS6534 + zener diode? think this is the blocking oscillator transistor https://i.gyazo.com/8fa2d2c1017a673a31a3e4ecc2cee613.jpg 09-Mar-20 03:20 PM This is a fun article from the field of nuclear forensics. For background, this particular project has been in development since, more or less, 1945 but went into high gear with the testing moratorium in 1992. It has taken a while. https://phys.org/news/2020-03-atomic-fingerprint-emission-sources-uranium.html 10-Mar-20 10:06 PM @Conmega did you end up finding a suitable replacement tunnel diode for your Ludlum model 12? would like to replace the resistors in mine that someone swapped them out with if you have 10-Mar-20 10:26 PM lol they used resistors in yours? I did that as a quick test 10-Mar-20 10:26 PM but I have some russian ones I need to try still 10-Mar-20 10:26 PM they aren't exact replacements but they should hopefully prove close enough 10-Mar-20 10:26 PM I think he's waiting on his micro drill bit to make it past the china quarantines so he can just put a to spec tunnel in a new modern diode 10-Mar-20 10:33 PM yeah someone was in there working on them before I got them, I think 10-Mar-20 10:33 PM posted a photo of the super odd zener/transistor combo that someone swapped in place of a 2N414 yesterday 10-Mar-20 10:33 PM doubt that Ludlum would do that themselves 10-Mar-20 10:33 PM one of them (I have 3) seems totally happy to work with the resistor someone stuck in there and I even managed to calibrate it just sending negative pulses to it. the other two are too temperamental to use though 10-Mar-20 10:36 PM Yea so I believe they were just using the one tunnel diode for making a sharp edge on a signal... 10-Mar-20 10:36 PM I put a resistor in to test and it totally worked... 10-Mar-20 10:36 PM So like I don't think its a crucial part in that area of the circuit, why I am hoping a russian part will work well enough 10-Mar-20 10:40 PM i was surprised that the working one was happy with both geiger tubes and a scintillator and the count rate seemed pretty accurate too 10-Mar-20 10:40 PM has like a 10K resistor in place of the diode 10-Mar-20 10:40 PM yea they just made it a pull up 10-Mar-20 10:40 PM or pull down I can't remember how the diode was functioning 10-Mar-20 10:40 PM but yea so long as you calibrated the voltage for the tube your using should work fine 10-Mar-20 10:42 PM have not worked up the nerve to hook up a He3 tube to it yet to see if it can actually use those without the tunnel diode too, do not really have access to a good source of neutrons to test it with at the moment either 11-Mar-20 01:29 AM https://www.youtube.com/watch?v=3zIiq7upOqw 11-Mar-20 01:29 AM what is wrong with these people on youtube that they feel compelled to play with fine radioactive powders in totally inadequate conditions? 11-Mar-20 01:29 AM better method of transferring the powder this time but now that jar covered in uranium is a whole new problem 11-Mar-20 01:37 AM shakes head sadly 11-Mar-20 01:37 AM Could be worse. I’ll be very happy to never get called to help decon a thorium contaminated meth lab site again. 11-Mar-20 01:39 AM someone in the comments points out that he has an open candy bar when he is messing with the jar...lol 11-Mar-20 01:39 AM that sounds like quite a story with the thorium contaminated meth lab... 11-Mar-20 01:40 AM I am quite happy to say that that particular P2P process had short-lived popularity. 11-Mar-20 01:40 AM Suffice it to say that, in addition to meth, this particular cooking process generated a lot of mixed waste rural counties couldn’t really afford to dispose of when doing cleanup. 11-Mar-20 01:47 AM thankfully not a subject i know much about and hopefully never run into. i try very hard to avoid getting involved with anything that might have complicated hazmat disposal problems 11-Mar-20 01:51 AM That particular cleanup, I asked the county administrator tasked with wrangling it what he would have bought with that money. If I remember right it was something like “This one is a school bus. But over the year so far it’s closer to a fire engine.” Mixed waste is SRS BZNZ. 11-Mar-20 02:01 AM Serious, very expensive business. I’ll take the meth labs with garages filled with ether exploding in July-Sept any day. Sure, keeps the neighbors on their toes, but at least you get to keep the house. 11-Mar-20 01:54 PM Ok, so this might be a dumb question 11-Mar-20 01:54 PM but are there scintillators with a C mount on them? 11-Mar-20 01:54 PM feels like there should be... 11-Mar-20 01:55 PM hehe, like the threaded lens format? 11-Mar-20 01:55 PM yep 11-Mar-20 01:55 PM because I have some HPDs with a tiny 3mm window and C-Mount 11-Mar-20 01:55 PM and since I was not planning to build a single photon detecting surveilance camera I was thinking about other applications 11-Mar-20 01:55 PM also I could maybe glue a scintillator onto a C mount objective 11-Mar-20 01:58 PM https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=9581 thorlabs sells c-mount light-blocking baffles 11-Mar-20 01:58 PM i could also see fiber launch couplers existing in that format too, maybe 11-Mar-20 02:00 PM hmm, I see 11-Mar-20 02:00 PM for scintillating crystals, though, i think you'd want to minimize any air gaps 11-Mar-20 02:01 PM yeah I was just thinking about that 11-Mar-20 02:01 PM why do I need to couple a scintillator to a PMT with gel and whatnot if neither my photon counter nor those HPDs are made for direct coupling 11-Mar-20 02:01 PM if it matters so much with scintillators it would surely matter with single photon stuff 11-Mar-20 02:01 PM oh, it's because of the incident angle, isn't it 11-Mar-20 02:10 PM quickly googling around in lieu of actually working -- poor coupling could also result in increased total internal reflection, which'd result in skewing your pulse heights in the case of a scintillator 11-Mar-20 02:10 PM surely this is also an issue in single-photon counting, though, so idk 11-Mar-20 02:10 PM not sure how scintillator light collection efficiency compares to single photon counting efficiencies (which are in the 20% range, i guess?) but perhaps there's a sacrifice being made between e.g. individual photon time-of-arrival vs. amplitude resolution 11-Mar-20 02:20 PM yep 11-Mar-20 02:20 PM and my train of thought was that a c-mount produces a rather steep angle of incidence on the window, thus resulting in lower total reflection 11-Mar-20 02:20 PM while a scintillator can have light from all directions => coupling needed 11-Mar-20 02:22 PM ah, 'refractive index', that's the word i was looking for 11-Mar-20 02:22 PM i think it's the scintillator glass -> air -> PMT/sensor transitions in refractive index that're the issue 11-Mar-20 02:22 PM i gotta study my optics 101s more 11-Mar-20 02:23 PM yes, that's part of the issue 11-Mar-20 02:23 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/CYb7Hw-fgpglgom6EXgKmkaoogNCgXUojEUmsnX1vv-68782.png 11-Mar-20 02:23 PM the steeper theta 1 the smaller is the amount of light reflected 11-Mar-20 02:23 PM and I think with an objective theta 1 is pretty steep, but with a scintillator it can be everything up to 180° 11-Mar-20 02:23 PM but I have never worked with camera optics, so that's just a guess 11-Mar-20 05:46 PM Thorium catalyzed P2P production :X 11-Mar-20 05:46 PM I actually recall reading about it somewhere. 11-Mar-20 05:46 PM back when I did more amateur/hobby chemistry it was prudent to be aware of what was watched/controlled and what combinations of chemicals ware a bad idea to order at the same time. Especially on ebay. 11-Mar-20 06:08 PM I’ve been in a mindset of “does it need to be ordered? Does it really need to?” 11-Mar-20 08:20 PM The day I saw a certain thorium compound in a lab, I winced, dropped my bag, and pulled out my phone will asking “Show me your controlled substances permit.” They didn’t know they had a DEA scheduled precursor...because it wasn’t when they bought it 30 years ago. 11-Mar-20 09:55 PM Shhhhhhhhh........ hahahahaha.. after my experience with the thorium oxide I did some more digging. It’s still all over being used in things and industries where people aren’t even aware it’s a controlled substance. I thought Marco Rubio was supposed to open that thoria bank where it could all be sent? When is that happening? Hahahaha 11-Mar-20 09:55 PM Oh yeah. Never.... 11-Mar-20 09:55 PM All of this cause quack doctors used to make people Over ingest it. 12-Mar-20 08:06 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200312_160424-2D3A5.jpg 12-Mar-20 08:06 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200312_160456-98C9C.jpg 12-Mar-20 08:06 AM alpha spectra maybe? 12-Mar-20 09:27 AM oh lord, is that why alibaba sells kg-quantities of ThO2 12-Mar-20 09:27 AM naive old me thinking it was for coating.. lots of.. filaments..? 12-Mar-20 09:28 AM what's p2p here? 12-Mar-20 09:32 AM https://www.vice.com/en_us/article/exmg5n/a-comprehensive-guide-to-cooking-meth-on-breaking-bad <-- ctrl+f "thorium" 12-Mar-20 09:32 AM oh no 12-Mar-20 09:33 AM yeah...methheads are the worst 12-Mar-20 09:39 AM @GigaSquirrel what's the spectrum of? radium? 12-Mar-20 09:40 AM radon daughters, I think 12-Mar-20 09:40 AM I put a radium containing stone in a box and electrostatically collected whatever I got 12-Mar-20 09:40 AM the relative peak heights are a bit scewed, because I collected for some time, let it rest for a week (or four) and then collected again 12-Mar-20 09:40 AM but I'm really new to all of this 12-Mar-20 09:40 AM should do an energy calibration, but I only have an Am source, so no two or more point calibration 12-Mar-20 09:52 AM What kind of Am-241 source do you have? 12-Mar-20 09:52 AM If it’s a smoke detector, I’d be concerned that the activity is too high. 12-Mar-20 09:52 AM yep 12-Mar-20 09:52 AM won't give a clean spectrum, but it's "good enough" 12-Mar-20 09:53 AM Aren’t you concerned about contaminating the detector via recoil? 12-Mar-20 09:53 AM reverse bias edition 12-Mar-20 09:56 AM Also, I thought I read somewhere that Am-241 sources in smoke detectors were plated with gold (?) to reduce the risk of loose contamination. The plating would have to be thin enough to allow alphas to escape to ionize the air in the chamber, but that still can cause scattering, smearing peaks downward. 12-Mar-20 09:57 AM also true 12-Mar-20 09:57 AM I'm not talking about absolute calibration, but just order of magnitude thing 12-Mar-20 09:57 AM so I can identify my peaks here 12-Mar-20 09:59 AM Well in that case, doesn’t your alpha detector have specs to indicate the energy range to voltage translation? 12-Mar-20 10:00 AM good point 12-Mar-20 10:01 AM I think mine maps the selected range (4-6 MeV) to 0.25 to 10V. 12-Mar-20 10:03 AM ohh it's got an integrated pulser 12-Mar-20 10:03 AM Your ADC should have specs for how it maps voltage to bins. Typically 0-10V is NIM standard although I have a UCS-20 that only supports 0-8V. 12-Mar-20 10:03 AM yeah it's 0-10V 12-Mar-20 10:03 AM @GigaSquirrel we have the same alpha spec, right? 12-Mar-20 10:04 AM nah I got a canberra one 12-Mar-20 10:04 AM oo 12-Mar-20 10:04 AM That’s good too, although the pulser is not necessarily exactly calibrated to energy. 12-Mar-20 10:04 AM but I also still have those silena chambers 12-Mar-20 10:04 AM you enter the pulser position in MeV 12-Mar-20 10:04 AM CALIBRATION PULSER – Range – 0.1 to 10 MeV, adjustable in 0.1 MeV steps. – Stability – Better than 50 ppm/°C. – Display Resolution – 10 keV. 12-Mar-20 10:07 AM There isn’t a spec for absolute error. Just resolution, range, and temperature stability. 12-Mar-20 10:07 AM I wouldn’t necessarily count on what you dial into the pulser exactly matching what your detector will output for the dialed energy. 12-Mar-20 10:07 AM The pulser could be off by 10% but sill meet those specs so long as it is temperature stable. 12-Mar-20 10:09 AM fair enough 12-Mar-20 10:09 AM I wonder what the calibration is for 12-Mar-20 10:09 AM It’s better than nothing, though. 12-Mar-20 10:09 AM Especially if you don’t have a good check source. 12-Mar-20 10:10 AM yep 12-Mar-20 10:10 AM gonna try that later today 12-Mar-20 10:10 AM Pulsers can also be used to approximate dead time. 12-Mar-20 10:10 AM my mca has a dead time readout 12-Mar-20 10:11 AM Dead time is a lot more complex than that. 12-Mar-20 10:11 AM yep 12-Mar-20 10:11 AM but in my case that's good enough 12-Mar-20 10:12 AM The MCA can tell you how long the ADC is gated off due to conversions, but there’s also the amp, pulse pileups, intrinsic dead time in the detector, etc. 12-Mar-20 10:13 AM I know 12-Mar-20 10:13 AM all I'm saying is that dead time doesn't matter for me at the moment 12-Mar-20 10:15 AM Yeah, if you aren’t trying to do quantitative studies, it isn’t super relevant. And doing quantitative studies typically requires unobtainium isotopes of known activity with which to spike your sample. 12-Mar-20 10:15 AM exactly 12-Mar-20 10:54 AM https://twitter.com/GovNuclear/status/1238146837225373700 12-Mar-20 10:54 AM cool test cell...terrible music 12-Mar-20 11:05 AM tennessee.mp3 13-Mar-20 06:05 AM ohh, interesting 13-Mar-20 06:05 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200313_140615-6B890.jpg 13-Mar-20 06:05 AM those are the calibrator pulses I get without detector bias 13-Mar-20 06:05 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200313_140812-89558.jpg 13-Mar-20 06:05 AM that's what I get with detector bias 13-Mar-20 06:05 AM now who can tell me why they get so much sharper? You'd think they should have the same resolution, because they always come from the same pulser, right? 13-Mar-20 07:47 AM I’ve seen the same behavior on my alpha spec. Without bias, the pulser produces a wider peak. With bias, the peak narrows considerably. I don’t have an explanation. 13-Mar-20 07:49 AM Remove the detector and see how the pulses change 13-Mar-20 07:49 AM also think about what determines noise in a CSA 13-Mar-20 08:00 AM My “home lab” mostly migrated to my friend’s home so I can’t check immediately. My gf is quite happy that the NIM crate is no longer in the living room. 13-Mar-20 08:10 AM Aw, that sucks 13-Mar-20 12:12 PM @GigaSquirrel Had you built your own CSA at some point? 13-Mar-20 12:12 PM yep 13-Mar-20 12:12 PM How’d that work out? 13-Mar-20 12:12 PM ehhh 13-Mar-20 12:12 PM due to my lack of knowledge in electronics it wasn't very good 13-Mar-20 12:12 PM but hold on, I've got a good one here somewhere 13-Mar-20 12:12 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/emirhan2016-01BD6.pdf 13-Mar-20 12:12 PM fig.4 13-Mar-20 12:15 PM Oh hm, I’ll take a closer look at that one 13-Mar-20 12:18 PM that works great for semiconductor detectors, down to 10-20 keV equivalent noise 13-Mar-20 12:18 PM with cooling and a better fet maybe even 1-2 keV 13-Mar-20 12:18 PM keep in mind their 20 keV measure was uncooled, maybe even unshielded and using a BPW34 as spectrometer 13-Mar-20 12:24 PM I'd been looking at a S1223 and potentially trying to cool it using dry ice and acetone. 13-Mar-20 12:24 PM But I think I have a BPW34 or two just in my parts bin already 13-Mar-20 12:25 PM please don't use the bpw34 13-Mar-20 12:25 PM it's a terrible detector and I don't understand why it became so popular 13-Mar-20 12:25 PM the S1223 is ideal, if you remove the glass lense 13-Mar-20 12:26 PM It's cheap and common? 13-Mar-20 12:26 PM but it just doesn't really work as a detector 13-Mar-20 12:29 PM It wasn't in the plans. Anyone have a reliable source for Hamamatsu photodiodes? 13-Mar-20 12:29 PM Could just try ebay but I don't exactly trust it for parts like that 13-Mar-20 12:30 PM Mouser has many 13-Mar-20 12:33 PM I couldn't seem to find any there 13-Mar-20 12:33 PM yeah same I just looked 13-Mar-20 12:33 PM wth 13-Mar-20 12:35 PM No idea either 13-Mar-20 12:36 PM it's not hamamatsu, but the PC50-7-TO8 looks really nice 13-Mar-20 12:36 PM decap this sucker and you can do all kinds of spectroscopy 13-Mar-20 12:37 PM Oh that looks very interesting 13-Mar-20 12:37 PM These would be very interesting to play with but I don't want to think too hard about costs: http://www.osioptoelectronics.com/standard-products/silicon-photodiodes/x-ray-radiation-detectors/soft-x-ray-far-uv-enhanced-photodiodes.aspx 13-Mar-20 12:39 PM I'm pretty sure those are just regular PIN diodes 13-Mar-20 12:39 PM Maybe 13-Mar-20 12:39 PM lol no it's just PN 13-Mar-20 12:48 PM I’ll check out that other diode you linked though, thanks 13-Mar-20 12:52 PM always happy to help 14-Mar-20 01:32 PM I've had good luck with a decapped BPX65 PIN diode 14-Mar-20 01:35 PM doing what exactly? Alpha or x-ray? 14-Mar-20 01:35 PM X-ray 14-Mar-20 01:35 PM and with good luck, do you mean detecting or spectroscopy? 14-Mar-20 01:37 PM Spectroscopy, with a preamp from Cremat and my own shaping amplifier 14-Mar-20 01:37 PM Both at room temp 14-Mar-20 01:37 PM ohhh, interesting! 14-Mar-20 01:38 PM Be aware the count rate is going to be low though 14-Mar-20 01:38 PM yeah the efficiency isn't gonna be great 14-Mar-20 01:38 PM But it's fast! Great for pulsed applications 14-Mar-20 01:39 PM cool! 14-Mar-20 01:39 PM what kinda resolution did you get? 14-Mar-20 01:41 PM ~6 keV FWHM for a Co-60, so not fantastic 14-Mar-20 01:41 PM That's a strong source as well 14-Mar-20 01:41 PM But still took half a day to accumulate counts 14-Mar-20 01:42 PM wait, co60?! 14-Mar-20 01:42 PM no way 14-Mar-20 01:42 PM Fe60 maybe 14-Mar-20 01:45 PM Sorry, it's a Cs-137 source, the same one I used to calibrate the ionization chamber 14-Mar-20 01:45 PM but still 14-Mar-20 01:45 PM that's way too high energy for a detector that small 14-Mar-20 02:05 PM Actually, after some calculations, I think the peak I was actually measuring was the k-alpha photopeak from Ba-137 from the source... 14-Mar-20 02:05 PM That’s insane 14-Mar-20 02:05 PM Oh wait 14-Mar-20 02:05 PM Hmm 14-Mar-20 02:05 PM Which means the noise figure needs to be multiplied by a factor of about 10... 14-Mar-20 02:06 PM yeah 14-Mar-20 02:09 PM It's not trivial how to calibrate the detector actually... I tried multiple bias voltages and kinda ended up confusing myself. The sensitive charge collection volume changes, the noise changes and you end up having to adjust discriminators every time you count 14-Mar-20 02:09 PM It is very sensitive to bias voltage, at least for the CR-110-R2 preamp, a few tens of mV difference can cause the pulses to be drowned out in noise 14-Mar-20 02:15 PM yikes 14-Mar-20 02:16 PM I think leakage current is to blame here 14-Mar-20 02:16 PM But, you still get definite x-ray pulses once you have it dialed in 14-Mar-20 02:19 PM sweet 14-Mar-20 02:19 PM I wanna try doing some gas proportional x-ray spectroscopy one day 14-Mar-20 02:19 PM How do you like that preamp? 14-Mar-20 02:21 PM It was clear that the front end electronics is a lot more important than the photodiode. I've never used another preamp before, so I can't directly compare its performance to anything else. It was really convenient, which I appreciate. 14-Mar-20 02:21 PM https://www.amazon.com/CR-112-R2-1-Charge-Sensitive-preamplifier-Module/dp/B07BCPQG85 14-Mar-20 02:21 PM And relatively cheap 14-Mar-20 02:22 PM Oh shoot that is convenient 14-Mar-20 02:22 PM https://www.amazon.com/CR-150-R5-Evaluation-Sensitive-preamplifier-modules/dp/B07BD4WQJQ 14-Mar-20 02:22 PM This makes it even more convenient and probably will improve your results compared with my equivalent made on a perfboard... 14-Mar-20 02:25 PM just today I've ordered some PCBs for "my" preamps 14-Mar-20 02:25 PM based on this design https://sci-hub.tw/10.1016/j.nima.2016.02.022 14-Mar-20 02:25 PM wanna see how low I can go 14-Mar-20 02:40 PM https://www.analog.com/media/en/reference-design-documentation/design-notes/dn399f.pdf 14-Mar-20 02:40 PM Designing transimpedance amplifiers for large area photodiodes require special techniques due to their large capacitance, but the parts count and cost can be quite a bit lower 14-Mar-20 02:40 PM With a single op-amp design 14-Mar-20 04:28 PM One PIN-diode based low cost spectrometer I heard about had a high impendence J-fet frontend feeding a low noise op-amp 14-Mar-20 04:30 PM https://www.ebay.com/itm/NEW-Si-PIN-Detector-Element-with-PA230-Preamplifier-25mm-2-1mil-Be-Window/123346334252 14-Mar-20 04:30 PM Detector and the J-fet both cooled to -43 degrees Celsius here. Honestly a very good solution considering price vs performance 14-Mar-20 04:30 PM 190 eV - 225 eV FWHM at 5.9 keV 14-Mar-20 04:30 PM The diode is specially made for the purpose as well, so the efficiency should be higher up to higher energies compared to other PIN diodes. 14-Mar-20 04:30 PM Yeah here we go 14-Mar-20 04:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4F74B.png 14-Mar-20 04:30 PM It is worth noting that even if you don't have full energy deposition, you will still see a pulse that will lie within the lower energy spectrum in your MCA 17-Mar-20 03:54 AM ok 17-Mar-20 03:54 AM so 17-Mar-20 03:54 AM I've been watching better call saul 17-Mar-20 03:54 AM and 17-Mar-20 03:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-62547.png 17-Mar-20 03:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-ADD0E.png 17-Mar-20 03:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-11A33.png 17-Mar-20 03:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-57BE0.png 17-Mar-20 03:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8EDF6.png 17-Mar-20 03:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-62C53.png 17-Mar-20 03:54 AM they've taken apart dozends of smoke alarms, blended the Am and distributed it via having it run down their legs 17-Mar-20 03:54 AM "Turns out the radiation level was completely safe" Looks like someone should get fired 17-Mar-20 05:48 AM wut 17-Mar-20 05:48 AM why are they doing it? 17-Mar-20 05:48 AM to devalue a property 17-Mar-20 06:07 AM :V 17-Mar-20 06:07 AM I mean... making a property a superfund is one way to do that... 17-Mar-20 09:52 AM dont think it was really for that reason...it was to cause an OSHA violation and shut down construction 17-Mar-20 09:54 AM yep, they say that later 17-Mar-20 09:55 AM not sure why they didnt have him just grab some uranium ore or something 17-Mar-20 09:55 AM they are in NM... 17-Mar-20 09:55 AM but at least they had semilegit radiation survey sorta gear for that bit 17-Mar-20 09:58 AM yep 17-Mar-20 09:58 AM kindasorta 17-Mar-20 09:58 AM but the radiation was far from safe 17-Mar-20 09:58 AM it's Am dust ffs 17-Mar-20 10:01 AM yeah definitely was not disagreeing about that 17-Mar-20 10:01 AM though the great escape homage was pretty funny 17-Mar-20 10:14 AM didn't catch that 17-Mar-20 10:28 AM that was the dirt dispersal thing with the bag and string in the pants, at least i assumed it was meant to be a reference 17-Mar-20 10:28 AM no reason not to just dump the cup of dust if that wasn't the goal 17-Mar-20 11:15 PM I regret everything about checking this server before going to bed. 18-Mar-20 09:53 AM Uh oh.. fear for yourself or fear for others? Hahahaha 18-Mar-20 09:56 AM bunch of copycats gonna go around stripping smoke detectors to make $$$ in real estate, right ? 18-Mar-20 10:16 AM Fear for having to do work. 18-Mar-20 05:42 PM didnt expect the seller to actually accept my crazy low offer on a group of 4 of these...but they might be the cutest geiger tubes https://i.gyazo.com/7441458787456c6974f6f40ed5b4db6e.jpg 18-Mar-20 05:42 PM not quite as sensitive as i was hoping but decent enough 18-Mar-20 05:42 PM Which ones are those 18-Mar-20 05:42 PM LND714 18-Mar-20 05:45 PM my god they are so cute! 18-Mar-20 05:45 PM now i just need to build a properly tiny geiger counter with them 18-Mar-20 05:45 PM 4 for under $40 shipped also was way too good a deal not to jump on even if they are lacking in sensitivity 18-Mar-20 05:45 PM can not vouch for the listing with the "reduced voltage" tubes on ebay as that was not where mine came from if anyone had that idea 18-Mar-20 05:50 PM now you have to make them into real working "headphone jack geiger counters" 19-Mar-20 02:37 AM Yay I got mail today! 19-Mar-20 02:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200319_103540-DB778.jpg 19-Mar-20 02:51 AM nice :D 19-Mar-20 08:37 AM I’ve got a smol Geiger tube in a wrist watch.... 19-Mar-20 11:50 AM Yay! @GigaSquirrel are the third person I've inspired to start a Nuke Coin collection. You'll be happy to know the old commemorative 10 marks coins featuring important scientist and breakthroughs are quite cheap. 19-Mar-20 11:51 AM I'm sorry to tell you, but it was neither you who inspired me, nor will I start actually collecting them now 19-Mar-20 11:51 AM I wanted a coin like that, because it's interesting in a "nuclear" aspect, not because of its historical value, that's only added bonus 19-Mar-20 11:51 AM next point on the agenda is one of those cubes in haigerloch 19-Mar-20 11:51 AM I got as far as holding one in my hand! 19-Mar-20 11:51 AM but I could not take it with me, as it was the only one in the exhibition in the original cave 19-Mar-20 11:51 AM (haigerloch was the nazi reactor experiment) 19-Mar-20 11:56 AM I’ve been meaning to try and talk the director into doing new silver dimes as a thing for when operators graduate 19-Mar-20 11:59 AM Ooo...Haigerloch. One of the cubes is currently on display in Albuquerque. Pretty sure the NuclearAnthro hasn't licked it yet. 19-Mar-20 12:03 PM yet 19-Mar-20 12:03 PM https://twitter.com/GigaBecquerel/status/1063323750295310337 19-Mar-20 06:04 PM Among the things I would've liked to do in Germany on vacation this year. sigh 19-Mar-20 06:34 PM maybe next year 19-Mar-20 06:34 PM I hope this situation will have resolved by then 19-Mar-20 08:16 PM In the meantime, please consider the joy of 10 marks commemorative coins. 19-Mar-20 08:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-8CBDF.jpg 20-Mar-20 02:37 AM Ohh, nice! 20-Mar-20 02:37 AM I should have one like that of otto hahn somewhere 20-Mar-20 07:24 AM I remember Bionerd23 went on a wild goose chase trying to prospect around Haigerloch based on rumors of where additional cubes were buried. 20-Mar-20 07:24 AM She didn’t find anything. 20-Mar-20 07:27 AM me neither 20-Mar-20 12:42 PM anyone got any Hot Tips™️ for lining up the energy scales on a multichannel analyzer without automatic peak-finding? 20-Mar-20 12:42 PM couple days ago i did this with a little bit of radium, got it mostly right, but i'm having trouble with linearity as i throw other samples at it 20-Mar-20 12:42 PM not sure if 'just use the centroid' is best 20-Mar-20 12:42 PM .. or just 'line it up again every time from available spectrum data' 20-Mar-20 12:42 PM i have two very cold trinitite samples that i want to try and dig out as much data as possible from 20-Mar-20 12:42 PM (this is with NaI, specifically, and the best peak resolution i've seen so far is about 7% on the 202 keV line from Lu176) 20-Mar-20 12:42 PM @GigaSquirrel tysm again for this little crystal, btw 20-Mar-20 12:51 PM heh, sure, I'm glad it found a use and isn't just collecting dust, as it was here ^^ 20-Mar-20 12:51 PM The new package would also contain some detectors, but it will be some time until I can send that 20-Mar-20 12:52 PM oooh 20-Mar-20 12:52 PM .. oh yeah, huh. that whole pandemic thing, rip 20-Mar-20 12:53 PM I mean I could try, officially it should all work, but imo to risk of sth getting lost is too high 20-Mar-20 12:53 PM Are you trying to work out where on each peak to mark or something along those lines? Or am I very off 20-Mar-20 12:54 PM yeah, essentially 20-Mar-20 12:54 PM Like https://twitter.com/profanegeometry/status/1240837550433947648 I want to map these channel numbers as accurately as possible to the actual energies involved 20-Mar-20 12:54 PM it's a bit off there from actual 20-Mar-20 12:54 PM the way that i do it on the series 35+ is by picking two points and saying 'it is this energy here and that energy there' 20-Mar-20 12:54 PM and it performs some manner of arithmetical gesticulation and comes up with a little scaling equation 20-Mar-20 12:56 PM Hmm, was that the source it was calibrated with? 20-Mar-20 12:57 PM naw, i calibrated it against two radium peaks a couple days ago 20-Mar-20 12:57 PM can you do three point calibration? 20-Mar-20 12:57 PM that's what you need if your detector isn 100% linear (and it isn't) 20-Mar-20 12:58 PM Seconding that 20-Mar-20 12:59 PM not sure tbh, i'll check the manual but i am guessing not 20-Mar-20 12:59 PM although i can add and subtract spectra from these datapoints, so if there's some piecemeal way i could do it by hand then perhaps 20-Mar-20 12:59 PM unless the scale of the thing needs to become nonlinear itself in which case i'm probably screwed 20-Mar-20 12:59 PM (.. and need to wait for my level shifters to arrive so i can dump the MCA memory to a computer) 20-Mar-20 12:59 PM how is three-point calibration done? 20-Mar-20 12:59 PM like, manually 20-Mar-20 01:01 PM good question 20-Mar-20 01:01 PM you take three points and fit some functon 20-Mar-20 01:01 PM but if that function is squared, log, root 20-Mar-20 01:01 PM I think maestro gives three values, I always thought that's for a second order polynomial, but I never checked that 20-Mar-20 01:09 PM mm, i'll dig in after work maybe 20-Mar-20 01:10 PM I'm amazed you can do home office 20-Mar-20 01:10 PM I would never have the discipline not to work on my projects 20-Mar-20 01:11 PM it's so difficult 20-Mar-20 01:11 PM in fairness it helps to have a workplace that is constantly on fire 20-Mar-20 01:11 PM "helps" 20-Mar-20 01:13 PM hopefully not literally 20-Mar-20 01:14 PM alas, only the countless dumpster emojis in our work slack are actually on fire 20-Mar-20 01:14 PM usually 20-Mar-20 01:14 PM we did have a UPS transfer switch failure a couple days back that knocked out power to a couple thousand servers in one fell swoop, i imagine that very well might've actually amounted to some small deflagration 20-Mar-20 01:17 PM whoops 20-Mar-20 01:17 PM Oh my 22-Mar-20 08:31 AM https://www.youtube.com/watch?v=M9_wupYj02M I think @funranium might hate this 22-Mar-20 01:53 PM is that a magnetron vacuum gauge right off of a beamline 22-Mar-20 01:53 PM a daring choice indeed 22-Mar-20 01:53 PM oh wait maybe it's an ion pump nvm 22-Mar-20 01:55 PM Heh, I visited one of the Helsinki University accelerators like +10 years ago 22-Mar-20 01:55 PM That one was a soviet one/based on a soviet one thanks to bilateral trade. 22-Mar-20 01:55 PM Definitely not that one, I think. 22-Mar-20 02:02 PM POSITRON PICKLE 22-Mar-20 07:41 PM I've seen Astrid 2 in Aarhus, Denmark. Massive: 22-Mar-20 07:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/a2-1000px-A2803.png 22-Mar-20 07:41 PM But tiny all the same 22-Mar-20 07:41 PM "ASTRID2 with ASTRID on the left. The energy of the circulating electrons in ASTRID2 is 580 MeV, the horizontal emittance is 12 nm and the source is optimized to produce synchrotron radiation in the few eV to 1 keV energy range. Beam lifetime is effectively infinite using top-up of the electron current with ASTRID. The diameter of ASTRID2 is 15 m." 22-Mar-20 07:41 PM It's kind of funny because it doesn't really look like much in person 22-Mar-20 07:41 PM just a bunch of tables with junk all over the place, and some weird concrete walls shielding the nearby hall 22-Mar-20 07:41 PM but then you notice that all the vacuum chambers you see are connected together 22-Mar-20 07:41 PM and that it's... a ring... 22-Mar-20 07:41 PM and has an insane amount of 8020 22-Mar-20 08:46 PM @GigaSquirrel prompts the Accelerator Design Story. Once upon a time, a postdoc was tasked with realizing the decade+ old dream of a few professors to mimic the useful part of the TRIGA neutron output for geochronology and some neutronics experiments with a rather beefy DD neutron generator. Postdoc sits down with his first pass of the design he and the professors have slapped together and wants to see what I think, because if I say no to something the project basically never starts. Me: Well, it looks workable and and the shielding should be adequate, though you're going to need to do some MCNP modeling for that. Postdoc: MCNP, got it. What else? Me: Okay, I know you're a long way from architectural drawings but I have a recommendation for your parts lists. PD: Like what? Got some preferred vendors. Me: No, that would be an ethics violation. This is more like choose your stainless steel wisely relative to activation cross-sections and use as much aluminum as feasible. You'd like to get your entry time down to 20-40min rather than days. PD: WHAT?!!? Me: Right, you need to figure out the elemental composition of every item in the chamber for activation analysis. And you want strict control over what items are allowed to remain in the chamber during runs. The same As Much Aluminum as you can applies. PD: Are you serious? Me: As someone that's dismantled target rooms and accelerators where this consideration wasn't taken into account at the outset, I am very serious. You may only be here for 2-6 years, but your and my successors in 20 in years will curse our names if we don't do this right. Also, this will speed up your cycling time for samples if you don't have to wait day or two for everything to cool down before entry. 23-Mar-20 12:15 AM Entry down time means half life of species that ended up produced by running the instrument?? 23-Mar-20 04:13 AM yeah, like, something like however many half lives need to pass as a function of neutron fluence + neutron exposure duration + however the surrounding environment moderates & subsequently changes activation cross sections along the path of the neutrons, for the elemental composition of everything in the surroundings (probably including subsequent transmutations, i'd guess) 23-Mar-20 04:13 AM waves hands vaguely MCNP 23-Mar-20 04:13 AM although OpenMC recently added a burnup code and i have no idea if that's applicable here 23-Mar-20 04:22 AM recently I was reading some lab's procedure notes for a single crystal neutron diffractometer and they had a blurb about how using any of the cadmium collimator plates would lengthen the amount of time before you could safely re-enter the target area by several minutes, and then i spent the next couple hours in ENDF and frowning at my nuclide chart trying to figure out how they came to that number precisely 23-Mar-20 04:22 AM it did not seem anywhere near as straightforward as just the involved half-lives 23-Mar-20 08:46 AM More the half lives of all the things generated by running instrument, but there's a few that are nasty but die off quickly and a few that progressively grow in and just make working with the machine awful. Ar-41 will lose you a small confined space for ~10hrs, which means ventilation is key to pipe all that out of there. Mn-56 is about a day lost & Cu-64 almost a week for cool down, but those tend to be component issues that make working on the machine annoying more than anything else. In our case, we couldn't get away from some large manganese filled magnets that made the extremity dose rates when loading and unloading samples after a run very unpleasant. Had to run the stopwatch on the students on practice drills like COACH until they got their skills down. :) If you use waaaaay too much steel, and definitely if you chose poorly with your steel grade, you will slowly grow an inhospitable space filled with Co-60. 23-Mar-20 08:47 AM https://twitter.com/GigaBecquerel/status/1242115447723614211 23-Mar-20 12:09 PM niiiice :D 23-Mar-20 12:23 PM thanks 23-Mar-20 12:23 PM works well enough to discriminate between beta and alpha 23-Mar-20 12:23 PM and it's amazing how voltage dependant the gas gain is 23-Mar-20 12:23 PM like sure, you know it is, but it's amazing to see 23-Mar-20 12:44 PM what fill gas are you using, again? 23-Mar-20 12:45 PM heh 23-Mar-20 12:45 PM air 23-Mar-20 12:45 PM the detector is completley open 23-Mar-20 12:46 PM oohh 23-Mar-20 12:47 PM the foil is basically just to stop dirt getting in 23-Mar-20 12:47 PM but I'm thinking about sealing it up and pressurizing some Ar in it 23-Mar-20 12:47 PM or maybe flow 23-Mar-20 01:04 PM tried recirculating the air around whatever that thing you were trying to electrostatically collect particles off of? 23-Mar-20 01:04 PM be interesting to see the count rate growth on a long-duration multichannel scaler 23-Mar-20 01:06 PM oh, interesting thought! 23-Mar-20 01:17 PM actually, on that note, rn i'm trying to measure an incredibly low background sample (tiny trinitite spherule) and i'm realizing i have a lot of variability in background radon in my bedroom depending on when i open doors/etc 23-Mar-20 01:18 PM yep 23-Mar-20 01:18 PM so i'm having some unsavory ideas about 3D printing a new crystal-holder shim+sample chamber that can also take either positive or negative pressure 23-Mar-20 01:18 PM positive 23-Mar-20 01:18 PM when I measure low activity stuff I vent the LN2 evap of my detector into the castle 23-Mar-20 01:18 PM ooh 23-Mar-20 01:18 PM but there will always be some variance 23-Mar-20 01:18 PM and you will always see Rn (and daughters, esp. Bi214) and 511 keV 23-Mar-20 01:18 PM no way around that 23-Mar-20 02:35 PM heh, whoops 23-Mar-20 02:35 PM my mca had an overflow 23-Mar-20 02:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200323_223429-D142E.jpg 23-Mar-20 03:00 PM nice of it to put a frown right in there for you to know 23-Mar-20 03:03 PM XD 24-Mar-20 09:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200324_095208-17F76.jpg 24-Mar-20 09:56 AM thy bins runneth over 24-Mar-20 09:56 AM surprised the software-based thing doesn't at least notify you of that 24-Mar-20 09:58 AM there's a flag somewhere 24-Mar-20 09:58 AM (.. or just outright use bignum channel storage.. ) 24-Mar-20 09:59 AM I can tell it to stop sampling once there's an overflow 24-Mar-20 09:59 AM yeah you see this mca is old 24-Mar-20 09:59 AM still got its memory on board 24-Mar-20 09:59 AM 8k channels times 24 bit 24-Mar-20 10:03 AM ahhh 24-Mar-20 10:03 AM same here, but 4k * 20 bit channels iirc 24-Mar-20 01:18 PM @GigaSquirrel do you have the schematic for that charge sensitive amp you built? been trying to get a feel for some of the different approaches people use for them 24-Mar-20 09:23 PM @GigaSquirrel was that Eluveitie music in the background? I thought I heard a hurdy gurdy.... 25-Mar-20 02:37 AM Good guess, but no 25-Mar-20 02:37 AM it was some Cyberpunk mix 25-Mar-20 03:44 AM https://www.youtube.com/watch?v=G3O-zG_9sWk Must have been that one 31-Mar-20 04:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200331_131248-AE93D.jpg 31-Mar-20 04:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200331_131300-A7F91.jpg 31-Mar-20 04:15 AM hnnf new detectors ❤️ 31-Mar-20 04:15 AM left has preamp and everything already integrated 31-Mar-20 09:46 AM https://www.ebay.com/itm/Bicron-1-25MSW1-22-1-5C-X-Scintillation-Gamma-Radiation-Detector/183740473840 31-Mar-20 09:46 AM anyone know what the deal with the wire coming off of the end is? 31-Mar-20 09:46 AM https://www.ebay.com/itm/Mark-III-Cutie-Pie-CPI-44-Radiation-Detector-Technical-Associates-Homeland-Defen/184210524296 31-Mar-20 09:46 AM ooooooh that is an old detector 31-Mar-20 12:03 PM that wire might be for grounding.. some PMTs are wired so the case floats at anode voltage 31-Mar-20 12:03 PM though weirdly it also looks kind of like a thermocouple.. shrug 31-Mar-20 12:03 PM neat side-well detector though 31-Mar-20 12:03 PM @GigaSquirrel NICE 31-Mar-20 12:03 PM Integrating Cutie Pie oh same 31-Mar-20 03:05 PM sigh 31-Mar-20 03:05 PM That ortec diad detector with preamp and what not 31-Mar-20 03:05 PM also has a protective Al cover of a few nm evaporated onto it, as a light shield 31-Mar-20 03:05 PM and according to the manual that can be cleaned with DI water and tlc 31-Mar-20 03:05 PM apparently some of that dirt was chemically reactive 31-Mar-20 03:05 PM and when cleaning the surface a few flakes of Al came off 31-Mar-20 03:05 PM it still works and all, but it's no longer light tight 31-Mar-20 03:05 PM I might try evaporating new Al onto it some day 31-Mar-20 03:05 PM but until then 31-Mar-20 03:05 PM bleh 31-Mar-20 03:05 PM this was not the end to this day I was hoping for 31-Mar-20 03:36 PM oh nooo 31-Mar-20 03:37 PM yep :v 31-Mar-20 04:14 PM Just use some spray paint, it'll be fine :P 31-Mar-20 04:15 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/2577844-89302.jpg 31-Mar-20 04:16 PM One of these filled with radium paint https://www.michiganmotorz.com/images/preval-267-400.jpg 31-Mar-20 04:17 PM shudders 31-Mar-20 04:17 PM https://giphy.com/gifs/want-tjwzClJM6fyEw 31-Mar-20 04:17 PM well I guess this is as good of a time as any to build a PVD setup 31-Mar-20 04:17 PM it's ~1 µm of Al 31-Mar-20 04:17 PM that sounds doable 31-Mar-20 04:17 PM in the mean time enjoy the last pic I took of the detector fully intact 31-Mar-20 04:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200331_231154-ADAE0.jpg 31-Mar-20 05:16 PM [grumbles] Cutie Pies... 01-Apr-20 09:45 AM lol 01-Apr-20 10:18 PM https://www.ebay.com/itm/Chrismatec-Bicron-Gamma-Detector-Sensor-Probe-32-SPE-50-Wizard-Scintillation/202898715530 01-Apr-20 10:18 PM End well NaI scintillators like these are more convenient than the side well ones for most applications, plus it's cheaper 02-Apr-20 06:28 AM That detector @qualia just posted in #swap-meet ... What exactly is it? The name alone implies a semiconductor detector / PIN diode, but why does it have a photocathode, an anode made of nickel etc? 02-Apr-20 06:28 AM https://hofstragroup.com/product/eg-g-xrd-51-biplanar-high-speed-x-ray-detector-300-ps-with-etched-cathode/ 02-Apr-20 08:07 AM I see! 02-Apr-20 08:07 AM it's a diode, in the vacuum valve / tube kind of sense 02-Apr-20 08:07 AM it's got a photocathode made of Al and an anode made of Ni, that's how it can be so fast 02-Apr-20 08:07 AM https://hofstragroup.com/legacy-assets/3312.pdf 02-Apr-20 08:07 AM that should be very DIYable 02-Apr-20 08:07 AM but it doesn't have an electron multiplier, methinks 02-Apr-20 08:07 AM so getting a signal out of it will be a challenge 02-Apr-20 08:07 AM thanks for nothing 02-Apr-20 08:07 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2F63C.png 02-Apr-20 08:36 AM oh geez 02-Apr-20 08:36 AM that's actually Volts / amps 02-Apr-20 08:36 AM The XRD-31 is a fast, windowless X-ray vacuum photodiode developed by EG&G. It is currently the primary fast X-ray detector used to diagnose the X-rays on NIF and OMEGA on the multichannel DANTE spectrometer. The XRD-31 has a dynamic range of less than 1e-12 amps to more than 10 amps. 02-Apr-20 09:19 AM I kinda wanna build one now 02-Apr-20 10:32 AM Why is the work function of Al so unknown? 02-Apr-20 10:32 AM the values I can find range from 4.06 to over 4.25 eV 02-Apr-20 10:38 AM I would assume that's for various alloys? 02-Apr-20 10:39 AM don't think so 02-Apr-20 10:39 AM should be for the element 02-Apr-20 10:41 AM which elements don't have a range like that? 02-Apr-20 10:41 AM I also don't think unknown is the right word 02-Apr-20 10:42 AM it should be a constant 02-Apr-20 10:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-9E0E2.png 02-Apr-20 10:43 AM Yeah most of the time the work function is not super precise, it's hard to measure accuratly 02-Apr-20 10:44 AM But you want the work function of a single bare aluminum atom? 02-Apr-20 10:44 AM energy levels depend on surroundings 02-Apr-20 10:44 AM it shouldn't be a constant 02-Apr-20 10:44 AM it's not always measurement uncertainty, it varies 02-Apr-20 10:45 AM it should very much be a constant 02-Apr-20 10:46 AM No... 02-Apr-20 10:46 AM there's a difference between the work function and the actual energy it takes an electron to escape 02-Apr-20 10:46 AM the work function is a constant, but the energy needed can be manipulated, with electric fields and whatnot 02-Apr-20 10:47 AM Pretty sure that's not how it's defined 02-Apr-20 10:47 AM electric fields don't have to be external, either. bohr model bad 02-Apr-20 10:49 AM Pretty sure that's how it is defined 02-Apr-20 10:50 AM Source? Everything I can find says energy to remove from a surface 02-Apr-20 10:50 AM In solid-state physics, the work function (sometimes spelled workfunction) is the minimum thermodynamic work (i.e., energy) needed to remove an electron from a solid to a point in the vacuum immediately outside the solid surface. 02-Apr-20 10:50 AM that's literally the first sentence in wiki 02-Apr-20 10:51 AM That literally agrees with me 02-Apr-20 10:51 AM and disagrees with you 02-Apr-20 10:51 AM it is a property of the solid/surface 02-Apr-20 10:51 AM not of the element 02-Apr-20 10:51 AM the structure matters 02-Apr-20 10:51 AM surrounding atoms matter 02-Apr-20 10:51 AM external conditions matter. 02-Apr-20 10:51 AM "Below is a table of work function values for various elements. Note that the work function depends on the configurations of atoms at the surface of the material. For example, on polycrystalline silver the work function is 4.26 eV, but on silver crystals it varies for different crystal faces as (100) face: 4.64 eV, (110) face: 4.52 eV, (111) face: 4.74 eV.[13] Ranges for typical surfaces are shown in the table below." 02-Apr-20 10:51 AM In the table, aren't all the ones with ranges elements that are common in deposition ? 02-Apr-20 10:51 AM i.e. we have better data on the stuff we use more frequently 02-Apr-20 10:54 AM Most of the time what I have seen is that it's listed for a given material state (mono or polycrystals, heat treat) 02-Apr-20 10:54 AM right, we've been talking a bit past each other it would seem, but I think I get now what you're talking about. I agree that a single atom has a different work function than a crystal of the element. but if that crystal is the same the work function will be the same, and if you apply eg. other fields the work function doesn't change, but the actual needed energy 02-Apr-20 10:54 AM But the table you gave is saying "if you have an aluminum surface, the work function will be near this" 02-Apr-20 10:55 AM yes, there's a big unknown 02-Apr-20 10:55 AM and I don't understand why 02-Apr-20 10:55 AM I think you are thinking too much like a physicist, and not enough like an engineer 02-Apr-20 10:55 AM go recruit more bored self-isolated grad students 02-Apr-20 10:55 AM get someone who actually enjoys condensed matter in here 02-Apr-20 10:56 AM What I care is what my piece of material will emit for a given surface state 02-Apr-20 10:56 AM not what the atom does 02-Apr-20 10:57 AM If you care strongly about that, you find a paper measuring it for the same conditions you're creating 02-Apr-20 10:57 AM work function is derived from experimentalists trying to make cathodes IIRC 02-Apr-20 10:57 AM Yes, and the work function is usually listed for a piece of the element and not a single atom, that was a mistake / bad wording on my side 02-Apr-20 10:58 AM The wiki section on temperature dependence sure is sparse 02-Apr-20 10:58 AM Temperature dependence of the electron work function: The electron behavior in metals varies with temperature and is largely reflected by the electron work function. A recent theoretical model for predicting the temperature dependence of the electron work function, developed by Reza Rahemi et al.[20] explains the underlying mechanism and predicts this temperature dependence for various crystal structures via calculable and measurable parameters. 02-Apr-20 10:59 AM Photoelectric work functions were one of Einstein’s areas of expertise. 02-Apr-20 10:59 AM That's why it's always a pain to work with. Because your material is never the same as the one in the reference. And anyway you don't know your temperature that well, and the geomtrical effects make the E field all wonky 02-Apr-20 10:59 AM spend too much time trying to predict thermionic emitter liftime on paper 02-Apr-20 11:00 AM Look up the work of Karl Spangenberg. Photo electric work functions are listed in the book “Vacuum Tubes” from him 02-Apr-20 11:00 AM anyways I think the initial question can be answered by "it's not unknown, we've just played a lot with it to make it vary a lot" 02-Apr-20 11:00 AM if you took any element and a ton of resources, you could probably make a surface with a wildly different work function and still call it that element 02-Apr-20 11:02 AM Just surface finish is enough to change the results 02-Apr-20 11:02 AM from experience 02-Apr-20 11:02 AM And you suffer from log scale fat marker syndrome since you are trying to get slopes on nano-amps and micro-amps if your sample is small 02-Apr-20 11:07 AM https://arxiv.org/abs/1503.08250 02-Apr-20 11:07 AM play around with the aluminum numbers in that, it ranges quite a bit 02-Apr-20 11:08 AM but there has to be some standard conditions at which the work function is usually measured 02-Apr-20 11:08 AM you usually get one number eg. for mohs hardness, eventhough that can change with temp, mechanical stress or similar 02-Apr-20 11:08 AM you get one number for the boiling point eventhough that changes with pressure 02-Apr-20 11:08 AM so why not one number for the work function 02-Apr-20 11:10 AM but there has to be some standard conditions at which the work function is usually measured nope 02-Apr-20 11:10 AM I think because the scaling is more complicated 02-Apr-20 11:10 AM Not really more complicated than hardness, but phase change stuff is usually pretty calculable. Crystal structure stuff is insane 02-Apr-20 01:20 PM @GigaSquirrel It seems the main advantage for these vacuum photodiodes are their robustness to harsh radiation environments and their extremely fast time response 02-Apr-20 01:20 PM https://sci-hub.tw/10.1063/1.1149355 02-Apr-20 01:20 PM Here's a good paper 02-Apr-20 01:20 PM cool, thanks! 02-Apr-20 01:20 PM I was just a bit confused because I assumed it was a semiconductor 02-Apr-20 01:21 PM And yes! You can absolutely build this at home 02-Apr-20 01:21 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-041BA.png 02-Apr-20 01:21 PM Anode is stainless, photocathode is aluminum, filter is beryllium foil 02-Apr-20 01:21 PM They are mostly sensitive to EUV or very soft x-rays though 02-Apr-20 01:21 PM And only works in vacuum (duh) or at least quite low pressures (~1 Torr) 02-Apr-20 01:21 PM Quite a specialty detector, mainly used in intense pulsed x-ray generators or fusion experiments 02-Apr-20 01:35 PM yeah i figured it'd be especially interesting to the few other pinch/focus folks here 02-Apr-20 01:35 PM i've already got my hands full with getting my RAE MCP detector working.. might be building a quartet of CSAs for it soon 02-Apr-20 02:04 PM How big is your MCP? Pictures? 02-Apr-20 02:07 PM https://twitter.com/profanegeometry/status/1233475101061939205 25mm active area 02-Apr-20 02:07 PM it's a quantar 3300 with the isolated front ring option 02-Apr-20 02:07 PM https://twitter.com/profanegeometry/status/1245673200010186752 i puzzled out the feedthroughs and then found a manual, as is tradition 02-Apr-20 02:08 PM Very nice! 02-Apr-20 02:08 PM it showed up here in #swap-meet and i dove facefirst on it 02-Apr-20 02:08 PM tbh mostly just for the feedthroughs, to use for driving & probing an ion trap, but.. 02-Apr-20 02:08 PM this thing's probably in disrepair and sure has sat in atmosphere for who knows how long.. needs a very careful dusting, then to spend a couple days/weeks in 10^-7 torr + a bake probably 02-Apr-20 02:10 PM Would love to see a picture of it under a good microscope 02-Apr-20 02:11 PM i still don't have an optical microscope 02-Apr-20 02:11 PM but, agreed 02-Apr-20 02:11 PM feels like everyone else is swimming in various microscopes... though getting a friend's SEM back in working condition is way down on the backlog of stuff-that-needs-doing 02-Apr-20 02:20 PM @GigaSquirrel Here's a paper that has measurements for the quantum yield of electrons specifically in the vacuum photodiode application: 02-Apr-20 02:20 PM https://sci-hub.tw/10.1063/1.1147692 02-Apr-20 02:20 PM Have to say, tungsten at a small angle looks awfully good 02-Apr-20 02:29 PM pretty cool stuff, I wasn't aware of those detectors 02-Apr-20 03:49 PM that's such a cool thing 02-Apr-20 03:49 PM if I was on the same coast as you qualia I'd totally let you use any of my microscopes to look at that thing, I'd also love to see the structure of it 03-Apr-20 12:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/EUs7gFNWAAAG406-502A7.png 03-Apr-20 12:45 PM Fun fact at some point the nuclear waste retreatment people were looking at selling xenon from U decay 03-Apr-20 12:45 PM Xenon is so expensive that apparently it sort of made sense financially on paper 03-Apr-20 12:45 PM especially with the current demand for space propulsion 03-Apr-20 12:48 PM too bad you don't get any stable xenon from that 03-Apr-20 12:50 PM stable enough right? I am not a nuc person at all 03-Apr-20 12:50 PM also not from reactors from waste retreatment 03-Apr-20 12:50 PM I remember that they were saying isotope composition was a bit heavier than normal 03-Apr-20 12:50 PM Ok just looked it up, they did not want to sell the Xe-135 (the poisoning one) but the Xe-133 03-Apr-20 12:50 PM or maybe not, I can't recall 03-Apr-20 09:35 PM Wow.. you have to have lots of material to generate enough to do anything with. We had an ampoule of it connected to one of the pumps at the factory for filling xenon rectifiers. It was from Linde. That one ampoule was like over $100 in the 70’s!!!! Of course it could make dozens of tubes but still. They did not make those tubes in more than small quantities. All of them came off that one small 4 port pump. 03-Apr-20 10:19 PM wow... 04-Apr-20 12:52 AM They have enough https://en.wikipedia.org/wiki/La_Hague_site 04-Apr-20 10:50 AM I like how Greenpeace gave up protesting the place for technical reasons. I guess enough people explained to them that it was way safer to process the waste there over just having other countries store it in leaky barrels or just dump it. 04-Apr-20 11:10 AM Or they did not want the current Rainbow Warrior sunk. 04-Apr-20 01:07 PM My parents boat was tied up next to Curve of Time for a while! 05-Apr-20 01:05 PM https://www.dw.com/en/chernobyl-radioactive-forest-near-nuclear-plant-catches-fire/a-53019394 05-Apr-20 01:05 PM https://civilpedia.org/p/?pid=309&t=p&h=Nuclear+Bomb+Detector 05-Apr-20 01:11 PM that is super cool 05-Apr-20 01:11 PM the detector not the fire 05-Apr-20 01:12 PM I'm just drooling at that bank of He3 detectors 05-Apr-20 01:12 PM that background rate! 05-Apr-20 01:12 PM Oh geez 05-Apr-20 01:12 PM https://www.youtube.com/watch?v=mh5NcsxwaaM 05-Apr-20 01:12 PM @funranium will definitely hate that 05-Apr-20 01:12 PM so should everyone else 05-Apr-20 01:12 PM United Space Pirates 3 months ago Why doesn't anyone bother wearing gloves when handling toxic elements? 05-Apr-20 01:12 PM jaynes network 3 months ago Galen Winsor used to eat Uranium when he gave his talks, as he toured this country.. Nuclear energy is Safe.. but the powers-that-be want you to be helplessly dependent and enslaved to their evil bureaucracy! Radiation is your friend and is possibly the only source of energy that can save this world.. If you believe in the global-warming-scam.. then you should support nuclear energy! Gasoline is not bad.. and it is not a 'fossil fuel' either.. Everything you think you know.. is a LIE! There may be another hope as well.. given to us by Nikola Tesla.. but I will not talk about this alt energy at this time... There is one thing that is certain.. giving politicians too much power will be the demise of us all.. and allowing them to tax us to breath, with their phony carbon tax, will only help them finance their criminal-global one world dictatorship of evil! The only solution is that we must all become self sufficient.. and kill the parasite that invades our very minds and souls! 05-Apr-20 01:12 PM jfc 05-Apr-20 01:12 PM https://www.youtube.com/watch?v=wFIVgknHQ_o 05-Apr-20 01:12 PM screams internally 05-Apr-20 01:12 PM f this 05-Apr-20 01:12 PM screams externally 05-Apr-20 01:20 PM So you’ve got a moderated thing of thorium 05-Apr-20 01:21 PM why do these things exist 05-Apr-20 01:21 PM why do these people exist 05-Apr-20 01:21 PM might be one of the worst examples of the Galen Winsor crowd ive seen too... 05-Apr-20 01:26 PM those people do more damage to everything nuclear than the anti nuclear crowd will ever even be able to 05-Apr-20 01:26 PM not to mention the physical damage they cause 05-Apr-20 04:04 PM After all those bad news 05-Apr-20 04:04 PM http://www.nuclearphysicslab.com/npl/npl-home/experiments/half-life-of-excited-np237m-via-the-alpha-gamma-method/ Man, this is sexy 05-Apr-20 05:33 PM Re: Chernobyl, yes, forest fires are common. 05-Apr-20 05:33 PM The place can get tinder box dry. 05-Apr-20 05:33 PM On my 2015 trip, we observed one. 05-Apr-20 05:33 PM Our guide changed direction and started hiking towards this, trying to help pinpoint it, until we saw a helicopter, so we knew it had been spotted. 05-Apr-20 05:33 PM I’m meanwhile thinking, if I can smell smoke, that means I’m breathing in radioisotope-contaminated plant matter. My P100 respirator was back in the van. Is this really a good idea? 05-Apr-20 05:33 PM In 2013, I had a chance to climb a fire tower with a view of Duga. They would have some sitting up there watching for fires in the surrounding forests. 05-Apr-20 05:33 PM There had been talk that Russian separatists were intentionally setting fires in the Zone. I have no idea whether it’s true or not. Blame foreign enemies for anything that goes wrong is a common trope. 05-Apr-20 05:33 PM It seems everyone over there smokes. Careless tourists, careless stalkers, illicit metal scrapping operations, not to mention natural causes.... 05-Apr-20 08:50 PM https://www.youtube.com/watch?v=ZBHIp967TD8 05-Apr-20 08:53 PM I’m not sure if he did but did he talk about any of the regulatory stuff regarding those sources? 05-Apr-20 09:01 PM Because even cracking things open like that feels a little questionable 05-Apr-20 10:37 PM those are cute little things, i made one a few years back 05-Apr-20 11:49 PM @Addison-110m nope, just talked about how the item was fabbed in an accelerator to make it easier to keep the manufacturing process safe 05-Apr-20 11:51 PM Great, hopefully people have enough sense not to try dissolving one of those 05-Apr-20 11:51 PM Now I want to know if people have thought of making a FIB with an alpha particle source 05-Apr-20 11:51 PM FIB? 05-Apr-20 11:52 PM Focused ion beam 05-Apr-20 11:52 PM http://diyhpl.us/~nmz787/pdf/smi3200/pics.html 05-Apr-20 11:52 PM https://imgur.com/a/YQwPaMe 05-Apr-20 11:54 PM Hmm, interesting 05-Apr-20 11:54 PM Most use gallium liquid metal sources for the negative ions 05-Apr-20 11:54 PM Some use xenon plasma 05-Apr-20 11:54 PM Some neon or helium 05-Apr-20 11:55 PM But using an alpha emitter as the ion source? 05-Apr-20 11:56 PM That's my thought 05-Apr-20 11:56 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200405-235629-B889B.png 05-Apr-20 11:56 PM It'd be interesting to see how it would compare 05-Apr-20 11:56 PM With the neutron, would it mill faster? 05-Apr-20 11:56 PM Have weird contamination of the milled surface 05-Apr-20 11:58 PM There’s also maybe the issue that they’re being emitted at fairly high energy 05-Apr-20 11:58 PM Seems like an Everhart Thronley detector would be able to sense them for imaging 05-Apr-20 11:58 PM Well the high energy seems interesting in terms of mill rate and focus stability 05-Apr-20 11:58 PM Or at least spot size 05-Apr-20 11:58 PM I think 05-Apr-20 11:58 PM I found this https://www.irb.hr/eng/Divisions/Division-of-Experimental-Physics/Laboratory-for-ion-beam-interactions/Articles/Nuclear-microprobe 05-Apr-20 11:58 PM Thinking back to that video, it was saying that the strong source from the antistatic thing was only like 15nA induced current... My fib's smallest beam current is kust under 1pA 05-Apr-20 11:58 PM So maybe such a beam would take forever to image or mill 05-Apr-20 11:58 PM Oh wait 05-Apr-20 11:58 PM I'm dumb 06-Apr-20 12:06 AM are those numbers spun around? 06-Apr-20 12:06 AM That means it would be as fast as on of the medium to largeer apertures 06-Apr-20 12:06 AM My fib can do max of 20nA 06-Apr-20 12:06 AM With the polonium having no 30kV power supply requirment... 06-Apr-20 12:06 AM That would make things a little easier, maybe 06-Apr-20 12:09 AM Would the size of the source matter? 06-Apr-20 12:09 AM Physical size 06-Apr-20 12:17 AM Yeah I guess 06-Apr-20 12:17 AM Fib with gallon is a Taylor cone field emitter sort of thing 06-Apr-20 02:03 AM wow, I did not expect applied science to handle sources like that... 06-Apr-20 02:03 AM also I always thought you only rent those staticmaster thingies? 06-Apr-20 04:24 AM Any guesses? 06-Apr-20 04:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-FB888.png 06-Apr-20 05:56 AM @nmz787 For a FIB ion source, the brightness parameter is the most critical. The higher the current, smaller the source size and more directional it is, the better 06-Apr-20 05:56 AM The liquid metal ion sources or gas field ion tips have virtual source sizes on the order on nanometers, these alpha emitters are much larger than that 06-Apr-20 05:56 AM So you just cannot focus the current down to a spot small enough to get useful resolution. 06-Apr-20 07:02 AM @GigaSquirrel I've done some radon sampling with activated charcoal canisters, I think it's applicable to iodine-131 as well. Will you be filling that thing with charcoal? Or is it just an adaptor? 06-Apr-20 07:06 AM I'll put a piece of filter paper ontop 06-Apr-20 07:06 AM that's the normal way for air sample collection 06-Apr-20 07:12 AM Ah, what are you expecting to see under your HPGe? 06-Apr-20 07:12 AM there's a big difference between what I expect to see and what I hope to see 06-Apr-20 07:12 AM I expect to see Rn and daughters 06-Apr-20 07:13 AM I remember finding the spectra somewhere of when the reactor air filters picked up iodine from Japan years ago 06-Apr-20 07:14 AM I hope to see some Be-7, maybe maaaaaaaaaybe some synthetics from cherbobyl, the wind should be just right and the current fires might bring something in the air 06-Apr-20 07:16 AM Hmm I thought using charcoal canisters is the default way for environmental radon sampling 06-Apr-20 07:17 AM for radon yes, but I'm looking for particles / dust 06-Apr-20 07:18 AM Ah yes, from the fires, and you probably want as little radon as possible just from your environment 06-Apr-20 07:19 AM Nice thing about radon though is you can just wait a few days to let it decay and recount 06-Apr-20 07:19 AM yep 06-Apr-20 07:20 AM Every single air filter I’ve ever changed has been covered with radon daughter products. 06-Apr-20 07:21 AM you don't even need to leave the basement, just look at the Rn background to determine what weather you're having 06-Apr-20 07:21 AM Favorite miniature “project” I’ve ever done was counting fresh snow 06-Apr-20 07:22 AM oh good point 06-Apr-20 07:22 AM lots of tiny air filters that went through the while atmosphere 06-Apr-20 07:25 AM Yeah, unfortunately we didn’t have any this winter 06-Apr-20 08:08 AM Yes, I really did hate that @GigaSquirrel. Thank you for reminding me that I hated it when I first saw it for Christmas. I had not seen that stellar 33rd Degree Brain Genius comment however. 06-Apr-20 08:09 AM https://giphy.com/gifs/hqg-tXTqLBYNf0N7W 06-Apr-20 09:17 AM https://www.ebay.com/itm/Vintage-Precision-Radiation-Interments-Model-111B-Scintillator-SBX-11A/143555438677 06-Apr-20 09:17 AM that is a pretty neat looking and very old scintillator 06-Apr-20 09:17 AM like its out of a scifi show from the 60s 06-Apr-20 09:18 AM Holy cow that’s pretty 06-Apr-20 09:28 AM telling myself i dont need either of these things 06-Apr-20 09:28 AM here is another one... with the "De Luxe" scintillator 06-Apr-20 09:28 AM https://www.ebay.com/itm/Vtg-Uranium-Detector-Precision-Radiation-Instruments-111B-Deluxe-Scintillator-LA/324120236458 06-Apr-20 09:28 AM 1.5x1" NaI(Tl) it seems based on squinting at the manual page 06-Apr-20 09:36 AM https://www.orau.org/ptp/Library/InstrManuals/PRI%20i111b%20and%20117.pdf 06-Apr-20 10:44 AM What’s the odds the crystals are still any good? 06-Apr-20 10:44 AM Are they healing crystals? 06-Apr-20 10:44 AM Those are going for good money right now 06-Apr-20 10:50 AM himalayan salt boom? 06-Apr-20 10:50 AM Having a couple witchy friends I’ve had a few very funny conversations about detectors 06-Apr-20 10:51 AM When I saw “negative ion” mentioned in connection with FIB, my first thoughts immediately went to the modern quack medical garbage sold on eBay that may or may not contain thorium.... 06-Apr-20 10:51 AM @Addison-110m you’ve got my attention. What did they say? 06-Apr-20 10:53 AM Nothing really of note, just a really a few jokes after a bit of initial “wait what?” 06-Apr-20 10:56 AM Ok.... I was wondering if they had qabalistic or astrological correspondences to sodium iodide or germanium.... 06-Apr-20 10:57 AM Not that I’ve been aware of 06-Apr-20 10:58 AM Although I suppose what we do could seem quite occult. Looking for tiny flashes of light in crystals to discern information about unseen phenomena.... 06-Apr-20 12:41 PM @Addison-110m as a witchy critter myself, the novelty of going from 'oh pretty this rose quartz makes a nice massage wand/this thing Feels Nice/[insert woo here]' to 'listening to the rainbows of radioactive decay with poisoned salts' is really quite delightful tbh 06-Apr-20 12:41 PM also now quite thankful i went through a Mortar and Pestle phase bc now i can levigate some beach sand into optical polishing media :D 06-Apr-20 12:52 PM we're all just ouija-boarding around segre charts anyways, monte carlo simulations for days. we're all working a very real kind of magic in our own particular way 06-Apr-20 12:56 PM I imagine it really could be delightful. I may also have run a detector over one of their shelves at one point just out of idle curiosity. 06-Apr-20 12:57 PM sensible ^.^ 06-Apr-20 12:57 PM a friend keeps a bit of trinitite on their altar, been thinking about offering them an assay of it if i get the chance 06-Apr-20 01:02 PM What do they keep it there for? 06-Apr-20 01:02 PM Seems like an interesting choice for sure 06-Apr-20 01:06 PM quote: we kin slotin's screwdriver 06-Apr-20 01:06 PM knowing them, that's about right 06-Apr-20 01:06 PM I’m just going to say cool and not ask more questions 06-Apr-20 01:07 PM hehehe 06-Apr-20 01:18 PM @GigaSquirrel oh i love that Np237m coincidence experiment 06-Apr-20 01:18 PM the graph at the end that shows the broadening of a coated smoke alarm source vs. a bare one is very eye opening 06-Apr-20 01:19 PM not only the Experiment itself, but also just the aesthetics of it 06-Apr-20 01:19 PM yeah I didn't think they would loose that much Energy 06-Apr-20 01:19 PM http://www.nuclearphysicslab.com/npl/wp-content/uploads/IMG_3564-rotated.jpg this picture speaks to me 06-Apr-20 01:22 PM not enough random connectors 06-Apr-20 01:24 PM those aren't random 06-Apr-20 01:24 PM microdot to bnc to bnc to bnc to cf to bnc 06-Apr-20 01:25 PM yeah it makes total sense 06-Apr-20 01:25 PM just the scrungy BNC couplers in the UHV side of the chamber is novel to me 06-Apr-20 01:25 PM though this is almost certainly not a UHV application 06-Apr-20 01:26 PM you can tell by the rubber gasket 06-Apr-20 01:41 PM For years floating around our shop we had a 2 prong mains plug to BNC connector cable that would randomly move from station to station. Primarily for comic effect... we did float a scope and actually use it to look at the line voltage one time though. 06-Apr-20 01:48 PM heh 06-Apr-20 01:49 PM Honestly, I’ve needed one of those a couple of times 06-Apr-20 01:49 PM i have to do some scary electrical work on an auxiliary breaker box in my sunroom/lab area.. recently discovered it's been electrically hot since i moved in. was considering sneaking a current transformer around a leg of it while i have it off and apart 06-Apr-20 01:49 PM keep an eye on my noise emissions right at the tap 06-Apr-20 01:50 PM Psychology department has something they get out for a week every fall that raises hell in the power lines 06-Apr-20 01:51 PM Heh. A friend has a trigrature hybrid that has a a Schuko plug as the output 06-Apr-20 01:51 PM student-size skinner boxes 06-Apr-20 01:51 PM For using twisted trilead (aka extension cord) as a feedline for his 3.5MHz band tripole antenna 06-Apr-20 01:51 PM Lunch box sized thing with type N at one end and a Schuko pigtail as the output 06-Apr-20 01:52 PM very good etherkiller vibes 06-Apr-20 01:52 PM Dude is a massive troll when it comes to circularly polarized antennas. 06-Apr-20 01:52 PM And likes trigraturic things as it messes with peoples minds. 06-Apr-20 01:52 PM In addition to circularly polarized antennas genuinely being good for low band NVIS HF stuff 06-Apr-20 01:53 PM first i've heard of it 06-Apr-20 01:53 PM Much less fading 06-Apr-20 01:53 PM As the ionosphere seems to circularly polarize HF transmissions as they reflect form it 06-Apr-20 01:53 PM So using an optimized antenna for that gives you less fading compared to a linearly polarized antenna 06-Apr-20 01:53 PM The price is either a 90* phaseshift box with relays and a double dipole. 06-Apr-20 01:53 PM Or a trigrature hybrid and a tripole 06-Apr-20 01:53 PM But this is not radiation related. 06-Apr-20 01:56 PM 'trigrature' doesn't even return any relevant google hits 06-Apr-20 01:56 PM well, not ionizing radiation, but.. :P 06-Apr-20 01:56 PM #off-topic-thats-sometimes-on-topic -> 06-Apr-20 05:22 PM @qualia I'm witchy too.... It's funny you should mention that. I had a collection of stuff on my mantle, sandwiched between other altars, and I realized it had become an altar in its own right to the Manhattan Project egregore. 06-Apr-20 05:22 PM Leo Vartanian CP-1 lithograph, CP-1 graphite paper weight, tube of CP-1 mechanical pencil graphite, some uranium glass and glazed ceramics, and a circuit board from a Saturn V LVDC. (That's stretching things, but I consider the Apollo Program a part of the nuclear arms race.) Now that I think about it, moving my trinitite collection there would be appropriate. 07-Apr-20 01:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DA299.png 07-Apr-20 01:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-38C82.png 07-Apr-20 01:21 AM this has to be the biggest part I've ever printed 07-Apr-20 09:41 AM Really cool though, interested to see how it works out 07-Apr-20 09:45 AM It didn't 07-Apr-20 09:45 AM Damn 07-Apr-20 09:46 AM TIL: axial fans are terrible at creating a vacuum 07-Apr-20 09:46 AM but version 2 is on its way, using s side channel blower 07-Apr-20 09:47 AM Well I hope that one works well 07-Apr-20 09:47 AM Did you do something with electrostatic collection of airborne radioactive particles or was that someone else I saw? 07-Apr-20 09:53 AM I did electrostatic collection of Rn daughters 07-Apr-20 09:53 AM but not from open air, but from some U ore in a closed chamber 07-Apr-20 09:54 AM Ah 07-Apr-20 10:48 AM @GigaSquirrel your original fan might perform better if you connect it to your reducing filter adapter with a longer length of tubing, giving it a longer region to develop static pressure in 07-Apr-20 10:48 AM like if you have some .. idk, dryer hose kicking around someplace 07-Apr-20 10:49 AM hmm, good point 07-Apr-20 10:49 AM sadly I don't have a tube like that 07-Apr-20 10:50 AM but a squirrel-cage blower's probably the right tool for this job 07-Apr-20 10:50 AM and the blower is already ordered, sooo... ^^ 07-Apr-20 10:50 AM ah well :3 07-Apr-20 10:52 AM my collection of general purpose blowers and fans isn't that big, so I guess one or two specimens could not hurt 07-Apr-20 10:52 AM This type, I found a datasheet to a similar one and that does 100 mbar (differential, I assume, absolute would be insane) 07-Apr-20 10:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/s-l1600-E7BE5.png 07-Apr-20 11:03 AM ooh 07-Apr-20 11:03 AM chonky 08-Apr-20 03:57 AM ok, quick question 08-Apr-20 03:57 AM https://www.mesytec.com/products/neutron-scattering/MPSD-8.html 08-Apr-20 03:57 AM Power consumption: 2.6 W at ±6 V, allows operation in vacuum 08-Apr-20 03:57 AM IN WHAT USE CASE DO YOU THROW A NIM BIN IN A VACUUM CHAMBER 08-Apr-20 04:49 AM When you want really short cables. 08-Apr-20 10:39 AM it looks like they also have a non-nim version 08-Apr-20 10:39 AM also what a module, gosh 08-Apr-20 10:46 AM all the stuff they have... 08-Apr-20 10:46 AM readymade readouts for position sensitive neutron detectors... 08-Apr-20 10:58 AM i need something similar for my microchannel plate 08-Apr-20 10:58 AM turns out finding matched quads of preamplifiers is.. not trivial 08-Apr-20 11:04 AM well 08-Apr-20 11:04 AM https://www.mesytec.com/products/nuclear-physics/MPR-16L.html 08-Apr-20 11:04 AM also that csa I posted in #resources is fairly match-able, just match the two output transistors as well as the feedback C 08-Apr-20 11:18 AM okay lemme rephrase.. finding a matched quad for an ebay pittance, specifically 08-Apr-20 11:20 AM ahhh 09-Apr-20 03:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200410_002837-FF7DC.jpg 09-Apr-20 03:30 PM speaking of preamps... 09-Apr-20 04:01 PM oooo 09-Apr-20 04:12 PM now I only need some feedback caps 09-Apr-20 04:12 PM the store I got the rest of the components from didn't have mica caps below ~1 nF and mouser wants 2.5 bucks a pop 09-Apr-20 04:12 PM oh right there was a company close to me that does mica caps 09-Apr-20 04:12 PM they sent me some samples and were generally very nice 09-Apr-20 04:12 PM https://www.bmc-electronic.de/glimmer.htm Might be interesting for some folks here as well 09-Apr-20 04:18 PM Oh cool! Could you share the board layout for those? 09-Apr-20 04:18 PM sure! 09-Apr-20 04:18 PM can I just upload the eagle files herE? 09-Apr-20 04:18 PM lemme go to my pc 09-Apr-20 04:18 PM If it lets you 09-Apr-20 04:18 PM Thanks! 09-Apr-20 04:24 PM uploaded it in #resources 10-Apr-20 03:34 PM So someone shared a video about polonium 210 antistatic brushes last sunday. I just looked again and they're all now sold out on amazon. 10-Apr-20 03:34 PM That's not concerning at all 10-Apr-20 03:41 PM oh geez 10-Apr-20 03:41 PM oh no 10-Apr-20 03:41 PM that video showed how to take them apart, or rather showed them all taken apart 10-Apr-20 03:42 PM I really hope they only had like 2 or 3 in stock 10-Apr-20 03:42 PM And it felt like it never gave any warning of maybe why you shouldn’t 10-Apr-20 03:43 PM yeah definitely didn't 10-Apr-20 03:43 PM quite the opposite, explained why they were so safe 10-Apr-20 03:44 PM Which yes, if they’re used properly 10-Apr-20 03:44 PM At least it’s a short half life 10-Apr-20 03:47 PM long enough to hurt someone 10-Apr-20 03:49 PM Fair, but at least the lasting cleanup hazard won't be too bad. And if someone buys one, gets bored before they hurt themselves and puts it on a shelf 10-Apr-20 03:49 PM @funranium You seen this? 10-Apr-20 03:51 PM I'm a bit confused, esp. since ben already got into trouble with some regulatory people over his x-ray stuff 10-Apr-20 03:53 PM So am I honestly 10-Apr-20 03:53 PM maybe funranium pissed him off and this is his way of getting revenge 10-Apr-20 04:06 PM He got into trouble for the xray? 10-Apr-20 04:13 PM yeah his ct and backscatter stuff 10-Apr-20 07:36 PM Did he ever post a video about getting in trouble and what that entailed? 11-Apr-20 12:09 PM This is the guy who CT scanned a frozen chicken? 11-Apr-20 12:40 PM yep 11-Apr-20 12:42 PM This is the problem with YouTube and stuff. It’s one thing to do this sort of stuff to develop a process or skill to perform a task we can use. It’s another to do it and show it off to become popular and encourage people who have no business doing these things to do truly dangerous things. 11-Apr-20 12:42 PM What was the issue with the CT scan? I don't know anything about x-ray safety appart from don't eat too much of it 11-Apr-20 12:43 PM Imaging X ray systems are supposed to be registered. 11-Apr-20 12:43 PM At least here they are 11-Apr-20 12:46 PM safety relativism exists at all levels 11-Apr-20 12:49 PM Oh. En regard to CT scans. They expose you as if you were getting a very lengthy X ray. Just a few can exceed your yearly exposure limit. 11-Apr-20 12:49 PM It’s nothing to really worry about as if you have a chronic condition such as a tumor you are probably getting MRI’s anyways. But it occasionally is an issue. 11-Apr-20 12:53 PM Yeah but if you do it on a frozen chicken while you stand in another room seems like it should be fine? 11-Apr-20 01:58 PM Yes, but do everybody attempting to build the same know that? And do so? 11-Apr-20 02:07 PM Sure, but not much you can do about other people. My view on that is that you can't control idiots. As long as the demo was done safely you can't blame the person who published the video 11-Apr-20 02:10 PM I’d argue there’s a duty that if you’re saying a thing is easily available and you can go to a specific place to get it, that you should address some degree of safety 11-Apr-20 02:11 PM If bleach and ammonia didn't say all over the bottles not to mix them 11-Apr-20 02:11 PM and you demonstrate that by mixing them you get this cool thing that can do some cool thing 11-Apr-20 02:11 PM It would be irresponsible not to mention what else you get. 11-Apr-20 02:13 PM There’s also the self interest of “if someone does something stupid inspired by a thing I did, it might reflect pretty poorly on me” 11-Apr-20 02:14 PM Because society agrees there is some level of responsibility required 11-Apr-20 02:22 PM I keep my stupid stuff private. so I don't have this issue. But maybe I have too high hopes on what people are doing after looking at youtube videos 12-Apr-20 09:39 AM https://www.orau.org/ptp/collection/proportional%20counters/bf3chalklarge.htm owo so big 12-Apr-20 09:39 AM but I'm a bit surprised by the low fill pressure 12-Apr-20 09:39 AM 250 mbar 12-Apr-20 09:55 AM Bad link, @GigaSquirrel 12-Apr-20 09:55 AM huh 12-Apr-20 09:55 AM works for me 12-Apr-20 09:55 AM https://www.orau.org/ptp/collection/proportional%20counters/Proportionalcounters.htm Does this work for you? 12-Apr-20 10:07 AM Both give me 404’s 12-Apr-20 10:11 AM huh 12-Apr-20 10:11 AM what the hell 12-Apr-20 10:11 AM works for me and some friends of mine 12-Apr-20 10:11 AM error must be on your side, somehow? 12-Apr-20 10:13 AM It works for me too 12-Apr-20 10:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D149F.png 12-Apr-20 10:13 AM Dead on my end too 12-Apr-20 10:18 AM works here 12-Apr-20 10:19 AM Ryan, were you trying to open it on mobile? 12-Apr-20 10:21 AM Yes, on an iPad. 12-Apr-20 10:22 AM That might have been the problem then. I was able to open it fine out of discord for whatever reason 12-Apr-20 10:28 AM Weird 12-Apr-20 10:28 AM I thought 400 errors were always something on the servers side? 12-Apr-20 10:29 AM Might be the browser trying to go to the wrong place 12-Apr-20 10:29 AM may be 12-Apr-20 10:29 AM dunno 12-Apr-20 10:29 AM regardless, that's one hell of a detector 12-Apr-20 10:31 AM And there's 6 of them, in one big poly block 12-Apr-20 10:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-357BA.png 12-Apr-20 10:33 AM damn 12-Apr-20 10:33 AM You could build a house with that, just take modules like this as ready made walls 12-Apr-20 10:34 AM Weighs literally 10 tons with its lead producer 12-Apr-20 10:34 AM https://sci-hub.tw/10.1139/p64-222 12-Apr-20 01:18 PM Link works here on android from discord app 12-Apr-20 01:20 PM goddamn it 12-Apr-20 01:20 PM ebay is a very dangerous place 12-Apr-20 01:20 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-10216.png 12-Apr-20 01:29 PM nice score 12-Apr-20 01:32 PM this will be interesting 12-Apr-20 01:32 PM I wonder how they are connected 12-Apr-20 01:43 PM at least buying detectors is less bad than my recent scintillator growing research fixation that i cant quite shake lately 12-Apr-20 01:43 PM really do not need to get into that...is what i keep telling myself 12-Apr-20 01:45 PM I looked into scint growing. 12-Apr-20 01:45 PM I remember seeing somewhere that even if you can pull a boule of NaI, getting the Tl evenly disbursed in it is tough. 12-Apr-20 01:47 PM oh I've been there 12-Apr-20 01:47 PM SrI2:Eu 12-Apr-20 01:47 PM but I decided for myself that an oven for that would too big for my workshop 12-Apr-20 01:48 PM i was looking at trans-stilbene and some of the LaBr3(Ce) processes 12-Apr-20 01:48 PM I could be mistaken here, but it looked more complicated than grinding up dead NaI’s and running a Czochralski process. 12-Apr-20 01:48 PM because the stilbene is basically all able to be done indoors and not hygroscopic 12-Apr-20 01:48 PM and the LaBr3(Ce) crystals seem to have really high light yield 12-Apr-20 01:48 PM those take a lot more work 12-Apr-20 01:49 PM Not to mention the dry box needed to machine and polish them. 12-Apr-20 01:50 PM and a bridgman furnace 12-Apr-20 01:50 PM problem from what i have been reading with the stilbene crystals is that you cannot just buy off the shelf material due to some unspecified contamination (the paper didnt manage to ID it) so you have to make your own 12-Apr-20 01:50 PM so everything has problems 12-Apr-20 01:53 PM I’ve been tempted to try and see if I can make a salicylate scintillator. I saw a reference in a paper to neutron detection using them 12-Apr-20 10:09 PM dang, just saw the listing for those si19n tube arrays...thats some pricey stuff! 12-Apr-20 10:09 PM glad i got my single one of those for about $50 13-Apr-20 02:09 AM Well, I asked nicely and got them for a fair bit cheaper 13-Apr-20 02:09 AM But yeah, still 13-Apr-20 02:09 AM I'm planning to sell some to get a bit of my money back 13-Apr-20 07:27 AM Dare I ask, @GigaSquirrel, what you’re planning on doing that generates neutrons? 13-Apr-20 07:27 AM same thing everyone's doing to generate neutrons ^^ 13-Apr-20 07:27 AM only that no one seems to be using the things to their full potential, most people don't even activate some metals with it 13-Apr-20 07:34 AM Oh, right. You have HPGe + lead castle can can do seriously neat activation experiments. 13-Apr-20 07:35 AM 'tho I'm kinda stuck at building diagnostics for the thing and haven't actually worked much on the source itself recently :D 13-Apr-20 07:35 AM yep ^.^ 13-Apr-20 07:35 AM loooong term goal is pgaa 13-Apr-20 07:36 AM Looking at a fusor, or AmBe? 13-Apr-20 07:36 AM fusor ^^ 13-Apr-20 07:36 AM alphaBe is basically Impossible here, there is no way to get a source like that 13-Apr-20 07:38 AM Ok, how “prompt” are we talking? Something to consider, HPGe’s get damaged by neutrons. 13-Apr-20 07:38 AM ^ 13-Apr-20 07:38 AM There’s a neutron destroyed detector somewhere on one of our shelves from that very thing 13-Apr-20 07:39 AM Prompt as in "the moment of capture" 13-Apr-20 07:39 AM lol yeah, but not at the kind of flux we're talking about here 13-Apr-20 07:39 AM Fair enough 13-Apr-20 07:40 AM I'd be lucky to reach 10^2 n/s*cm² thermal 13-Apr-20 07:40 AM That’s what I was afraid of.... as in the neutron source is going to be in proximity to the detector. 13-Apr-20 07:41 AM plus I've got a lot of shielding here 13-Apr-20 07:41 AM so yeah 13-Apr-20 07:41 AM I’ve seen instructions for “healing” neutron damage in HPGe’s by heating the crystal. 13-Apr-20 07:41 AM yep 13-Apr-20 07:41 AM but as I said, that's a non issue here 13-Apr-20 07:43 AM How do you shield neutrons? Lead alone won’t do it. I thought you need a lot of hydrogen rich material to slow them, then lead to capture them. 13-Apr-20 07:44 AM borated hpde / paraffin and then lead to swallow the resulting gammas 13-Apr-20 07:44 AM Wow, you’ve got that? 13-Apr-20 07:45 AM I've got borax and hdpe / paraffin 13-Apr-20 07:45 AM and lots of lead 13-Apr-20 07:45 AM and I mean lots 13-Apr-20 08:25 AM Just found a picture of my neutron detector. 13-Apr-20 08:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-29CA4.jpg 13-Apr-20 09:25 AM This reminded me.... I’ve been geeking out about the ADM-300 “smart” survey meters. 13-Apr-20 09:25 AM I acquired an attachment to one, and it’s confusing me. 13-Apr-20 09:25 AM It’s supposedly an alpha/beta probe. 13-Apr-20 09:25 AM It’s clearly constructed like an alpha scint. 13-Apr-20 09:25 AM The nice things about the ADM-300 is that they are military surplus and used units come up for sale frequently. 13-Apr-20 09:25 AM Probes, on the other hand, are largely unobtainium at anything resembling reasonable prices. 13-Apr-20 09:25 AM I had been hoping to reverse engineer this so people could build and attach their own probes to the unit. 13-Apr-20 09:25 AM That said, I’ve been able to get a few probes. 13-Apr-20 09:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-BD7CB.jpg 13-Apr-20 09:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-87DDA.jpg 13-Apr-20 09:25 AM I’ve taken it apart. It’s just a PMT inside. 13-Apr-20 09:25 AM What confuses me: it is definitely alpha sensitive. 13-Apr-20 09:25 AM But when I expose it to beta/gamma sources, it’s completely insensitive. 13-Apr-20 09:25 AM Is the scint layer supposed to be sensitive to alpha and beta, and in which case why isn’t it? 13-Apr-20 09:25 AM Is something inside missing? 13-Apr-20 10:10 AM alpha / beta probes are usually ZnS for alpha deposited on some Beta sensitive plastic scintillator sheet 13-Apr-20 10:10 AM are you sure your trigger is set correctly? The beta signals will be an order of magnitude or more smaller than the alpha signals 13-Apr-20 10:17 AM I don’t know. 13-Apr-20 10:17 AM This is supposed to be plug and play with a digital survey meter. 13-Apr-20 10:17 AM I figure one of two things might be happening, now that you say this: 13-Apr-20 10:17 AM A. It’s supposed to be reporting alpha + beta but the threshold is too high. I’m not sure how this would be set, e.g. a pot in the unit itself, or if it is software configurable via the smart meter. 13-Apr-20 10:17 AM B. This thing really has a dual channel analyzer. The smart meter is supposed to tell the probe whether it should return counts of alpha, beta, or both. It’s defaulting to alpha only. And either I don’t know how to change the smart meter, or the smart meter has firmware that doesn’t recognize this probe and defaults to alpha only. 13-Apr-20 10:26 AM I'd open it up and look for obvious pots / hints 13-Apr-20 10:28 AM I did, but now that I know what to look for, that might give me a better idea.... 13-Apr-20 10:28 AM I also reached out to Mirion tech support, seeing as they bought Canberra, asking for info / manuals. 13-Apr-20 10:28 AM I have a manual for the base ADM-300 that covers most of the probes I have. 13-Apr-20 10:30 AM I've had gread success with getting circuit diagramms from canberra 13-Apr-20 10:37 AM The AP-100 (a typical alpha scint) The BP-100 (a G-M pancake) that is broken The XP-100 (a CaF2(Eu) scint) 13-Apr-20 10:37 AM But nothing for the ABP-100.... 13-Apr-20 10:37 AM The Air Force used this extensively. The XP-100 was specifically for detecting Pu-239 from broken arrow incidents. 13-Apr-20 10:39 AM CaF2:Eu O.o 13-Apr-20 10:39 AM why :D 13-Apr-20 10:42 AM From the movie: 13-Apr-20 10:42 AM (Frank Whaley) "A Broken what?" (Secretary Baird) "Broken Arrow. It's a Class 4 Strategic Theatre Emergency. It's what we call it when we lose a nuclear weapon." (Frank Whaley) "I don't know what's scarier, losing nuclear weapons, or that it happens so often there's actually a term for it." 13-Apr-20 10:46 AM :D 13-Apr-20 11:01 AM I’ve been trying to reverse engineer these off and on. 13-Apr-20 11:11 AM The BP-100 has a serial EEPROM that presumably has the probe type coded in it, and calibration data (if any; I have reason to suspect the BP-100 doesn’t have any, whereas others like the alpha probe can be calibrated for efficiency.) I’ve tried clipping a logic analyzer on it and hand decoding, and I’m seeing truly anomalous data. The ADM-300 “brain” appears to be reading the same address multiple times and getting a different result. There are no writes in the trace, so nothing is changing it. 13-Apr-20 03:09 PM @Addison-110m Again, sigh, this is what I get for a weekend with the computer off. No, I appear to have missed someone doing very silly things with Po-210. I do recall someone with more money & free time than sense learning that anti-static guns had a radioactive element and they went and harvested dozens of junked guns, not realizing that the reason they were junked is that the Po-210 had looooong since decayed away. 13-Apr-20 08:05 PM Ah I have an ADM-300 with the AP-100 and BP-100 probes as well 13-Apr-20 08:05 PM Unfortunately don't have access to it due to the lockdown 13-Apr-20 08:05 PM I think my BP-100 is working, so might take off the back cover to compare my probe with yours @rdpierce 13-Apr-20 08:05 PM That will have to probably wait for a month or two though 13-Apr-20 08:57 PM Thanks @Mason_Yu. 13-Apr-20 08:57 PM I'd appreciate any help with this. 13-Apr-20 08:57 PM Canberra came to the rescue. Their tech support got me documentation for the ABP-100 probe, and I think I see what happened. 13-Apr-20 08:57 PM These smart probes use a 7 pin connector. This provides +5V power, ground (each probe has its own HV bias supply suitable for whatever type it is), a pulse line that the ADM-300 counts, and a way to read (and probably write) the serial EEPROM. I believe the ADM-300 learns the probe type from the EEPROM, and then reads probe-specific calibration parameters, if any. 13-Apr-20 08:57 PM (I believe the alpha probe has conversion factors to account for efficiency so it can directly report source activity per 100 cm^2.) 13-Apr-20 09:02 PM So every "smart" probe must have an EEPROM then 13-Apr-20 09:02 PM Yes, they all do. 13-Apr-20 09:02 PM But here's the kicker - the ABP-100 uses TWO pins for outputting events. One is alpha only. One is alpha + beta. 13-Apr-20 09:02 PM And my ADM-300 only recognizes it as an alpha probe. 13-Apr-20 09:02 PM I think this is a firmware version issue. My ADM-300 firmware doesn't know about the existence of te ABP-100, is treating it as a normal AP-100, and is only counting the alpha only channel. 13-Apr-20 09:02 PM It should give me an option to select betwen alpha vs. beta measurement. 13-Apr-20 09:04 PM Hook your scope up to the pulse output lines without the ADM-300 and see if you can see the beta pulses? 13-Apr-20 09:05 PM And, presumably, selectively count on one channel or the other. (I'm not sure if it provides alpha + beta, or if it uses anti-coincidence to get beta only.) 13-Apr-20 09:05 PM Yeah, I plan to scope this out. 13-Apr-20 09:08 PM So do you get any pulses at all with your BP-100 probe? Does the ADM-100 recognize it's connected to an external probe when you plug it in? 13-Apr-20 09:09 PM I've also dumped the EPROM's for both versions of the ADM-300 firmware. Now I know what the unit should say on its screen, I could look at the text strings in the hex dump to see if it is supported. 13-Apr-20 09:09 PM This may tell me if I have firmware that's too old. 13-Apr-20 09:09 PM With my BP-100, the ADM-300 recognizes that the beta probe is connected but I'm seeing zero pulses. 13-Apr-20 09:09 PM I thought I heard the whine of the HV bias supply in it, and I though I used a high-impedance probe to determine that the G-M tube had bias, but I didn't troubleshoot the signal path further. 13-Apr-20 09:09 PM I did clip a logic analyzer to the serial EEPROM to try to see what data addresses and values were read, and based on my reading of the chip datasheet, it read the same two addresses multiple times and got different results for each. I don't understand that. 13-Apr-20 09:22 PM I believe the EEPROMs are 93C46 13-Apr-20 09:22 PM A friend took apart his BP-100. Here are pics: 13-Apr-20 09:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20180421_181207764_LL-5B64C.jpg 13-Apr-20 09:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20180421_181107090_LL-9498E.jpg 13-Apr-20 09:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20180421_181049471_LL-6AEAA.jpg 13-Apr-20 09:29 PM time to get the eprom programmer out 13-Apr-20 09:44 PM I already dumped the EPROM's in the ADM-300. The serial EEPROMs in the probe are another question.... My plan is to trace how they are wired to the connector, and then I can probably read them via Arduino. 13-Apr-20 09:44 PM I see a quad 3-state buffer in there, so there may be pins multiplexed. 13-Apr-20 09:44 PM But I'm also going to want to revisit whether I understand the EEPROM, and why my decode (by hand) showed the same address being read and returning different results. 14-Apr-20 01:03 PM http://twitter.com/nuclearkatie/status/1249917284098981894 14-Apr-20 01:06 PM That source is from the 1960s. At this point, it’s probably <2 Ci. At 1 m, 2 Ci of Co-60 is 2.6 R/h. Not great, not terrible. 14-Apr-20 01:17 PM I did a thing! 14-Apr-20 01:17 PM since I will be getting 10 neutron detectors soon ™️ but have nothing to read 10 detectors I built a 10-to-1 summing amplifier 14-Apr-20 01:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-29727.png 14-Apr-20 01:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3EB1F.png 14-Apr-20 01:17 PM built from stuff I had laying around, is powered by the preamp supply 14-Apr-20 02:06 PM For reference, as I've been answering questions about that particular DROP & RUN source for 6 years now, 2Ci of Co-60 is attention getting as a lost source. You'd need to post an area 23m in radius as a Radiation Area (read: the area that is in excess of .05mGy/hr). You'd have to exclude public access to out to a 32m radius. The 5cm dose rate, which we normally would call the extremity dose rate, is .17Gy/min. The contact dose rate is ~5Gy/min which will give skin burns if you hold it for more than a minute or two while swiftly putting it in a shielded vessel. 14-Apr-20 02:14 PM Decidedly less lethal than it was on July 1st, 1963, but there is a reason lost radiography source incidents keep making the news. 14-Apr-20 02:14 PM I’m definitely not volunteering to pick it up with my bare hand, and I’m certainly not denying that it is a hazard. I’m just saying Katie’s you’ll-die-with-5-mins-dose calculation is based on the source’s original activity, which is more than three orders of magnitude greater than its current activity. 14-Apr-20 02:23 PM I’ve got it.... that source’s activity at 1m is 0.72 Dyatlovs, where 1 Dyatlov is defined as 3.6 R/h. 15-Apr-20 07:22 PM Well, today was productive. I was able to do a lot more reverse engineering on the ADM-300A Geiger counters. 15-Apr-20 07:22 PM My university studies in EE are paying off. Last time, I just saw Quad NAND Gate and skimmed over the "Open Drain" part. Now, having taken a digital logic design class, I realized that they're using the NAND gates as drivers, along with 3-state buffers, to multiplex the lines to serve multiple purposes. One "mode" is used normally, the other is used when reading the EEPROM. 15-Apr-20 07:22 PM Also, I am suspecting a bad G-M pancake, or bad connection to the pancake, in the probe. When I used a 1 GOhm probe to measure the voltage, I was seeing about 400V, and the base unit registered a whole bunch of events once the probe's impedance changed the HV. So there's definitely HV bias, and a working path for signal to get processed into digital pulses and sent from the probe into the "brains". 15-Apr-20 07:22 PM I also think I may be able to hack an Arduino to read the EEPROM in the "smart" probes. 16-Apr-20 01:44 PM https://arxiv.org/pdf/1509.02379.pdf 16-Apr-20 02:18 PM that's delightful :D 16-Apr-20 02:18 PM that low energy resolution response is impressive 16-Apr-20 02:18 PM are all gas proportional detectors that responsive down in the tens-of-keV-and-below range? 16-Apr-20 02:21 PM yep 16-Apr-20 02:21 PM assuming window and stuff 16-Apr-20 02:21 PM https://www.govinfo.gov/content/pkg/GOVPUB-C13-e1dc760c61953d546b82b1cfed597f4b/pdf/GOVPUB-C13-e1dc760c61953d546b82b1cfed597f4b.pdf I have no idea what that thing actually is, but there's some wonderful glassworking in there 16-Apr-20 02:25 PM ultrasonic quartz milling.. good gosh 16-Apr-20 04:57 PM Daaaaaaaaaang 17-Apr-20 03:51 PM I’ve made some progress.... 17-Apr-20 03:51 PM My broken BP-100 probe for the ADM-300A has a dead pancake tube. 17-Apr-20 03:52 PM f 17-Apr-20 03:52 PM wait this isn't your progress is it 17-Apr-20 03:53 PM I’m trying to troubleshoot a dead on arrival eBay probe to find out why it’s dead. 17-Apr-20 03:53 PM So I desoldered the pancake tube, tested it, and it’s dead. 17-Apr-20 03:53 PM The HV bias tests out OK at 777 V according to my 1 GOhm voltage divider probe. 17-Apr-20 03:53 PM I think I see a pinhole in it. 17-Apr-20 03:53 PM I also connected a Russian SI-22G I had on hand to the probe’s circuit board. That’s a bit above normal operating voltage, but not enough to cause it to break down. 17-Apr-20 03:53 PM It started working. So I think the electronics are fine, I just need a new pancake. 17-Apr-20 03:58 PM yay! 17-Apr-20 03:58 PM I’m going to check with Canberra / Mirion and ask for specs on it, and hope they will tell me. 17-Apr-20 03:58 PM is there no marking on the pancake? 17-Apr-20 03:58 PM But if not, does anyone recognize this? 17-Apr-20 03:58 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-34C44.jpg 17-Apr-20 03:58 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-896C3.jpg 17-Apr-20 03:59 PM yep 17-Apr-20 03:59 PM one sec 17-Apr-20 03:59 PM https://www.ebay.com/itm/232212333242 17-Apr-20 03:59 PM that would be the original replacement 17-Apr-20 03:59 PM but I'm 99% sure it's a lnd 7317, check the size with yours 17-Apr-20 03:59 PM and yeah, that tube is 200% dead, it should not have any wrinkles and be slightly concave 17-Apr-20 04:01 PM I thought so.... The window makes a crinkly sound when I pick up and move the tube. 17-Apr-20 04:02 PM shudders 17-Apr-20 04:02 PM If it were under partial vacuum, I’d think it should be immobile. 17-Apr-20 04:02 PM oh absolutely 17-Apr-20 04:07 PM Ok how is the cathode lead connected? 17-Apr-20 04:07 PM case is the cathode, looks like in your case it's soldered? 17-Apr-20 04:08 PM The weird thing about this probe is that the anode is at +HV and the cathode is at -HV. The whole case may be insulated. 17-Apr-20 04:09 PM wait what 17-Apr-20 04:09 PM symmetrical hv?! 17-Apr-20 04:10 PM Yeah. 17-Apr-20 04:10 PM I was surprised. 17-Apr-20 04:10 PM It’s not exactly symmetrical, I measured anode +387V cathode -423V although those aren’t simultaneous measurements and I’m probably shifting the values related to ground by measuring them. Anode to cathode is 777 V. 17-Apr-20 04:10 PM How do you solder to the case without something to mechanically bond the wire to? The case would act as one giant heat sink. Sounds like a recipe for a cold joint. 17-Apr-20 04:16 PM a cold joint and / or broken mica 17-Apr-20 04:16 PM i have no idea tbh 17-Apr-20 04:16 PM 'tho since the wire isn't moved in respect to the tube I think a piece of copper tape should also do the job 17-Apr-20 04:26 PM There's also conductive epoxy 17-Apr-20 04:26 PM https://www.mgchemicals.com/products/adhesives/electrically-conductive-adhesives/two-part-epoxy/silver-conductive-epoxy-8331 17-Apr-20 05:05 PM depends on what the case is made of... some materials don't actually conduct heat well so an iron (if high enough wattage/effecient enough) can heat a small area on the surface quickly and hot enough to solder well... 17-Apr-20 05:05 PM for example nickel tabs on batteries... 17-Apr-20 05:05 PM they don't transfer heat too quickly so they generally solder well 17-Apr-20 05:44 PM if you need to solder something to a large heat sinking surface those giant weller pistol grip soldering guns are amazing...but i am not sure how well that would go on a pancake tube 17-Apr-20 07:58 PM Looks like the russian tunnel diode fixed the old 70s Ludlum Model 12! \o/ 17-Apr-20 07:58 PM its clicking again, or at-least well... the clicks and squeals this thing makes 17-Apr-20 07:58 PM https://www.ebay.com/itm/Switching-Tunnel-Diode-AI301A-3I301A-Ga-As-military-USSR-Lot-of-10-pcs/142804191525 17-Apr-20 07:58 PM these are what I got for reference 17-Apr-20 07:58 PM I dunno if its perfect... it may have effected the integration into the caps for the readout... so it may need to be adjusted but it has a weird scale on mine anyway so I really need to adjust it to whatever scale I want anyway... so not a big deal 17-Apr-20 07:58 PM better than a resistor being there in place anyway :) 17-Apr-20 08:15 PM And that was fascinating,... my dead BP-100 had HV set to 777 V. That seems... weird. Too high for the 400-500V probes, too low for the 900V probes. 17-Apr-20 08:15 PM I hit the jackpot - someone online had a factory calibration manual, 17-Apr-20 08:15 PM That voltage wasn’t given, but voltage at a test point (which is approx. the inverse of the cathode voltage) was.... 17-Apr-20 08:15 PM It was 422 V. 17-Apr-20 08:15 PM It should be 250 V. 17-Apr-20 08:15 PM When I turned down the trim pot until it was 250 V, the anode to cathode voltage went down to 464 V. So someone must have cranked on that trim pot until it was >300V too much. Whiskey Tango Foxtrot??? 17-Apr-20 08:23 PM as the rule is with anything old you get 17-Apr-20 08:23 PM never assume anything is setup correctly 17-Apr-20 08:23 PM whether it be jumpers or trim pots... 18-Apr-20 07:07 AM So I’m trying to make this ADM-300A and BP-100 probe give up all its secrets. 18-Apr-20 07:07 AM I’ve already traced out the digital interface on the probe that connects to the survey meter. 18-Apr-20 07:07 AM However, the analog side of things seems to be largely contained inside a big box of metal with IC pins. 18-Apr-20 07:07 AM It’s called a “hybrid IC” and its part is NRC 602088-001 18-Apr-20 07:14 AM oh boi 18-Apr-20 07:14 AM I’m assuming the datasheet for this is lost to the ages, as it seems very proprietary to NRC (and its successor, Canberra) Geiger counters. 18-Apr-20 07:14 AM I may or may not have gotten the first neutrons out of my fusor! 18-Apr-20 07:15 AM Oh congrats!!!!!!!!!!!!!!!!!!!!!! 18-Apr-20 07:15 AM Thanks ❤️ 18-Apr-20 07:15 AM funny thing is 18-Apr-20 07:15 AM I could never get the "classical" grid to work properly 18-Apr-20 07:15 AM burns way to unstable 18-Apr-20 07:15 AM so I tried the "doug coulter style" cylindrical grid, and it works so well! 18-Apr-20 07:22 AM So what I can figure out: 2 digital lines go into this NRC hybrid IC, and one comes out. 18-Apr-20 07:22 AM Now things get weird. 18-Apr-20 07:22 AM One input to the chip might be a line to turn the HV on or off, or maybe the output. It seems to be low shortly after the EEPROM gets read, then goes high afterwards, presumably when the probe is ready to operate. 18-Apr-20 07:22 AM The output line is normally high and gets pulled low for around 11 us. This seems clear that it is how the probe signals to the survey meter that an event happened. 18-Apr-20 07:22 AM But the second input to the chip is... weird. 18-Apr-20 07:22 AM I call it the Midsommar line. 18-Apr-20 07:22 AM Kind of like where one woman cries, and all the rest of the women in the village cry with her, and it’s really creepy. 18-Apr-20 07:22 AM After each 11 us event, there’s a variable time delay, then a much longer 1.5 to 2.5 ms pulse, 18-Apr-20 07:22 AM So this seems like it is software controlled. 18-Apr-20 07:22 AM Also, sometimes the survey meter sends such a pulse to the probe without a prior signal from the probe to the meter. 18-Apr-20 07:22 AM When there aren’t events, it seemed like a regular 2 second cycle of a pulse. 18-Apr-20 07:22 AM I do know that the ADM-300A is a little unusual in that it uses a time to count statistical algorithm, allegedly to correct for dead time and coincidence. 18-Apr-20 07:22 AM So this might be some kind of inhibit? The survey meter doesn’t have to count every pulse. But I’m not sure why the survey meter software echoes the pulses received back at the probe, stretched by a factor of 10-25, Midsommar style. 18-Apr-20 07:22 AM Any thoughts? 18-Apr-20 11:11 AM Can someone explain radiation "annealing" after electronic radiation testing? I always assumed that cumulative radiation damage on IC (ie not single event upsets) where basically due to displacement. So how does waiting up bit potentially fix it? 18-Apr-20 11:15 AM Doesn't that generally involve heating the IC/component up and annealing it to lower the impact of the radiation exposure to that point? 18-Apr-20 11:17 AM Yeah so for space hardware you typically run in in front of a Co-60 source for a while (say up to 30 kRad) and then anneal at high temp 18-Apr-20 11:17 AM From what I have been told the idea is that the Co sources have too much flux so you get up to dose too fast 18-Apr-20 11:17 AM What I don't understand is how annealing fixes anything 18-Apr-20 11:20 AM I think it just gets the physical structure to normalize the damage (to a certain extent) which restores some of the original functioning/characteristics 18-Apr-20 11:20 AM "Annealing occurs by the diffusion of atoms within a solid material, so that the material progresses towards its equilibrium state. Heat increases the rate of diffusion by providing the energy needed to break bonds. The movement of atoms has the effect of redistributing and eradicating the dislocations in metals and (to a lesser extent) in ceramics." 18-Apr-20 11:20 AM That is just from wikipedia but I think it explains the mechanism, as I understand it, fairly well 18-Apr-20 11:20 AM https://en.wikipedia.org/wiki/Annealing_(metallurgy) 18-Apr-20 11:24 AM Ok so basically radiation damage will displace atoms and annealing bring them back to their place. Since in real life your electronics doesn't get 30 krad in a week this is used to speed up the normal thing that would happen over a few years. 18-Apr-20 11:25 AM That is my understanding of it 18-Apr-20 11:28 AM Our EE have so much trouble diagnosing this. With components working intermittently and all kind of crazyness. Seems like black magic to me. 18-Apr-20 11:28 AM You got me curious and this seems like it has a more in depth discussion of the exact mechanisms involved broken down by radiation type: https://www.osti.gov/servlets/purl/10181318 18-Apr-20 11:28 AM Also @Dyno doesn't like the f word apparently 18-Apr-20 11:28 AM oh thanks! The whole radiation thing is still a big black box for me 18-Apr-20 02:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8170A.png 18-Apr-20 02:26 PM a reacting reactor! 18-Apr-20 03:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/S2230002-37856.JPG 18-Apr-20 03:40 PM I installed halogen bulb (freed from its glass) in there, acts as a nice chamber light and as hot cathode for a quick ion source 18-Apr-20 03:50 PM are you gonna bake with UV light? 18-Apr-20 03:51 PM heh 18-Apr-20 03:51 PM no baking yet 18-Apr-20 03:53 PM Well when you do, don't forget to add salt for flavor 18-Apr-20 03:53 PM Otherwise it might be a tad bland :P 19-Apr-20 05:15 AM man am I glad about the amount of lead I've collected here 19-Apr-20 05:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6C6A2.png 19-Apr-20 06:33 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200419_151241-6031E.jpg 19-Apr-20 06:33 AM it's time for tungsten! 19-Apr-20 08:18 AM @GigaSquirrel that’s not the right pancake. T2000/8767 is a 900V tube. The BP-100 is a 500V probe. 19-Apr-20 08:19 AM oh, hm 19-Apr-20 08:19 AM in that case maybe go through the lnd website and sort by voltage? 19-Apr-20 08:20 AM 7317? 19-Apr-20 08:21 AM that's 900V, that's the one I suggested 19-Apr-20 08:21 AM I think that’s the 500V one, the 7311 is the 900V 19-Apr-20 08:21 AM And wow, that's one heck of a field you've got there 19-Apr-20 08:22 AM oh, you're right! 19-Apr-20 08:22 AM I must have mixed them up, the 7317 is 500 volts indeed 19-Apr-20 08:29 AM https://mirion.s3.amazonaws.com/cms4_mirion/files/pdf/spec-sheets/c49256_gm_tubes_spec_sheet.pdf?1586451254 19-Apr-20 08:29 AM They claim they make the tubes in Oak Ridge. 19-Apr-20 08:29 AM Is that right? Or are they rebranding LND tubes? 19-Apr-20 10:27 AM no idea tbh 19-Apr-20 10:27 AM I always assumed they rebrand, but I can't find anything from lnd related to oak ridge 19-Apr-20 10:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200419_191419-5EE4A.jpg 19-Apr-20 10:27 AM makes a nice desk toy :D 19-Apr-20 10:36 AM Grid melted? 19-Apr-20 10:37 AM yep 19-Apr-20 10:37 AM What was it made from? 19-Apr-20 10:37 AM stainless 19-Apr-20 10:38 AM What’s the pitting on the top part? 19-Apr-20 10:38 AM And wow 19-Apr-20 10:39 AM Looks like you got sputtering on the top? 19-Apr-20 10:41 AM went a bit overboard with the acids I used to remove flux after brazing 19-Apr-20 03:48 PM Could i safely point an open microwave oven at the ground while running? 19-Apr-20 03:48 PM Point being to kill plants and hopefully their roots 19-Apr-20 03:48 PM Also, i think I'd be fine if a small wheeled robot had to do it 19-Apr-20 03:48 PM It might take a while anyway 19-Apr-20 03:48 PM Or is there a safer feedhorn design? 19-Apr-20 03:50 PM You’d need a waveguide/feed horn 19-Apr-20 03:50 PM But it certainly can be done 19-Apr-20 03:51 PM that seems like something where it is also worth looking into the legal side of things before trying it lest you make new friends with fancy job titles 19-Apr-20 03:51 PM not really a safety point I guess 19-Apr-20 03:56 PM they're strongly correlated 19-Apr-20 04:26 PM Yeah if it's not radiating outward anywhere away from the ground, I doubt anyone cares 19-Apr-20 04:29 PM I can’t imagine the FCC would notice if there’s no interference 19-Apr-20 04:29 PM Worst case scenario, get a ham license 19-Apr-20 05:00 PM https://www.youtube.com/watch?v=aa7bK-N1Pps 19-Apr-20 05:00 PM https://www.eng.tau.ac.il/~jerby/AMPERE-Newsletter_website/Papers_PDFs/AMPERE-NL-93_09-17.pdf 19-Apr-20 05:00 PM In a review of microwave soil treatment for weed seed deactivation, Nelson (1996) estimated that the cost of microwave treatment would be about US$850 per acre (US$2,100 ha-1). He concluded that this was an unreasonable cost for weed control (Nelson 1996); however, since Nelson’s paper was written, the agricultural industry has become acutely aware of herbicide resistance and the high indirect costs of herbicide use; therefore, microwave weed management strategies are again under consideration. 19-Apr-20 05:06 PM If the microwave is held tightly to ground it should leak relatively little 2.4GHz RF 19-Apr-20 05:07 PM An experimental microwave trailer has been developed (Figure 4) to slowly move over the soil during experiments. It has four independently controlled, 2 kW microwave generators operating at 2.45 GHz. The trailer is powered from two on- board 7 kVA, 3-phase electrical generators. The microwave energy is channelled to the ground via waveguides and horn antennae. The trailer can be used to treat emerged weeds and grasses. For example, thermal images revealed that kikuyu grass (Pennisetum clandestinum) achieved a temperature of 61 °C (Figure 5) when the trailer was moved over the grass at between 700 and 900 m hr-1. There was audible crackling of the grass as the antennae moved along the strip, indicating that micro-steam explosions were occurring in the grass stems due to rapid microwave heating. After 4 days, the treated strips were quite evident (Figure 6), with 100 % mortality along almost all the treated strips. 19-Apr-20 05:07 PM From that video 19-Apr-20 05:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200419-170743-40B64.png 19-Apr-20 05:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200419-170843-0429E.png 19-Apr-20 05:07 PM From the paper 19-Apr-20 05:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_20200419-170931-78EFD.png 19-Apr-20 05:07 PM I'm pretty interested to just bypass this microwave door I've got and pull an extension cord out 19-Apr-20 05:07 PM Plop it face down on the weeds in my yard 19-Apr-20 05:17 PM Thare's usually two safety switches in series with the mains supply 19-Apr-20 05:18 PM one switch is NO which shorts the supply to the HV portion, the other is NC which allows operation. 19-Apr-20 05:18 PM it's designed that if it doesn't turn off when opening the door a backup fires and shorts the power to the hv portion and blows fuses 19-Apr-20 05:19 PM Ah! good design 19-Apr-20 07:47 PM This sounds like something our favorite Ukrainians did.... 19-Apr-20 07:59 PM https://youtu.be/tQ1185dRuPU 19-Apr-20 07:59 PM Massive stupidity. 19-Apr-20 08:02 PM I'm still waiting for the big xray tube 21-Apr-20 12:06 PM so these things have been on ebay for many many months https://www.ebay.com/itm/MDC-High-Vacuum-4-5-ConFlat-CF-Water-Cooled-Synchrotron-Light-Beam-Shutter/222751321952 21-Apr-20 12:06 PM i don't really have a use for one (but i kinda want one), but ... what's the chance that these are LLRW? that definitely looks like a well-used beam stop 21-Apr-20 12:08 PM good point 21-Apr-20 12:08 PM 'tho it might have actually been light, visible or soft x-ray 21-Apr-20 12:09 PM ya true 21-Apr-20 12:10 PM buy one and measure it 21-Apr-20 12:10 PM now I want to know 21-Apr-20 12:11 PM maybe if i can figure out a proper disposal plan if it turns out there's anything to measure >_> 21-Apr-20 12:12 PM just forward it to @funranium 21-Apr-20 12:12 PM if it was a gate valve i'd be all over it, but i don't think i have any use for a shutter besides like.. idk, very slow shutter for a lock-in experiment or smth 21-Apr-20 12:43 PM @GigaSquirrel hey so, get any n/s numbers out of your fusor yet? 21-Apr-20 12:44 PM nope 21-Apr-20 12:44 PM my "calibrated" detector is not working with my current setup, gotta fix that soon-ish 21-Apr-20 12:44 PM and at the moment it's down for upgrades anyways, as my grid decided to melt ^^ 21-Apr-20 12:49 PM oops 21-Apr-20 12:50 PM new version will be tungsten 21-Apr-20 12:50 PM do any measurements of induced radioactivity on the grid afterwards? i know plasma focus pinches are spritely enough to implant 3He in the anode, and have been wondering about fusor-shaped things since 21-Apr-20 12:50 PM I held a contamination monitor up to the grid, but that was about it 21-Apr-20 12:50 PM it had a total run time of like 5 minutes tops 21-Apr-20 12:51 PM nodnod 21-Apr-20 12:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200421_214959-02171.jpg 21-Apr-20 12:51 PM and now it's decoration 21-Apr-20 12:51 PM nice :D 21-Apr-20 12:52 PM I was thinking about using thoriated tungsten here 21-Apr-20 12:52 PM but I don't really want to machine it 21-Apr-20 12:52 PM and / or sputter that in my chamber 21-Apr-20 12:52 PM but I'd be surprised if I had more than e4, maaaaybe e5 output 21-Apr-20 01:15 PM searching around for some of the modules listed in #swap-meet, encountered this old report full of methods for doing biological assays for environmental radioactive contaminants (Sr90, Cs137, Pu242) https://books.google.com/books?id=m2QhCUVFlT8C&pg=PA12&lpg=PA12&dq=ortec+433&source=bl&ots=vhjmr8LmFR&sig=ACfU3U3t23U4JdjuGlef-6xrfxQnGeY2AA&hl=en&sa=X&ved=2ahUKEwjl9tXlqProAhUvJTQIHU8aCrwQ6AEwBHoECAoQAQ#v=onepage&q=ortec%20433&f=false 21-Apr-20 01:15 PM can't wait for the 'Extracting Plutonium From SUSHI!?' youtube video to show up 21-Apr-20 01:19 PM 48% HF though, oof 21-Apr-20 01:22 PM just the tee part of those shutters is pretty cool 21-Apr-20 01:22 PM small CF tee with built-in bellows 21-Apr-20 01:51 PM http://www.nuclearphysicslab.com/npl/npl-home/experiments/gamma-gamma-coincidence/ This is a pretty nice writeup of coincidence detection 21-Apr-20 01:52 PM oh, yeah, that is a good writeup 21-Apr-20 01:52 PM so things like constant fraction discriminators or otherwise explicitly-made-for-timing SCAs are useful because non-timing SCAs will 'walk' in time based on pulse heights 21-Apr-20 01:52 PM characterizing the transit time and jitter of everything in your signal path is important.. if you're using PMT scintillators, a fast anode output (you could theoretically make or add your own in to an existing base if you're feeling thrifty) will be necessary for your time signal, and your post-dynode amplified signal will give you meaningful pulse height 21-Apr-20 01:52 PM i can dial back some of my wishlist if you're also earnestly looking to do coincidence measurements @rdpierce 21-Apr-20 02:05 PM wait actually maybe i'm mistaken about how the PMT signal is extracted in this case 21-Apr-20 02:05 PM but, yeah 21-Apr-20 02:05 PM things like the voltage divider ratio used in your PMT base will affect timing parameters somewhat also 21-Apr-20 02:05 PM and iirc PMTs with convex faces (which are annoying to couple flat-faced scintillators to) have better timing properties 21-Apr-20 02:14 PM yeah, here's a good pile of info on (photonis) PMTs in general, but i found the timing-specific stuff really informative 21-Apr-20 02:14 PM https://psec.uchicago.edu/library/photomultipliers/Photonis_PMT_basics.pdf 21-Apr-20 02:29 PM ^ also a good writeup 21-Apr-20 02:31 PM Oh and @qualia , thanks for sharing that book, stuff like that’s one of my bigger interests. 21-Apr-20 02:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200421_233102-72531.jpg 21-Apr-20 02:31 PM insert corona joke here 21-Apr-20 02:33 PM something something curve flattening 21-Apr-20 02:33 PM which amp(s) is that through? 21-Apr-20 02:33 PM @Addison-110m like, environmental contamination assays? 21-Apr-20 02:36 PM Yeah 21-Apr-20 02:37 PM cool, noted 21-Apr-20 02:37 PM i've always wanted to try and measure rain washout but i've never quite figured out the right way to do so 21-Apr-20 02:37 PM also it rains so infrequently in california that it's hard to have a lot of opportunities outside of winter 21-Apr-20 02:39 PM I did it in a really basic manner with snow a few years ago. 21-Apr-20 02:39 PM But yeah, that’s one I’ve been toying with too. That and cesium and lead in soil core samples 21-Apr-20 02:41 PM which amp(s) is that through? @qualia assuming that question was for me, that's my canberra 806 21-Apr-20 02:41 PM good luck finding any info on that 21-Apr-20 02:41 PM canberra hardware is impossible to google for lmfao 21-Apr-20 02:41 PM esp. that one 21-Apr-20 02:41 PM everything turns up australian zip codes 21-Apr-20 02:42 PM XD 21-Apr-20 02:42 PM it's just a csa, nothing special 21-Apr-20 02:42 PM but I had to get my corona He3 detector, because I didn't have the proportional one when I did the efficiency cal 21-Apr-20 02:42 PM so now I can use that as a transfer standard to measure flux from my reactor 21-Apr-20 02:43 PM heh 21-Apr-20 02:43 PM compared to the AmBe spectrum, but eh, close enough 21-Apr-20 02:44 PM does proportional mode offer any benefits over corona mode? do you get better γ discrimination in proportional mode? 21-Apr-20 02:44 PM oh no gamma disc is way better in corona 21-Apr-20 02:44 PM but corona detectors have a very short rated lifetime, 5000 h 21-Apr-20 02:45 PM ahh 21-Apr-20 02:45 PM I actually recently found something on gamma rejection 21-Apr-20 02:45 PM one sec 21-Apr-20 02:45 PM pulse height spectra of a corona He3 tube with background gamma, 360 r/h and 1740 r/h 21-Apr-20 02:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-56CA7.png 21-Apr-20 02:46 PM oh, did your weird neutron detector array show up yet? 21-Apr-20 02:47 PM same thing but proportional 21-Apr-20 02:47 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7B263.png 21-Apr-20 02:47 PM oh wow 21-Apr-20 02:47 PM nope, it's somewhere between ukraine and germany 21-Apr-20 02:47 PM https://inis.iaea.org/collection/NCLCollectionStore/_Public/29/017/29017699.pdf If you want to read further 21-Apr-20 02:47 PM and learn some russian 21-Apr-20 02:47 PM but there's actually very little information out there about corona counters 21-Apr-20 02:48 PM seems appropriate, ~all my neutron detectors are russian 21-Apr-20 02:50 PM feels like a corona detector is used a bit like a geiger müller tube, doesn't give any meaningful spectroscopic data, but is very voltage-insensitive (as in you don't need a spectroscopic bias supply) and easy to read out 21-Apr-20 02:50 PM oh and I found a manufacturer producing corona alpha detectors 21-Apr-20 02:50 PM https://consensus-group.ru/radiation-counters/alpha-radiation/113-counter-si9am-1 Kinda funny imo 21-Apr-20 02:52 PM huh, neat 21-Apr-20 02:52 PM wonder how that efficiency % compares to other detectors 21-Apr-20 02:53 PM yeah that's always a bit of a guess 21-Apr-20 02:53 PM totally hasn't gotten any work done today 21-Apr-20 02:53 PM but I suppose it should be the same, as they all have mica windows and gas behind them 21-Apr-20 02:53 PM but is the efficiency quoted in 2pi, 4pi, absolute efficiency, ...? 21-Apr-20 02:55 PM shrug.avi 21-Apr-20 02:55 PM yep 21-Apr-20 02:56 PM mm, it's getting hot out finally 21-Apr-20 02:56 PM means all my stupid paraffin is going to start running/slumping over again 21-Apr-20 02:56 PM might be time to rig up that overextruded vase-mode 3d print to finally melt it all into 21-Apr-20 02:56 PM grumble grumble hdpe is expensive 21-Apr-20 02:57 PM oh wait you're using your moderator "open", without a housing or sth? 21-Apr-20 02:57 PM naw, my 3He tube used to be semi-permanently encased in it 21-Apr-20 02:58 PM oh 21-Apr-20 02:58 PM sorry if that's a dumb question, but why? 21-Apr-20 02:58 PM like what's the advantage 21-Apr-20 02:58 PM i wrapped the tube in wax paper and then poured wax in around it, and for some reason i thought this would let it slip out afterwards, but it contracted on cooling and stuck in there until a 42C day hit and I was able to slip it out again 21-Apr-20 02:58 PM haven't done anything with it since, just have a bunch of wax sitting around to eventually melt into a more, uh, versatile casing 21-Apr-20 02:59 PM go to your local hardware store and buy two pvc tubes, one that comfortably fits your detector and one that fits around that tube with a ~5 cm gap 21-Apr-20 02:59 PM print two endcaps that hold these tubes in a coaxial arrangement 21-Apr-20 02:59 PM fill the space with paraffin ^^ 21-Apr-20 03:01 PM i wanted to avoid introducing chlorine into the mix tbh 21-Apr-20 03:02 PM hm, why's that? iirc I looked that up and the capture cross section wasn't too big 21-Apr-20 03:02 PM ABS? 21-Apr-20 03:02 PM yeah, or pe / pp 21-Apr-20 03:03 PM yeah.. other unknown is like, binding agents, fire retardants, dyes/colorants. i wanted to overengineer it for minimum spurious background when i was more interested in PGAA 21-Apr-20 03:05 PM hmm, but when doing pgaa you can put your neutron detector far away ^^ 21-Apr-20 03:05 PM https://apps.dtic.mil/dtic/tr/fulltext/u2/419181.pdf 21-Apr-20 03:12 PM i gueesss 21-Apr-20 03:12 PM that would be somewhat easier 21-Apr-20 03:12 PM i did also want to 3d print a set of bonner spheres/cylinders, gather some spectra like that, and compare against nToF 21-Apr-20 03:14 PM like I totally get your wish for all the measurements, but when you're really after ultra low background even the capture lines in hydrogen will become significant 21-Apr-20 03:14 PM heh, neutron spectroscopy is still magic to me 21-Apr-20 03:14 PM either experimental experience or looooots of monte carlo 21-Apr-20 03:14 PM nToF seems deceptively simple 21-Apr-20 03:15 PM right, but that's only useful in thermal 21-Apr-20 03:15 PM (that's what got me looking for a time-to-pulse-height converter, natch) 21-Apr-20 03:15 PM heh, gotcha 21-Apr-20 03:15 PM howso? 21-Apr-20 03:16 PM that's just a guesstimation, but at some point detector timing resolution will limit the spectral resolution 21-Apr-20 03:17 PM oh, yeah 21-Apr-20 03:17 PM seems fast dense plastic scintillators get used, along with a very long beam pipe 21-Apr-20 03:17 PM a 2.45 MeV neutron has 21.6 km/s 21-Apr-20 03:17 PM ah, right, brainfart 21-Apr-20 03:17 PM I was thinking about the time it takes to moderate to thermal for detection 21-Apr-20 03:17 PM but ofc you can just detect the fast neutrons 21-Apr-20 03:19 PM yeah heh 21-Apr-20 03:21 PM for now I'll be happy detecting fast neutrons after moderation and maybe some gammas from thermal neutrons 21-Apr-20 03:21 PM I wish I could get my hands on some Be-7 and use that for efficiency calibration, then I could sniff out thermal flux with some boron solution and my hpge 21-Apr-20 03:21 PM 'cause it's exactly the same gamma, both coming from Li7* 21-Apr-20 03:29 PM looks like some folks are working on Be-7 synthesis and trapping https://marvin.byu.edu/beryllium7/publications/RevSciInstrum-81-013507.pdf 21-Apr-20 03:29 PM relatedly, vacuum arc ion sources are neat 21-Apr-20 03:31 PM heh, nice 21-Apr-20 04:40 PM ahahaha 21-Apr-20 04:40 PM speaking of monte carlo 21-Apr-20 04:40 PM https://www.youtube.com/watch?v=vtN4tkvcBMA 21-Apr-20 04:40 PM sorry if it's a bit too off topic, but it fits so well 21-Apr-20 07:50 PM Harrumph 22-Apr-20 03:38 AM Interesting! 22-Apr-20 03:38 AM I let the neutron detector run over night 22-Apr-20 03:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200422_114712-B60D7.jpg 22-Apr-20 03:38 AM ignore the clipping 22-Apr-20 03:38 AM but those three (maybe 4?) delayed neutrons are pretty interesting imo 22-Apr-20 03:38 AM I wonder if that was just coincidence or actually delayed something 22-Apr-20 05:26 AM Grid v2, now with added tungsten! 22-Apr-20 05:26 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2C845.png 22-Apr-20 11:07 AM do you have any links/details on this funky cylindrical grid design? 22-Apr-20 11:14 AM not really 22-Apr-20 11:14 AM doug coulter apparently "invented" it? 22-Apr-20 11:14 AM but most of the stuff he does goes into esoterica quickly 22-Apr-20 11:15 AM alas 22-Apr-20 11:15 AM I just found it to be a lot more stable, with it I don't even need a ballast resistor 22-Apr-20 11:16 AM is your power supply current limited? 22-Apr-20 11:17 AM he is the one who claimed to have given himself rad sickness and activated a bunch of stuff in his shop accidentally, isn't he? 22-Apr-20 11:17 AM that does sound familiar 22-Apr-20 11:17 AM I've heard that story, but not from him iirc 22-Apr-20 11:17 AM is he also the guy that does all this in a solar-powered shack somewhere in the woods? 22-Apr-20 11:18 AM yeah, my hv supply is basically a lab power supply with CC and CV 22-Apr-20 11:18 AM yeah that's the guy 22-Apr-20 11:18 AM gotta say, the idea of a minimal-power-consumption vacuum system is extremely appealing, what with PG&E's comical $0.50-per-kW/h energy costs 22-Apr-20 11:19 AM excuse me how much are you paying?! 22-Apr-20 11:19 AM always was intrigued by his stuff but was never really sure how much of it was just bluster, if he managed to come up with a strangely effective grid design maybe that explains the rest 22-Apr-20 11:20 AM my power bill averages something like $300-$500 a month, i've seen $600 when it gets to be 40C+ in summer and we have to turn the house AC on 22-Apr-20 11:20 AM california is stupid expensive 22-Apr-20 11:20 AM he has some pretty brilliant ideas and seems like a pretty nice guy, but aparently he went from idea to idea and from theory to theory and at some point drifted away a bit from "conventional science" 22-Apr-20 11:20 AM claiming he can achieve Q>1 with a fusor etc 22-Apr-20 11:20 AM Holy Sh◼️t 22-Apr-20 11:22 AM how much electronics gear is each person in your household running? 22-Apr-20 11:22 AM (also see: why i was so hyped to replace all my fluorescents with LED replacements... two of which cooked my ballasts in the dining room. the drop-in replacement ones are, apparently, awful, and direct conversion is the way to go :T) 22-Apr-20 11:22 AM most folks just have a desktop or laptop 22-Apr-20 11:22 AM some lights, washer/dryer 22-Apr-20 11:23 AM and then there's the lab 22-Apr-20 11:23 AM i am almost certainly the biggest power user in the house, though, what with the horrible poweredge 1950 in the garage, the 24-disk fileserver, and the rack full of linear power supplies in my bedroom >.> 22-Apr-20 11:23 AM yeah lol 22-Apr-20 11:23 AM i'm desperately trying to upgrade some of this stuff to newer/more power efficient gear where possible 22-Apr-20 11:24 AM the labroom, I mean the bed, erm... 22-Apr-20 11:24 AM it's just expensive and slow going 22-Apr-20 11:24 AM 24 disk fileserver you say... haha not super surprised about the power bill 22-Apr-20 11:24 AM bedroom labroom music studio whatever :D 22-Apr-20 11:24 AM I'm so glad I got a special room for my lab, that's at a comfy >25°C all around the year, even with negative temps outside 22-Apr-20 11:24 AM when i was running a couple servers at home i was surprised how much just the power cost 22-Apr-20 11:25 AM it's kinda ridiculous yeah 22-Apr-20 11:25 AM (yeah but 50 ct?!!) 22-Apr-20 11:25 AM I think I might do most of my detector setup in my bedroom, all the other possible space is basement so background 22-Apr-20 11:26 AM you'd be surprised how much potassium is in a bed 22-Apr-20 11:26 AM Pinned a message. 22-Apr-20 11:26 AM Um? 22-Apr-20 11:26 AM i'm saving this out-of-context quote for posterity 22-Apr-20 11:27 AM I might have to redact your name and share that onto the reactor slack 22-Apr-20 11:28 AM in my area in Southern California power is anywhere from like 15-45c/kWh if you are on a time of use plan... or 20-46c/kWh for the tiered rates so around 50c/kWh sounds right for some of the even higher cost of living areas 22-Apr-20 11:28 AM yeaaah 22-Apr-20 11:28 AM kills me hearing what people pay for gas elsewhere 22-Apr-20 11:29 AM we used to be on a time-of-use plan and i got everyone in the household to shift to doing laundry and cooking and etc late at night. then, uh, Something Happened.. and we got shifted to a subsidiary power company. this 1. broke my realtime smart meter monitoring (which was REALLY NICE when it worked) and 2. completely complicated my pricing schedule and probably effectively ended up costing us more 22-Apr-20 11:29 AM also VERY ANNOYING is that it's a 'Green!! Renewable!!!' plan, which means that we don't get any power from nuclear anymore 22-Apr-20 11:29 AM not that california has much, i think 22-Apr-20 11:29 AM but still 22-Apr-20 11:31 AM it made me really upset how badly they bungled San Onofre's turbine upgrade 22-Apr-20 11:31 AM used to be great fishing down there haha 22-Apr-20 11:38 AM my power bill is about $35/month lol 22-Apr-20 11:38 AM temperate weather so use no heating in the winter and no AC in summer, all LEDs, and nothing but the fridge/oven/microwave use more than 1kw. 22-Apr-20 11:38 AM I think $30/month is the "connection" fee? 22-Apr-20 01:38 PM Wow, I pay like $0.11/kWh or something, maybe 0.13 22-Apr-20 04:38 PM Going back to the previous discussion on neutron time-of-flight, the big challenge is actually just counting statistics. It's not very difficult to build a time-to-digital converter (in the thermal region up to a few keV, you only need timing bin width measured in single digit microseconds, with a flight path of a couple of meters, thus most fast scintillators will do), but taking the detector efficiency into account, counts per bin is going to be super low 22-Apr-20 04:38 PM So the solution is usually just a really big pulsed neutron source, the kind you don't want in your house 22-Apr-20 04:38 PM As long as the pulse is short enough (again on the order of microseconds), all neutrons goes through the thermalization process and the time for them to do so actually doesn't impact resolution @GigaSquirrel 22-Apr-20 04:38 PM Thermalization is done right after the neutron source, with something simple like a water tank or poly block 22-Apr-20 04:38 PM The timing of the system (and by extension the effective flight path length) can be calibrated by looking at the energy of known resonances of a material, so you'd put like a tantalum plate or something in front of your detector and look at a capture resonance where you still have some counts in the valley 22-Apr-20 04:38 PM Example transmission curve for tantalum on an experiment I just did, bin width here is ~4 microseconds, and you can see resolution is more than enough in the thermal and epithermal region 22-Apr-20 04:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5F912.png 22-Apr-20 04:38 PM But counting statistics is still not great, just due to the low number of counts 22-Apr-20 05:30 PM oh that's pretty cool 22-Apr-20 05:37 PM Optimally you'd have as fine of a bin width as possible (limited by hardware) and do post-processing on the data by selectively combining bins to provide a nicer looking graph 22-Apr-20 05:37 PM But it's not going to get rid of the uncertainty in my case, just not enough counts. This was done with a electron LINAC with a photoneutron target, 45000 shots over 30 minutes, on average 4*10^13 neutrons per second 22-Apr-20 05:37 PM 14 meter long flight path 22-Apr-20 05:49 PM whoof 22-Apr-20 05:49 PM well that puts things into perspective 22-Apr-20 05:49 PM my harebrained dense plasma focus scheme was, assuming i really nailed down the design parameters and electrical design, likely going to net around 10^7 n/shot best-case scenario 22-Apr-20 06:01 PM i also wanted to not thermalize at the source and see if i could catch the 2.45 MeV to 25 meV range altogether, but i feel like a beamline for doing that with any useful resolution would be long. i would suspect that not thermalizing would help make the best of my limited fluence, but then i have the problem of detector stopping power instead 22-Apr-20 06:02 PM Given the efficiency of fast neutron detectors and your expected neutron yield, timing resolution is the least of your concerns I think, you'd need hundreds of thousands of shots to see anything approaching a spectrum 22-Apr-20 06:02 PM Also be aware of the gamma/x-ray flash, it might blind your detector for a few precious microseconds, and that's critical for high energy stuff 22-Apr-20 06:02 PM This is quite significant for the DPF as well, considering you might have Bremstrahlung x-rays from ion/electron beams impinging on not the electrode 22-Apr-20 06:04 PM mm, good point 22-Apr-20 06:06 PM So I went with the route of just scaling up the experiment, due to the very favorable current scaling law of the DPF. Not sure if that was a good choice, because now I'm stuck with some big caps and nowhere to safely operate it, for the moment 22-Apr-20 06:06 PM heh 22-Apr-20 06:06 PM Also rip my cap, one of them swelled 22-Apr-20 06:07 PM i really seriously considered just renting a truck and driving everything out to somewhere unobtrusive in Death Valley 22-Apr-20 06:07 PM oh no 22-Apr-20 06:07 PM i honestly haven't even done any full-charge tests on my caps yet 22-Apr-20 06:08 PM Yeah time for an upgrade, but I've got no money and need to move in like a month 22-Apr-20 06:10 PM part squeamishness, part needing a good excuse to do so.. besides ESI testing, although belljar.net has a whole little doc on exploding wire experiments and I kinda want to try a pulsed hydroforming experiment now 22-Apr-20 06:10 PM from http://www.belljar.net/Exploding_Wires.pdf 22-Apr-20 06:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screen_Shot_2020-04-22_at_6.10.29_PM-68CBA.png 22-Apr-20 06:10 PM i know @Applied_Ion casts shade on can crushers, but any experiment that results in a neat widget afterwards is a win in my mind 22-Apr-20 06:12 PM My caps were from a can crusher lol 22-Apr-20 06:12 PM hehe 22-Apr-20 06:12 PM Clearly used and abused 22-Apr-20 06:55 PM Hey, hydroforming via explosive wires is a legit use lol, no issue with that. Exploding wire systems is a whole field itself, some pretty cool stuff in it from hydrodynamics study to manufacturing to opening switches 22-Apr-20 06:55 PM @qualia technically "can crushers" are one implementation of an interesting form of pulsed electromagnetic crimping and thin metal forming lol, but no one tries actual practical applications other than just crushing cans. I'll give it a pass if you do some pulsed magnetic forming with it though! 22-Apr-20 07:01 PM Wouldn't it work for sort of electromagnetic explosion welding? 22-Apr-20 07:03 PM I don't think the forces are high enough for explosive welding (I could be wrong, don't know specifically). Mainly crimping and forming. Explosive welding is just another level of insane lol 22-Apr-20 07:03 PM You could possibly do very thin sheet, I don't know the forces needed to weld something via physical impact though 24-Apr-20 10:32 PM http://www.additivecomposite.com/shop 3D printable boron carbide neutron shielding 24-Apr-20 10:32 PM only $945 a .. spool? bag? [unspecified quantity] 24-Apr-20 10:52 PM Ah! It's the rubynozzle guy! 24-Apr-20 10:52 PM As the nozzle was created for printing that filament while not contaminating the print with brass or stainless particles. 25-Apr-20 12:17 AM oh neat 25-Apr-20 01:07 AM Apparently the brass contaminants ware activated by neutrons in his experiments and that contaminated his results. 25-Apr-20 04:46 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-0035A.png 25-Apr-20 06:09 PM that is just painful 25-Apr-20 07:01 PM I have some dented G-M tubes that still work. 25-Apr-20 07:01 PM Typically the extruder has a hobbed bolt that digs into the filament to drive it into the extruder. 25-Apr-20 07:01 PM That seems like a major source of metal contamination. 26-Apr-20 10:13 AM Zinc from brass tends to migrate and ruin things. The old timers used to tell me that was the ruin of many experiments early on. 26-Apr-20 11:51 PM hmm...i wonder if a badly chosen inductor is the source of my HV supply woes on these geiger counter boards i am throwing together 29-Apr-20 02:46 AM https://www.nrc.gov/docs/ML1008/ML100840118.pdf 29-Apr-20 03:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-96619.png 29-Apr-20 03:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/tenor-FCD5C.png 29-Apr-20 11:08 AM can't wait to see them do one of these for all the bizarre thorium negative-ion products showing up 29-Apr-20 11:11 AM oh god I'm not sure I actually want to know their real activity 29-Apr-20 11:15 AM also linked from that report https://www.nrc.gov/docs/ML0731/ML073120009.pdf exquisitely thorough report on Radium Timepiece Dose Modeling :D 29-Apr-20 07:13 PM The FDA has "The Broughton File" of all the compiled things I have sent them, for their copious free time, when they're bored. It contains both radiological and laser devices/products. 30-Apr-20 06:05 AM Is it just me, or is it difficult to get pricing for parts from Mirion / Canberra? 30-Apr-20 06:05 AM They want to know end user information, state and country, and fill out a multi page profile with business references. 30-Apr-20 06:05 AM https://tenor.com/Hxfz.gif 30-Apr-20 06:10 AM well 30-Apr-20 06:10 AM afaik they're treating all their products as dual use 30-Apr-20 06:10 AM I had to copy my ID for ortec to send me a manual for a mca 30-Apr-20 10:46 AM ^ 30-Apr-20 10:51 AM Part of that seems to be corporate credit, and I’m happy to pay in advance. 30-Apr-20 10:51 AM I’m hoping to cut through the red tape. Is LND this problematic, too? 30-Apr-20 10:51 AM Just put in an online quote request for an LND 7317. Let’s see what happens.... 30-Apr-20 10:51 AM Then again, NYC wanted to regulate them, so I guess these Geiger tubes must be dangerous.... 30-Apr-20 10:59 AM NYC wanted to regulate them? 30-Apr-20 11:00 AM In 2008. City Council proposal that all Geiger counters had to be registered with NYPD. 30-Apr-20 11:00 AM wth 30-Apr-20 11:00 AM Oh right 30-Apr-20 11:00 AM huh 30-Apr-20 11:00 AM Fear of people misreading them and creating mass panic. 30-Apr-20 11:00 AM Like the Texas glassware law but even sillier 30-Apr-20 11:00 AM do I dare ask 30-Apr-20 11:00 AM heh 30-Apr-20 11:01 AM Texas glassware law? 30-Apr-20 11:01 AM My friend bought a Soxhlet extractor because he didn’t know what it was, but it was banned in Texas. 30-Apr-20 11:01 AM oh wow 30-Apr-20 11:02 AM The laws been changed recently I think 30-Apr-20 11:02 AM because drugs? 30-Apr-20 11:02 AM Just a permit requirement because meth fears 30-Apr-20 11:02 AM texas won't let you buy, like, what.. erlenmeyer flasks? 30-Apr-20 11:02 AM it started at some totally benign piece of glassware and got more exotic from there 30-Apr-20 11:02 AM is meth that much of a problem or is texas the problem? 30-Apr-20 11:02 AM Actually, yes, Erlenmeyer flasks were named explicitly on the Texas list. 30-Apr-20 11:02 AM yes 30-Apr-20 11:03 AM Although NY’s fear of Geiger counters causing a panic may not be unfounded. Look what happened with that bucket of uranium ore in the Grand Canyon. 30-Apr-20 11:04 AM are you allowed to blow your own glassware? 30-Apr-20 11:04 AM or is that like 3d printing a gun 30-Apr-20 11:04 AM this country's drug addiction problems are deathly serious (as someone who (used to, anyways) steps over used discarded needles daily in sf) but also our entire drug war sitch is a horrifying front for massive institutionalized racism at scale 30-Apr-20 11:06 AM My real concern with Canberra has nothing to do with any of this, and is that they may just be jerks about not wanting to do low volume business with individuals who want to repair their own gear they buy on eBay. I brought up NY as sarcasm. 30-Apr-20 11:06 AM that seems like pretty standard behavior i think 30-Apr-20 11:06 AM I saw someone freak out a few weaks ago over a higher count rate point in their driveway 30-Apr-20 11:06 AM weird but kinda makes the fear of radiation argument make more sense 30-Apr-20 11:07 AM i had a very funny freakout when i first discovered that air filters collect radon daughters.. thankfully i managed to restrain myself before flipping out on twitter or something 30-Apr-20 11:07 AM it was in the middle of the CA wildfires and there was just news about a nuclear facility in socal catching fire 30-Apr-20 11:07 AM >.> 30-Apr-20 11:08 AM Yeah, our proper air monitors alpha subtract for that reason. 30-Apr-20 11:08 AM It was weird seeing 670cpm in a single spot on an otherwise fairly cold driveway though 30-Apr-20 11:08 AM @idmb probable cause would probably get you if you're caught skulking around with exotic homemade glassware 30-Apr-20 11:08 AM if they wanna find a way to throw the book at you they will 30-Apr-20 11:09 AM Neighbor’s pet had a radiopharmaceutical and did its business? 30-Apr-20 11:09 AM Maybe? 30-Apr-20 11:09 AM Ought to see if the spot is still there 30-Apr-20 11:10 AM I heard someone got stopped in the tunnel to NYC because of a pet that was radioactive due to nuclear medicine. 30-Apr-20 11:10 AM Texas law: https://www.dps.texas.gov/RSD/Precursor/Laws/index.htm 30-Apr-20 11:12 AM Oh wow 30-Apr-20 11:13 AM I think @funranium would be in trouble in Texas. Doesn’t BBotE production require a filtering flask and Büchner funnel? 30-Apr-20 11:13 AM My home setup would be wholly illegal in texas 30-Apr-20 11:14 AM ostensibly he runs it as a business and has good reason for owning it all 30-Apr-20 11:16 AM The permits weren't too hard to get if I remember correctly 30-Apr-20 11:18 AM Wow. Submit a web form to LND. 8 minutes later: 30-Apr-20 11:18 AM Hello Ryan, The unit price for the LND 7317 is $ 110.00 each, we can ship in about 15 days. UPS ground shipping is $ 15.00. LND will accept payment with Visa, Mastercard or American Express. Please let me know if you need any further information. 30-Apr-20 11:18 AM Oh damn, nice 30-Apr-20 11:18 AM sweet 30-Apr-20 11:18 AM Someone’s got good customer service and wants my money. 30-Apr-20 11:18 AM also less expensive than expected 30-Apr-20 11:21 AM I’m also trying to see if I can find the weird low range Geiger tube in the ADM-300. It’s got a mica end window, but it’s also got an energy compensation lead sleeve for gamma. My tube is good, but someone I know has one that I am guessing may have a popped window. 30-Apr-20 11:28 AM LND is great for customer service. only complaint i have heard about them, and sorta experienced myself, is the specs of their tubes sometimes change while the number stays the same 30-Apr-20 01:24 PM https://github.com/sandialabs/InterSpec 30-Apr-20 01:24 PM Okay I don't know how is it I've missed this until now, but InterSpec is AMAZING! 30-Apr-20 01:24 PM It puts any gamma spectrum analysis software to shame! Super intuitive to use, and does almost anything you want. I love the built in photopeak library that would automatically match your peaks and plot them on the same graph with relative intensities 30-Apr-20 01:24 PM It includes info on the decay as well 30-Apr-20 01:26 PM does it speak with the mca or do you just feed it a spectrum file? 30-Apr-20 01:27 PM You feed it any spectrum file, doesn't capture data, but it can read anything you throw at it and convert between different formats 30-Apr-20 01:27 PM In that sense it's a complete replacement of Cambio, also by Sandia 30-Apr-20 01:27 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-34C8C.png 30-Apr-20 01:27 PM It’d be nice for it to have the ability to calculate activity 30-Apr-20 01:28 PM You can do quadratic energy calibration across multiple files with unlimited number of points 30-Apr-20 01:28 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5F3DB.png 30-Apr-20 01:28 PM It can calculate activity! 30-Apr-20 01:28 PM There's an entire activity/shielding calculator built-in 30-Apr-20 01:28 PM It can? I might just have never worked out how then 30-Apr-20 01:29 PM Just gotta identify all your peaks and it will fit it for you 30-Apr-20 01:29 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-67E69.png 30-Apr-20 01:29 PM Of course accurate detector efficiency calibration is necessary, which I haven't done 30-Apr-20 01:29 PM A short intro presentation: https://www.osti.gov/servlets/purl/1597194 30-Apr-20 01:29 PM Gotta love peak-fitting with just a double click, and how it fits the continuum automatically when you do it 30-Apr-20 01:33 PM Even with a detector efficiency calibration, it always sort of feels clunky compared to what I'm used to 30-Apr-20 01:33 PM What are you used to? 30-Apr-20 01:33 PM Everything else is really nice about it though 30-Apr-20 01:33 PM Ortec Gammavision, so I mean free versus a few thousand dollars 30-Apr-20 01:33 PM Cant really complain 30-Apr-20 01:33 PM Because worst case scenario I just do activity calculations in an excel spreadsheet. 30-Apr-20 01:35 PM Ah... Yeah well I was used to Cambio and other free stuff... It's also open source, so it should be possible to implement a sound card MCA into this as well 30-Apr-20 01:35 PM Seems like detector calibration was a bit off, and you can see that so obviously with these photopeaks 30-Apr-20 01:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D062C.png 30-Apr-20 01:39 PM That would be darn interesting to see. Interspec has been my go to for when I'm away from work computers for a while 30-Apr-20 01:40 PM Oh you can get it on your phone as well! Imagine the world's first free mobile sound card MCA! 30-Apr-20 01:40 PM And you can do all your analysis right there on your phone or tablet. It's fully featured on mobile 30-Apr-20 01:45 PM hmm.. time for a usb-c photomultiplier base.. 30-Apr-20 02:07 PM Found a bug, you can't select no background when you have background subtraction enabled, will crash it immediately 30-Apr-20 02:07 PM The only thing I don't like is that you can only plot 3 spectra at once, although you can import as many as you like 30-Apr-20 02:44 PM I’ve been looking for good free analysis software. 30-Apr-20 02:44 PM This looks really cool. 30-Apr-20 02:54 PM is there a good open/standardized format for spectrum data i should focus on massaging my Series 35+ output into? 30-Apr-20 03:06 PM besides 'csv' i guess 30-Apr-20 03:07 PM I've been using .spe or .spc 30-Apr-20 03:07 PM All are just ASCII spectrum file formats I think 30-Apr-20 03:07 PM You can use InterSpec to convert between any of them. Including csv 30-Apr-20 03:31 PM oh, TIL .spe is very close to what my MCA outputs already 30-Apr-20 03:31 PM courtesy of https://inis.iaea.org/collection/NCLCollectionStore/_Public/24/030/24030393.pdf 30-Apr-20 03:32 PM It used to be that there are so many formats that Sandia had to put out a software just to convert between different file formats 30-Apr-20 03:32 PM This is literally all it did 30-Apr-20 03:32 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A534B.png 30-Apr-20 03:32 PM It displays the spectrum, gives you a few details, and the only thing you can do is save it to a different file format 30-Apr-20 03:32 PM This capability is of course retained in InterSpec, so no reason to use Cambio now 30-Apr-20 06:17 PM Was going through some stuff up at my grandpa's house today (he passed around Easter) and found a Nuclear Bomb Effects Computer paper dial reference... 30-Apr-20 06:17 PM Knew he worked on that sort of stuff for a short time in his career but did not expect to find any neat stuff like this 30-Apr-20 06:17 PM Will try to scan it a bit later 30-Apr-20 09:58 PM TX controls a great deal of scientific glassware and equipment on the grounds of "meth production precursors". Expect a nice visit from the TX Rangers if you order interesting things from VWR. They can, and will, tear your home apart for cause as you hadn't registered with them. They will then be back every year to make sure you still have everything and haven't passed it off to drug traffickers without telling them. 01-May-20 07:14 AM Just try driving a panel van across Texas and you will figure that out! It wound up just being easier to strip out the walls, carpet, and access panels before the trip so they would not do it on the road side anyways. It’s really the worst part about going there. If you have out of state plates they done like it. Especially California or Nevada plates! 01-May-20 09:37 AM Set the "Nuclear Bomb Effects Computer" for 100KT at 1mi. Neat little thing! 01-May-20 09:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200430_182942838c-4BCBB.jpg 01-May-20 10:07 AM sweet! 01-May-20 10:15 AM i wonder what sort of copyright baggage exists on that design/info... 01-May-20 10:15 AM would be neat to make some reproductions of it to hand out 01-May-20 10:16 AM There’s a version online to be cut out 01-May-20 10:16 AM oh nice, someone already did it then 01-May-20 10:17 AM https://www.fourmilab.ch/bombcalc/brico.html 01-May-20 12:03 PM Well Mirion / Canberra got back to me. It looks like it was just an export control formality, and they accepted my info as an individual. 01-May-20 12:03 PM That said, $238 for what looks like the same pancake that LND is selling for $110. 01-May-20 03:08 PM @funranium Heh, VWR is like that. 01-May-20 03:08 PM I used to know a guy who got a police visit because he dared to order a catalog from VWR as a civilian. 01-May-20 03:13 PM good to know >_> 01-May-20 03:13 PM @rfs was he in Texas? 01-May-20 03:13 PM i love ordering free dead-tree catalogs from big manufacturers, they make good bathroom reading 01-May-20 03:14 PM @rdpierce Nope, Finland. 01-May-20 03:14 PM And I heard this after ordering my catalog, but did not get vanned. 01-May-20 03:14 PM This was +10years ago 01-May-20 03:14 PM @qualia And I agree. 01-May-20 03:14 PM Also good for propping stuff up 01-May-20 03:14 PM Fischer's old literature portal also did product samples, so I got some biology stuff as samples with the catalog :D 01-May-20 03:15 PM who needs lab jacks when you've got MDC, ISI, and far too many old Sweetwater catalogs kicking around 01-May-20 03:16 PM Edmund optics still sends me catalogs 01-May-20 03:16 PM The Sigma-Aldrich catalog used to be hardbound and larger than a CRC. 01-May-20 03:16 PM takes wistful stroll down memory lane 01-May-20 03:16 PM My 2008 Sigma-Aldrich catalog is a hard cover and very thick 01-May-20 03:16 PM got it as a poor-boy reference book. 01-May-20 03:17 PM It got used for that a lot during O-Chem labs by everyone 01-May-20 03:17 PM For that exact reason 01-May-20 03:21 PM my father always kept the bathroom stocked with Edmund Scientific catalogs and I never realized that they and Edmund Optics were the same folks until now 01-May-20 06:12 PM I wish fisher still had a complete catalog. I love looking at ones from decades past online 01-May-20 11:15 PM solved my power supply issues for my mini geiger boards... and it works! 01-May-20 11:15 PM need to get the display code written and decide how exactly i want to display stuff but i think i might be able to squeeze the LND714 tube, boards, display, and battery into around 2.5" x 1.5" x 0.375" 02-May-20 05:53 AM https://www.youtube.com/watch?v=h0dF2FUo5WU 02-May-20 12:23 PM I used to have a mr wizard book of experiments when I was a kid 07-May-20 05:45 AM It looms like the professionals have discovered what we’ve known for some time: 07-May-20 05:45 AM Vintage electronics can detect radiation. 07-May-20 05:45 AM https://twitter.com/casillic/status/1258302161697587201?s=21 07-May-20 05:48 AM there's been a bigtalk about that at some ccc event iirc 07-May-20 05:48 AM (also why is there cobalt 60 in the warhead) 07-May-20 05:48 AM https://media.ccc.de/v/34c3-8994-vintage_computing_for_trusted_radiation_measurements_and_a_world_free_of_nuclear_weapons Found it! 07-May-20 06:30 AM I think this is the same group. 07-May-20 06:30 AM The paper mentions presenting at CCC. 07-May-20 06:30 AM Also this open source system looks interesting: 07-May-20 06:30 AM https://ukni.info/project/information-barrier/ 07-May-20 06:45 AM Ok, is this a typo: 07-May-20 06:45 AM https://ukni.info/mdocs-posts/ibtoplevelalgorithmv1-2/?mdocs-file=453&mdocs-url=false 07-May-20 06:45 AM The algorithm mentions an Am-241 peak at 662 keV. That’s Cs-137. 07-May-20 06:45 AM Is that a typo, or does Am-241 also have a peak there? 07-May-20 06:54 AM Yeah, Am-241 to Np-237 via alpha decay, 662.4 keV 07-May-20 06:54 AM But compared to the 59.5 keV peak, it's about 6 orders of magnitude less significant 07-May-20 07:06 AM Due to its half-life, it's almost certainly not as significant as Cs-137 for most common samples 07-May-20 07:13 AM https://en.wikipedia.org/wiki/Plutonium-241 07-May-20 07:15 AM Yeah, Am-241 to Np-237 via alpha decay, 662.4 keV @Mason_Yu ...oh! I must have missed that peak completley and thought my smoke detectors had Cs in them 07-May-20 07:15 AM By comparing the area under the three peaks, you should be able to get some idea of what the age of the plutonium is 07-May-20 07:15 AM You'll certainly see it with an HPGe! Not visible for plebs like me though 07-May-20 07:19 AM depends on the activity ^^ 07-May-20 07:24 AM Well for a puny 1.5" NaI scintillator to see it, it will have to be a truly terrifying drop and run source 07-May-20 07:24 AM Or wait till eternity 07-May-20 09:09 AM This is making my skin crawl!!! 07-May-20 11:14 AM The application for this is using HPGe to detect isotopic ratio of Pu in nuclear weapons being destroyed. 08-May-20 05:57 AM Amusing-- reminds me of an improvised design using a large green LED as a rudimentary diode based detector 11-May-20 06:15 AM https://www.youtube.com/watch?v=WiBKSVZH5GQ 11-May-20 08:14 AM I did something like that a few years ago, had to use a pretty big correction factor to account for cesium being fairly volatile. 14-May-20 03:10 AM found a new (old) 'fissile' symbol, courtesy of hanford: https://twitter.com/profanegeometry/status/1260874738089357312 14-May-20 03:10 AM very important 3 am research 14-May-20 03:10 AM ohh, cool 14-May-20 07:54 AM https://twitter.com/cern/status/1260600298206302210?s=21 14-May-20 09:59 AM https://www.orau.org/ptp/Library/cdv/Ten%20for%20Survival.pdf 14-May-20 09:59 AM found a copy of that and another civil defense guide when cleaning at my grandparent's yesterday 14-May-20 09:59 AM really neat window into the mindset of the 1960s 14-May-20 09:59 AM this was the other one: https://www.orau.org/ptp/Library/cdv/In%20Time%20of%20Emergency.pdf 14-May-20 12:13 PM That’s one for the collection. 14-May-20 08:32 PM So does anyone here have a working dental x-ray imager? 14-May-20 08:32 PM https://www.ebay.com/itm/Gendex-GXS-700-Digital-Radiography-X-ray-Dentist-Dental-USB-Sensor-SIZE-1-One/333466331251 14-May-20 08:32 PM This seems too cheap/good to be true... 14-May-20 08:36 PM likely failed sensor 14-May-20 10:50 PM At that price it might be worth the risk 14-May-20 10:50 PM Just buy a few of them and take a gamble... Even if only one of them works it would be well worth it. John McMaster has done some impressive work on it: https://github.com/NucWiki/gxs700 14-May-20 11:10 PM Given what john mcmaster has said over time, I'm lead to believe the bond wires on the sensors fail on a regular basis, there's no pratical fix for it 14-May-20 11:12 PM Hmm, hence why it's a gamble 14-May-20 11:50 PM Interesting. What would cause such a failure over time? 14-May-20 11:56 PM I believe it's just from rough handling and mechanical shock. It doesn't look like a super expensive thing, so people don't often exercise enough care. There are apparently exposed bond wires between the CCD and the PCB, those would be the first to fail I think 15-May-20 12:01 AM Hmm n.b. this is the small size, not the primary device developed for. https://siliconpr0n.org/media/mtvre/2018-01-11_john_m_gxs-700_x-ray_sensor_part2.pdf 15-May-20 12:01 AM The interface is totally different, though after a large update support was added on request from a paying customer 15-May-20 12:01 AM For sufficiently recent Linux kernels and only on the metal, no VMs 15-May-20 12:01 AM Main implication is only quite small objects can be imaged though 15-May-20 12:04 AM Yeah film is pretty much the only affordable option for bigger stuff 15-May-20 12:04 AM https://www.ebay.com/itm/401932558716 15-May-20 12:05 AM Needs a driver too 15-May-20 12:06 AM Yeah it needs a separate box, probably needs quite a lot of reverse engineering 15-May-20 12:06 AM Unless that box shows up on eBay again 15-May-20 12:06 AM You can also just point a digital camera of some kind at the screen directly fwiw, but you would want a long enough exposure time and alignment would be annoying. 15-May-20 12:06 AM Both spatially and temporally 15-May-20 12:08 AM I know, but image quality is on a completely different level with flat panel detectors. You have noise from x-ray exposure on your camera, ambient light, probably need a lot of post processing. Long exposure time also means higher dose 15-May-20 12:09 AM The intent is to trigger remotely or on a matched time delay, but yes the rest is true 15-May-20 12:09 AM X-ray films are super cheap ($40 for a pack of 100 25cm*30cm), and once the developing and fixing process is dialed down it's not that big of a problem 15-May-20 12:09 AM In terms of contrast and resolution, for larger things it's not as important. 15-May-20 12:09 AM It's always possible to stich images together from a smaller dental detector too. That's a sacrifice I'm willing to make to not pay the thousands of dollars for a flat panel detector 15-May-20 12:09 AM http://physicsopenlab.org/2018/02/28/digital-radiography-diy/ 15-May-20 12:09 AM I'm also quite impressed by this. No scintillators whatsoever! 15-May-20 12:09 AM And I wonder how far this can be pushed with a better (yet still sacrificial) CMOS detector 15-May-20 12:35 PM I still think directly pointing a camera in a tripod on top of the tubehead at the phosphor panel from a cassette placed some distance behind the target object may be adequate for objects up to about 10cm x 10cm or so. For views through larger equipment, though, film is probably best I agree. 15-May-20 01:28 PM I'd use a mirror and place the camera well out of the way. Backscattered x-ray represent a pretty significant dose. Doesn't take a lot to ruin a good camera with a few dead pixels 15-May-20 02:31 PM Didn't say a good camera, and you're the one who just suggested direct beam impingement on a CCD 15-May-20 02:31 PM Still, I agree the suggested alternatives are also valid for some use cases 15-May-20 02:31 PM Just want to take a moment of regulatory warning for this. Keep this at the hobbyist level and mind the other side of the wall where you're working. Do not take on imaging work for others, do not advertise services, and hooboy do not charge money. You run the risk of accidentally becoming a radiographer subject to some rather stiff licensing requirements. 15-May-20 02:31 PM Carry on. 15-May-20 02:32 PM Oh of course. 15-May-20 02:32 PM Actually part of the benefit of using time delays or remote triggers is the ability to vacate the area when the tube is energized. 15-May-20 02:32 PM Backscatter can be substantial and it's best to be somewhere with minimal exposure. 15-May-20 02:34 PM No one is going to be in the same room when the tube is energized. And I need a lot of lead, sheets and bricks 15-May-20 02:34 PM I did not think the direct CCD imaging is a practical approach 15-May-20 02:35 PM Yes eBay is a good source for lead sheets 15-May-20 02:36 PM I really didn't expect you could get an image really, because you are just looking at the noise from the x-ray effectively. Also, CCD and CMOS would work very differently with direct exposure 15-May-20 02:36 PM I don't think direct conversion with a CCD is possible actually 15-May-20 02:36 PM But it would be really interesting if it is possible! 15-May-20 02:36 PM Would replace (at a hobbyist level) expensive and bulky intensifier tubes 15-May-20 02:36 PM And think of the speed! 15-May-20 02:36 PM Imagine a high speed x-ray movie... How I wish my Hadland Imacon had a CsI phosphor screen 15-May-20 02:36 PM Actually that wouldn't work, I'd just get a blur from frame-to-frame 15-May-20 02:49 PM Pulsed X-ray tube? 15-May-20 02:49 PM Flash radiography is one application I'm really interested in for the plasma focus project 15-May-20 02:49 PM It would provide x-ray with effective kVp at around ~100 keV (adjustable via fill gas and target material). And neutrons would be an option as well 15-May-20 02:49 PM It can be considered "microfocus" because emission spot of the neutrons and x-rays are on the order of 50 to 100 microns 15-May-20 02:49 PM But to expose in one shot means you need a big machine, probably way too big for a hobbyist at home 15-May-20 03:02 PM Yeah, I’d imagine it’d have to be very large 15-May-20 03:05 PM Well the physical size of the vacuum chamber and electrodes would be fairly compact. Even including the capacitors and power supply, it would be around the same size and weight as a typical SEM. Most of the energy emitted would be in the soft x-ray range around 30 keV. Depending on the fill gas, the ionization k-line would likely dominate 15-May-20 03:05 PM That component is easy to shield, but not the high energy bremsstrahlung from the ions and electrons 15-May-20 03:07 PM the emission spot might be that small but iirc the radiation pattern emitted is conical 15-May-20 03:07 PM Which is an advantage! 15-May-20 03:07 PM The main issue is just the inconsistency from shot to shot 15-May-20 03:07 PM If some form of collimator is added, then the intensity would not be enough 15-May-20 03:07 PM And yeah this is well into the realm of industrial radiography, definitely need more than a tiny lead castle to do this safely. I'd imagine regulatory constraints will limit the size of any flash radiography machines 15-May-20 03:07 PM There's really nothing it would be particularly useful for neither (on a hobbyist level) 15-May-20 03:07 PM They use it to look at ballistics, armor, explosion, hypersonic stuff...etc. It would be nice to look inside a working engine, that's the only application I'm personally interested in 15-May-20 03:25 PM i wonder if the wonky spread of plasma focus line radiation is at all suitable for grazing incidence focusing 15-May-20 03:25 PM also i can't imagine there's any size of flash radiography machine that isn't subject to regulatory constraint >.> 15-May-20 03:25 PM though, idk, lots of locales/agreement states out there 15-May-20 03:34 PM Well if x-ray optics work with the plasma focus, then it could greatly improve its viability for radiography applications. I don't think you necessarily need a monochromatic source to make use of grazing incidence reflection for x-rays, and polycapillary optics can focus a range of x-ray energies 15-May-20 03:34 PM Of course any spectral information would be lost in the optics, but that shouldn't be a big concern for radiography applications 15-May-20 03:34 PM I don't think they make these things large enough to image anything useful though 15-May-20 03:34 PM https://directconversion.com/technology/ 15-May-20 03:34 PM That's very impressive! I wonder how much one of their direct conversion imaging panels cost 15-May-20 03:34 PM My guess is >$1 mil 16-May-20 07:35 AM High speed x-ray photography: that’s a good application for a synchrotron light source. 16-May-20 07:35 AM How did they do it in the good old days? Wasn’t there high speed x-ray photography used to test the implosion mechanisms for the Manhattan Project? 16-May-20 07:47 AM just big pulsed accelerators afaik 16-May-20 09:05 AM Marx generators work nicely from my reading 16-May-20 11:16 AM I wonder how many people on the Manhattan project were the 16-May-20 11:16 AM “Don’t bother testing it, the calculations are right, it will work” type 16-May-20 11:42 AM I mean it was correct for the gun type 16-May-20 08:28 PM Yeah. I don’t believe there were any tests on the gun type, apart from the deflagration tests on the cordite. 16-May-20 08:28 PM Feynman mentions how hap hazard it was at oak ridge in his book. 19-May-20 05:27 AM finally on my way to customs to pick up my neutron detectors <3 19-May-20 06:48 AM aaaaa 19-May-20 06:48 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200519_154541-DB45C.jpg 19-May-20 01:34 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200519_223025-E3265.jpg 19-May-20 01:34 PM they all go into corona discharge with not too big of a variance for current 19-May-20 01:34 PM I'll call that a success 19-May-20 02:04 PM Nice.... 19-May-20 02:04 PM Helping an acquaintance out. Have any of you ever heard of a small Russian pocket Geiger counter that is labeled Pioneer with an STS-5 tube and a 1958 date? 19-May-20 02:04 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-91A47.jpg 19-May-20 02:04 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image1-077B4.jpg 19-May-20 02:04 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image2-92F04.jpg 19-May-20 02:06 PM never heard of it, no 19-May-20 02:06 PM but the sts5 is basically just an sbm20 19-May-20 02:06 PM woot that cap on the right 19-May-20 02:06 PM that's a precision capacitor 19-May-20 02:08 PM How can you tell? 19-May-20 02:08 PM The one labeled 0.05 uF? 19-May-20 02:10 PM yeah that's the one 19-May-20 02:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200519_230958-3AC3A.jpg 19-May-20 02:10 PM because I have this cap from eastern germany labeled precision capacitor 19-May-20 02:10 PM the rest is an assumption 19-May-20 02:11 PM Is the STS-5 a military tube? 19-May-20 02:11 PM not sure if they had a differentiation between military and civilian 19-May-20 02:11 PM There’s virtually nothing in the box. All it can do is flash a light or maybe there’s a clicker. 19-May-20 02:11 PM but the sts5 / sbm20 is what was in pretty much every single counter from them 19-May-20 02:12 PM Soviet military electronic components generally have diamond inspection stamps. 19-May-20 02:13 PM hmm 19-May-20 02:13 PM no idea about that 19-May-20 02:13 PM from what I gathered the sts5 is just older 19-May-20 02:19 PM The two caps on the left have the diamond mark. Those are military. 19-May-20 02:19 PM From what I heard, the Russian military got the best, most reliable electronics components. Civilians got what was left over. 19-May-20 03:26 PM speaking of russians 19-May-20 03:26 PM https://twitter.com/GigaBecquerel/status/1262868083502387201 20-May-20 07:15 AM Well that thing is the transistor that drives the transformer. The long sticks next to the counter tube look like bad copies of Victoreen precision multi megohm resistors. 20-May-20 07:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-1A976.jpg 20-May-20 07:15 AM This is what passed for a miniature Transistor in the Soviet Union in the 50’s 20-May-20 07:15 AM The cap to the far right is a high voltage cap. Probably the collector cap for the high voltage. There appears to be a molded rectifier or another high voltage cap buried down below. The little brown box. 20-May-20 07:15 AM Actually after further consideration the big silver transistor if probably the detector switch. The little cap is probably the coupling cap to the transistors base. 20-May-20 07:15 AM I would guess the device next to the lamp and transformer with the black plastic on top is what drives the booster transformer. 20-May-20 07:15 AM Anyways without being able to examine it in person that’s my two cents. 20-May-20 07:15 AM Looks pretty basic. Nothing in there apart from the counter tube has a real life span so it would clean up and work. No telling how much exposure it’s gonna take to make it work though. Probably not the most sensitive. Probably more like a doomsday grade device. 20-May-20 09:26 AM Think the STS5 tube is more sensitive than the "doomsday" sort of counters... https://www.pocketmagic.net/tube-sts-5-%D1%81tc-5-geiger-tube/ 20-May-20 10:55 AM I see no calibration means anywhere on the unit. Direct example of the soviet method. Good enough but not a single bit better as that would be a waste of state resources! 20-May-20 11:16 AM @rdpierce I do not speak or read Russian beyond where google translate gets me but there seems to be a lot of discussion of them here: http://forum.rhbz.org/topic.php?forum=2&topic=44 20-May-20 11:16 AM some neat photos of the 1959 model in that thread 20-May-20 11:45 AM T!ANKS @LRM !!!! 20-May-20 11:45 AM I see mention of a gas voltage regulator. Is that like the "corotron" in some of the CDV-700 Geiger counters, which functions similar to a Zener? 20-May-20 03:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200520_141543-993CF.jpg 20-May-20 03:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200520_141615-2265C.jpg 20-May-20 03:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200520_163344-1B666.jpg 20-May-20 03:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200520_222308-D82DD.jpg 20-May-20 03:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200520_230418-6B058.jpg 20-May-20 03:10 PM the detector is taking shape 20-May-20 03:10 PM the holders for the tubes are currently printing, and I need to buy some Al flat stock as holder for the preamps 20-May-20 03:38 PM looks like fun, wish i could justify buying a couple more of those tubes but i do not even really need the single one i have 20-May-20 03:41 PM well 20-May-20 03:41 PM need 20-May-20 03:41 PM 'tho if you want one, they won't get much cheaper than now 20-May-20 03:41 PM market is basically saturated, they're even selling packs of 100s 20-May-20 08:00 PM Nice quick machining-- looks like it will be very mechanically robust 21-May-20 05:23 AM https://www.frm2.tum.de/fileadmin/w00bnv/www/_migrated_content_uploads/TUM-Industrietag_Schillinger.pdf Some very nice info on neutron radiography 21-May-20 07:49 AM I saw that dynamic neutron radiograph "movie" of a running engine, and got very disheartened because the flux required to do that is just too high 21-May-20 07:49 AM It was interesting to see different approaches of making neutron imagers though, and as large CCD costs come down gradually and units become more commercialized, most implementations won't be restricted by the detector pixel size, but by the statistics due to a low neutron flux/relatively low detector efficiency 21-May-20 07:57 AM yep 21-May-20 07:57 AM I was thinking about bilding sth myself, maybe a big x-ray pixel detector covered in Gd foil or similar# 21-May-20 07:57 AM but I'll never get those fluxes needed for any useful applications 21-May-20 07:58 AM The tricky part is the image "collimator", think of it as a MCP, but for x-rays or scintillation light 21-May-20 07:58 AM You can use some telecentric optics to help if it is a scintillating screen 21-May-20 07:58 AM Probably the only feasible way to do it at home 21-May-20 08:04 AM I can get my hands on some ready made medical x-ray detectors, that already do all the collimating 21-May-20 08:04 AM CsI on CCD iirc 21-May-20 08:04 AM and if the neutron sensitive layer is thin enough & directly on the scintillator that should not be an issue 21-May-20 08:05 AM But the gamma goes in all directions, so your spatial resolution won't be very good. To start with, perhaps try putting your foil on top of a film and see the effect 21-May-20 08:05 AM sure, some resolution will be lost, but eh 21-May-20 08:06 AM Apparently there are also specially formulated phosphor that can luminesce when scanned with a laser after they are activated with neutrons 21-May-20 08:06 AM That's how Fujifilm makes their neutron imaging plates 21-May-20 08:07 AM with Gd you'll mainly get reactions from Betas, the high energy gammas will go straight through the scintillator iirc 21-May-20 08:07 AM but that's all just a dream so far, no sense in building a detector I can't test 21-May-20 08:07 AM Apparently there are also specially formulated phosphor that can luminesce when scanned with a laser after they are activated with neutrons That sounds a lot like OSL dosimetry as well 21-May-20 08:08 AM Fujifilm imaging plates 21-May-20 08:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Imaging-143D1.pdf 21-May-20 08:08 AM The more things added to an imaging system and the less compact your detector is, you inherently loose out detection efficiency. And at some point, what is gained on the increased spatial resolution may not be worth it because again, statistical noise would be dominant 21-May-20 08:08 AM And for most radiographic systems, the contrast and resolution of the final image isn't limited by the detector anyway! True for x-rays, even more so for neutrons 21-May-20 08:08 AM To exploit techniques such as phase contrast imaging described in the paper, you need high spatial coherence, which means good collimation, which means a bigger source... 21-May-20 08:08 AM So yeah, the main point is the limiting factor is really the source, not the neutron imaging system 21-May-20 08:08 AM @GigaSquirrel I also believe indium, gadolinium or dysprosium would perform better than gold as a neutron conversion foil 21-May-20 08:08 AM Indium foil is particularly the most affordable option, unless you can get you hands on some gadox screen 21-May-20 08:27 AM I never mentioned gold, just Gd ^^ 21-May-20 08:28 AM Ah, I've never been very good at chemistry lol 21-May-20 08:29 AM foil would be hard to get thin enough to get low enough self absorption of the resulting betas, I'd rather evap some high cross section stuff onto "neutron transparent" foil 21-May-20 08:29 AM Gd is pretty cheap on ebay so my first try would be Gd on Household Al foil 21-May-20 08:29 AM Here is the quantitative relationship to calculate image sharpess 21-May-20 08:29 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5E7CF.png 21-May-20 08:29 AM Ignoring self-shielding, so the optimal thickness depends on the beta energy from the conversion foil 21-May-20 08:29 AM As a general rule of thumb, converter foil should be less than 0.5 mm thick 21-May-20 08:43 AM I think the best price-to-performance is probably film sandwiched between indium foils (also used for thermal interface applications, so prices are pretty low) 21-May-20 08:43 AM Considering most applications are under low flux 21-May-20 08:43 AM In particular, this tested combination 21-May-20 08:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4AA54.png 21-May-20 08:43 AM 90 micron resolution is like state-of-the-art for digital imagers 21-May-20 08:43 AM Now, the flux required is still pretty high, but it's like within reach at least, much better than what's required for digital sensors lol 21-May-20 08:57 AM 10 cm * 10 cm * 0.5 mm of 99.995% indium foil is like $36 only, that's super cheap 21-May-20 08:57 AM And the half-live of the beta decay of In-116 is only 54 minutes, so the activity does saturate pretty quickly 21-May-20 08:57 AM Man, I should've thought of this sooner lol, wasn't actually expecting the flux number to be this low 21-May-20 08:57 AM Should've proposed an experiment using the LINAC neutron source at my school, the flux would've been enough to do some serious high resolution neutron imaging. Although some work was done in the past, most of it was focused on huge things like solid rocket boosters for the space shuttle, not small things 22-May-20 01:19 AM Hmm yes I was thinking about neutron imaging a while ago and came to similar conclusions. Probably a Marx generator and a flash x-ray tube would be more practical, but of course the absorption coefficients for materials are very different between the two of them etc 22-May-20 01:23 AM Neutron imaging in general is only for pretty specialized applications, detecting sensitive low-Z materials like explosives and fluids while seeing through thick metal at the same time. X-ray radiography remains by far the easier and more universally applicable option, but I now think both can be done at home 22-May-20 01:31 AM Interesting-- watching for further commentary 22-May-20 01:31 AM One thing to note is that the film factor for Eastman AA film is not the lowest one possible (lower the film factor, lower the exposure time required for a given source strength). I think modern alternatives exist that can be 3 to 5 times faster/more sensitive than the AA film. This means a further reduction in flux required. Unfortunately it's still too much for a regular fusor 22-May-20 01:33 AM What would your proposed small scale alternative be? 22-May-20 01:33 AM Even the Eastman KK film from the same era is 3 times more sensitive (in general) than the AA film, details depends on the type of radiation 22-May-20 01:33 AM I think a well optimized plasma focus filled with deuterium with capacitor bank energy ~5 kJ would provide sufficient flux in a few hundred shots 22-May-20 01:33 AM Assuming about 30 cm distance to object, we need about high 10^8 to low 10^9 neutrons per shot accounting for the anisotropy of neutron emission. Funny thing is, fill the same machine with argon or xenon, and you get a very good x-ray radiograph in one shot 22-May-20 01:33 AM The image quality taken with the plasma focus is not bad at all. I'd say something like this could've been mistaken for a radiograph taken with a microfocus tube 22-May-20 01:33 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-40633.png 22-May-20 03:19 AM Impressive 22-May-20 04:17 AM One major advantage is that you can reach beyond 100 kVp with some clever design features on the electrode and high-Z x-ray generating target, while only getting up to 30 kV or so in capacitor voltage 22-May-20 04:17 AM So you can use cheaper and higher power capacitor charging supplies, 1 kW charging power is quite easily within reach for amateurs 22-May-20 09:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200522_173538-2B25F.jpg 22-May-20 09:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200522_174246-B627F.jpg 22-May-20 09:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200522_174302-3845C.jpg 22-May-20 10:25 AM And the seller of those tubes has contacted me if I want to build him a test stand for those tubes 24-May-20 06:22 PM https://www.youtube.com/watch?v=nEracrXk5f8 Finally made a video of a quick test of a little geiger counter board I made, 30x49mm, to go with the little LND714 tubes I picked up. Need to try to find a smaller/thinner piezo speaker that sounds "right" once the STM32 boards arrive to do the counting and run the display. 24-May-20 06:25 PM sweet 25-May-20 02:56 AM cute! 26-May-20 04:17 PM Been going through some more of the photos on the national archives website. Looks like someone forgot to remove the SECRET sticker from this...and an explosive in a photo labeled "neutron generator" (???) is something I would want no part in... https://catalog.archives.gov/id/75454503 26-May-20 04:17 PM Also here is a massive stack of wax blocks https://catalog.archives.gov/id/75454547 26-May-20 05:20 PM yellow tape! 26-May-20 05:20 PM Casillic on twitter did a big thread of yellow tape sightings a while ago, aimed gently in scott carson's direction. it bears some mysterious significance 26-May-20 05:20 PM i'm amazed that bare paraffin blocks were used as often as they were 26-May-20 05:20 PM stuff melts way too easy 26-May-20 05:20 PM ..then again, i guess it's all about to be consumed in nuclear hellfire 26-May-20 05:27 PM i just saw some photos of i think just that pile after the shot, what a mess but things look more thrown around than nuclear hellfire. https://catalog.archives.gov/id/75454901 + https://catalog.archives.gov/id/75454903 26-May-20 05:28 PM It’s not just a puddle 26-May-20 05:28 PM I’m surprised 26-May-20 05:29 PM that is the least aesthetically appealing destruction 26-May-20 05:29 PM 20 kt weapons effect test in a closed underground steel tunnel lined with neutron detectors and calorimeters 26-May-20 05:29 PM Unfortunately, 14 people were injured and 1 killed in a very similar test 26-May-20 05:29 PM Due to the ground caving in after the test 26-May-20 05:29 PM There are some closer pictures of neutron generators initiated by explosives: https://catalog.archives.gov/id/75473445 26-May-20 05:29 PM And ones with a high voltage pulse (with yellow tape): https://catalog.archives.gov/id/75489417 26-May-20 05:37 PM reminds me of that time i found a paper on D-O explosively pumped neutron generation and a twitter mutual was like 'Oh yeah I use that copper hemisphere as a flower pot now' https://twitter.com/A_J_Higgins/status/1092447073880936448 26-May-20 05:55 PM Oh it's like a mini-pure fusion neutron bomb. Unfortunately it does not scale well and the neutron yield is not enough to compete with sealed D-D or D-T tubes. 26-May-20 05:55 PM Good lessons to be learnt from it though, in particular that NE102 plastic scintillator is probably good enough for decent resolution TOF! 26-May-20 05:57 PM I saw someone mention Scott Carson. Is he still on Twitter? 26-May-20 05:57 PM I thought he deleted his account. 26-May-20 05:57 PM Apparently he's got a novel in progress, as well as some memoirs of humorous encounters through the years. I nearly fell over laughing while reading about the drunk shenanigans involving stealing a golf cart to perform a daring heist of cases of beer from the CO's residence on Johnston Atoll, only to find that the CO was actually home but in flagrante delicto, and the golf cart got driven over the edge of the atoll and into the ocean. 26-May-20 09:09 PM oh that's amazing actually 26-May-20 09:09 PM i found out about him because .. with one of his accounts.. he faved one of my posts. it was the first fave on that account & i was like ?_? -- then we talked, like, twice? and then he blocked me. idk 26-May-20 09:09 PM i really enjoyed his stories & content & the pictures & such he shared 26-May-20 09:09 PM a novel would be absolutely delightful 26-May-20 10:02 PM OK, I don't feel so bad. 26-May-20 10:02 PM I think I was interacting with what I later learned may have been a sock puppet account of his, who chatted with me, blocked me, unblocked me, chatted with me again, blocked me, and the account vanished. I think something similar happened w/ one of his named accounts. 26-May-20 10:13 PM By chatted, I'm referring to conversations in tweet replies. The conversations were entirely friendly, and I tend not to post anything controversial or political on twitter, so all of this came as a complete surprise. I don't think either account friended me. So I'm wondering if I got on someone's Block Together list that he subscribed to. 26-May-20 10:13 PM The excerpt from the novel were brilliant. It described in quite a lot of detail just what it was like to be on the arming party of a weapons effects test. I would totally buy that novel. 27-May-20 10:27 AM https://youtu.be/BTm6JyRpPWw 27-May-20 10:27 AM Advice on how to make coffee... and how not to steal fuel rods. 27-May-20 10:38 AM https://catalog.archives.gov/id/75492147 fun sticker about borrowing tools 27-May-20 10:38 AM https://catalog.archives.gov/id/75492149 also fun tapped down keyboard and mouse 27-May-20 10:38 AM must have been a wild ride for that equipment 27-May-20 10:38 AM https://catalog.archives.gov/id/75492115 totally safe...lets just tape our "event readiness signal" circuitry to the wall 27-May-20 10:45 AM I’m kind of curious why people would pay serious money for it. Fresh Chernobyl RBMK fuel was only enriched to around 2%. Sure that’s a good start, but I don’t see how a potential proliferator could get fuel out at the scale needed to construct a U-235 weapon, nor would it be economical to pay $10k for 1.5 kg, which seems like a lot of premium for only a little enrichment. I’d think anyone with the tech to enrich to weapons grade would be better served by starting from natural uranium. 27-May-20 10:45 AM There’s the possibility that the accident yielded enough neutrons to breed Pu-239 in the fresh fuel in storage. But there’s almost certainly going to be a lot of shielding between the reactor and the fresh fuel storage, so I’d think that would be small. The amount of Pu-239 in the fuel seems like it would be minimal, and it wouldn’t be possible to get anything even close to a critical mass out. 27-May-20 10:45 AM The explanation that it was a test to see if people could do it makes sense. 27-May-20 11:01 AM It ain't proliferators who want it, but collectors. 27-May-20 11:01 AM That's my take anyway. 27-May-20 11:01 AM Ah 1995 27-May-20 11:01 AM I guess somebody read that the rods ware really expensive and decided to branch to that from stealing radiators in the zone 27-May-20 11:04 AM I’ve read stories of back woods deals for plutonium... involving illicit smoke detector sales! 27-May-20 11:04 AM People must not be smart if they think they can use Pu from Soviet industrial smoke detectors to make a weapon. According to Carl Willis, these contain about 1 mg Pu at about 20% Pu-240. 27-May-20 11:22 AM I'd honestly think things like that would be collectors looking for the novelty. 27-May-20 05:58 PM I'd love one for novelty collecting :P 30-May-20 01:11 PM So, on the subject of fusion, and not the fun fusor variety.... 30-May-20 01:11 PM Have any of you followed the research of Gsponer and Hurni into thermonuclear explosives? 30-May-20 01:16 PM Are you referring to their paper on initiating an explosion with an antihydrogen pellet? 30-May-20 01:16 PM Sounds extremely far-fetched, even if the physics works out 30-May-20 01:16 PM They did some reverse engineering on traditional thermonuclear devices. 30-May-20 01:16 PM Including some simulations using software they developed called ISRINEX. 30-May-20 01:35 PM A major arms control problem of fourth generation nuclear weapons is that their development is very closely related to pure scientific research. The chief purpose of the CTBT is to freeze the technology of nuclear weapons as a first step toward general and complete nuclear disarmament. In order to achieve that, it is necessary to implement effective measures of preventive arms control, such as international legally binding restrictions in all relevant areas of research and development, whether they are claimed to be for military or civilian purposes. So they are proposing to stop research into anti-matter generation and storage, inertial confinement fusion, nuclear isomers, magnetic confinement via pinches, just so these technology can't be used to develop their so-called 4th generation nuclear weapons? 30-May-20 01:35 PM They've mentioned all of these technologies as key enablers for their speculative new weapon designs 30-May-20 01:35 PM And their proposed weapon designs are not even good... It misses the point for nuclear weapons in the first place. I can't imagine the cost (probably well into billions of dollars in material alone), just for a 1-100 ton bomb that does nothing significantly better than conventional bombs 01-Jun-20 12:20 PM https://www.youtube.com/watch?v=OfI-XpYAqM0 I'm sure most have seen this video by now 01-Jun-20 12:20 PM I think I'll try making my own ZnS:Ag this way 01-Jun-20 12:20 PM maybe even some boron in there 01-Jun-20 12:24 PM Oh hmmm, darn interesting 01-Jun-20 12:24 PM What’s boron doping do again? 01-Jun-20 12:25 PM not doping, just mixed in there 01-Jun-20 12:25 PM for neutron sensitivity 01-Jun-20 12:25 PM Ah 01-Jun-20 12:25 PM I wish I had any access to Li-6 or at least lithium that wasn’t potentially depleted in it. I’ve read a bit about salicylate neutron scintillators 01-Jun-20 12:28 PM Yeah that would be awesome, but I don't think it would be easy to get for the regular person 01-Jun-20 12:28 PM I haven't heard of those scintillators, gotta look them up!# 01-Jun-20 12:28 PM Some of the characteristic properties of sodium salicylate and p-terphenyl have been studied at a convenient incident wavelength of 253.7 nm. 01-Jun-20 12:28 PM oh, fun 01-Jun-20 01:32 PM huh neat 04-Jun-20 08:22 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-24228.png 04-Jun-20 08:22 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-67AC9.png 04-Jun-20 08:22 AM big neutron detector just got its preamps 04-Jun-20 09:13 AM Pretty.... 05-Jun-20 03:07 PM TIL: 05-Jun-20 03:07 PM https://www.berkeleynucleonics.com/cerium-bromide 05-Jun-20 03:07 PM pretty damn bright at 60 k photons per MeV, downside is emission at 380 nm 06-Jun-20 01:47 PM I'm still cranky with myself I never made the time to go visit their facility before COVID hit. They're so happy to bring pretty much everything to my office. 06-Jun-20 01:50 PM ohhh! 06-Jun-20 01:50 PM can you organize samples? 06-Jun-20 01:52 PM Not free ones, but they will let fondle the toys. 06-Jun-20 01:55 PM :> 06-Jun-20 11:23 PM i miss fondling toys :C 06-Jun-20 11:23 PM the SV ham swap meet can't come back soon enough 07-Jun-20 07:59 AM I’m still a bit disappointed I haven’t gone to anything like that yet 07-Jun-20 07:31 PM Ok, I may be going out on a limb here, but I’m thinking there’s a slight chance this end window Geiger tube might be faulty.... 07-Jun-20 07:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-D9B28.jpg 08-Jun-20 01:06 AM That's a weird looking air proportional counter 09-Jun-20 11:48 AM Hehe yeah 09-Jun-20 11:48 AM Did the inside oxidize? 09-Jun-20 11:48 AM Or is that some kind of coating on the interior of the tube? 09-Jun-20 11:49 AM don't know about any kind of coating 09-Jun-20 11:49 AM might actually be rust as the tubes tend to be iron without any protective layer 09-Jun-20 11:50 AM do those have a halogen component of the gas fill? could be oxidation from that 09-Jun-20 11:53 AM hmm good question 09-Jun-20 11:53 AM GMs often have halogens inside, but I'm not sure why the cathode doesn't just getter that out with time 09-Jun-20 11:59 AM the research I've done about that mostly involves various passivation processes but that was not an end window tube 09-Jun-20 11:59 AM chrome plating also worked which seemed a bit surprising 15-Jun-20 01:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E0BA6.png 15-Jun-20 01:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-9F862.png 15-Jun-20 01:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F9A60.png 15-Jun-20 01:28 AM I love those "Manufactured with Pride" stickers from canberra 15-Jun-20 01:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-25728.png 15-Jun-20 01:28 AM but they glued a heatsink to the chip :v 15-Jun-20 04:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200615_133553-31C3E.jpg 15-Jun-20 04:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200615_133658-4B2BF.jpg 15-Jun-20 04:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200615_133821-66E64.jpg 15-Jun-20 04:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200615_133829-7469C.jpg 15-Jun-20 04:42 AM well, well, well 15-Jun-20 11:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/InkedIMG_20200615_201223_LI-26711.jpg 15-Jun-20 11:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200615_201320-346D5.jpg 15-Jun-20 11:25 AM ...what? 15-Jun-20 11:25 AM fibre coupled scintillator 15-Jun-20 11:25 AM tiny scintillator on fiber? 15-Jun-20 11:25 AM ohh 15-Jun-20 11:25 AM neat! 15-Jun-20 11:26 AM not sure what the specific application is 15-Jun-20 11:27 AM that size and the Be window suggest XRF or the likes 15-Jun-20 11:27 AM low energy stuff 15-Jun-20 11:27 AM fiber coupled instead of just using a small pmt suggests strong magnetic fields 15-Jun-20 11:31 AM the window is made out of Be? Good to know 15-Jun-20 11:31 AM it very much looks like it 15-Jun-20 11:31 AM and small scintillators are for low energy, that needs Be ^^ 15-Jun-20 11:32 AM fiber coupled instead of just using a small pmt suggests strong magnetic fields @GigaSquirrel that would fit very well 15-Jun-20 11:33 AM do you know (can say) where it came from? 15-Jun-20 11:57 AM It's out of an accelerator complex. Not even sure if it works. 15-Jun-20 11:57 AM yeah but I mean what experiment etc ^^ 15-Jun-20 11:57 AM also I am pretty sure I have everything here to test it if you're interested 15-Jun-20 12:01 PM me too. I'll try to hook the PMT up und after that I send it you? 15-Jun-20 12:03 PM well if you don't need it... 15-Jun-20 12:29 PM Too late 15-Jun-20 12:30 PM found a use for it? 16-Jun-20 03:52 AM Well 16-Jun-20 03:52 AM https://www.ost-photonics.com/product-category/scintillation-crystal-2/ 16-Jun-20 03:52 AM I just found this site 16-Jun-20 03:52 AM NaI is cheaper than expected tbh 16-Jun-20 03:52 AM but I have no idea how they compare 16-Jun-20 03:52 AM I am still waiting for a quote from berkley nucleonics for some scintillators 17-Jun-20 01:34 PM wellp 17-Jun-20 01:34 PM I got a quote 17-Jun-20 01:34 PM I can't afford it 17-Jun-20 02:46 PM Have you filed for bankruptcy yet? 17-Jun-20 02:48 PM gonna sell the hose to get a sample 17-Jun-20 02:48 PM Hose or house 17-Jun-20 02:48 PM the one tha brings more money 17-Jun-20 02:48 PM sadly I'm not that good looking 17-Jun-20 02:48 PM I hope that's some damn expensive hose youve got there then 17-Jun-20 02:48 PM I contacted a company in china earlier this spring about LaBr3 scintillators but they didn't have any material on hand 17-Jun-20 02:49 PM I just contacted a few on alibaba, also asked scionix 17-Jun-20 02:49 PM apparently berkley gets their crystals from scionix, and resell them, at a margain ofc 17-Jun-20 02:49 PM I didn't expect them to be that expensive tbh :v 17-Jun-20 02:51 PM Can you give an order of magnitude for cost? 17-Jun-20 02:52 PM I was quoted ~ 2k for a 25x25 mm crystal 17-Jun-20 02:52 PM Yikes 17-Jun-20 02:52 PM yep 17-Jun-20 02:52 PM for LBC, not LaBr3 17-Jun-20 02:52 PM I'm not sure how much that adds, but it can't be that much 17-Jun-20 02:54 PM I wish that organic inorganic hybrid semiconductor I read about was legal to make 17-Jun-20 02:55 PM the what now? 17-Jun-20 02:55 PM also, I've considered CZT, but that's not exactly cheap either 17-Jun-20 02:58 PM I think it was MAPbI3 17-Jun-20 02:58 PM It looked like it might have been somewhere between LaBr3 and NaI 17-Jun-20 02:59 PM hmm 17-Jun-20 02:59 PM the fact that is has lead and iodine sounds promising 17-Jun-20 03:01 PM The issue I think was that one of the solvents used in most of the papers I found was debatably legal 17-Jun-20 03:01 PM at best 17-Jun-20 03:02 PM ah, I see 17-Jun-20 03:02 PM well, I thought about making my own crystals, but I am not sure about growing my own semiconductors 17-Jun-20 03:02 PM I found some promising stuff about SrI2 some time ago, but I don't remember if it was the pure stuff or (Eu) 17-Jun-20 03:04 PM These were supposedly able to be grown in solution but the solvent was a big issue 17-Jun-20 03:25 PM https://www.hamamatsu.com/eu/en/product/type/C10940-53/index.html 17-Jun-20 03:25 PM Has anyone an idea what the price tag could be? 17-Jun-20 11:35 PM knowing hamamatsu I'm guessing 2-300? 18-Jun-20 04:39 AM ok then 18-Jun-20 04:39 AM something self build it is. 18-Jun-20 05:38 AM yep :D 18-Jun-20 05:38 AM ccfl inverters are reasonably linear 18-Jun-20 12:59 PM been thinking about air quality sensors a lot lately and i stumbled across a neat thing https://metone.com/products/bam-1022/ 18-Jun-20 12:59 PM it uses an exempt quantity (!) of C14 as a beta source to measure air particulate occlusion on a continuous tape 18-Jun-20 12:59 PM at least, exempt in the US (65μCi ±15) so .. theoretically.. DIYable? 18-Jun-20 12:59 PM probably a tradeoff to be made between readout speed and source strength + detector efficiency too 18-Jun-20 01:03 PM Oh wow! I almost feel like the detector would be the easiest part. The continuous tape air filter sounds like it might be harder 18-Jun-20 01:04 PM yeah, haha 18-Jun-20 01:05 PM I feel like if you had a proportional detector on the backside you could have it set up to subtract out alpha particles from radon and decay products too 18-Jun-20 01:05 PM And I guess it would double as a radioactive air monitor? If readings ever went negative? 18-Jun-20 01:06 PM i imagine it'd have to be really spicy outside for that, heh 18-Jun-20 02:31 PM Maybe 18-Jun-20 02:31 PM probably 19-Jun-20 02:38 AM well 19-Jun-20 02:38 AM https://doi.org/10.1016/j.jcrysgro.2005.02.034 19-Jun-20 02:38 AM this looks hella promising 19-Jun-20 02:38 AM LaCl3 is really cheap 19-Jun-20 02:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-15AFC.png 19-Jun-20 02:38 AM quoted energy resolution is ~3.1% from what I can find 19-Jun-20 02:38 AM you can also dope it with ~10% Ce(III), but I can't really find what that does 20-Jun-20 12:08 PM @Eric this might suffice?? https://www.steminc.com/PZT/en/multi-layer-piezo-transformer-55-khz-6w 20-Jun-20 12:18 PM Context? 20-Jun-20 12:18 PM Ok. Just had to think about it. 20-Jun-20 12:20 PM as a substitute to the hamamatsu hvps 20-Jun-20 12:20 PM but still, ccfl inverters ^^ 20-Jun-20 12:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/large_anticompton-geconverteerd-DF7F0.pdf 20-Jun-20 12:38 PM Hadn't thought that NaI(Tl) is so machinable 20-Jun-20 12:44 PM or that it can even be grown that big 20-Jun-20 03:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E8C02.png 20-Jun-20 03:03 PM and I was wondering why that detector didn't give any signal 20-Jun-20 03:03 PM Is there glass there? 20-Jun-20 03:04 PM I am not sure 20-Jun-20 03:04 PM I don't think they glued the pmt to the NaI, but I can't see any glass 20-Jun-20 03:11 PM there's some goopy glue on there, between the pmt (and air around it!) and the crystal 20-Jun-20 03:11 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D5739.png 20-Jun-20 03:11 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-FEEC4.png 20-Jun-20 03:17 PM Yikes 20-Jun-20 03:18 PM yep 20-Jun-20 03:18 PM I'd love to do a cross section to see how deep the yellow goes 20-Jun-20 03:18 PM but I seem to have misplaced my dry oil lubed crystal saw 21-Jun-20 07:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200621_155814-EE385.jpg 21-Jun-20 07:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200621_155905-6D958.jpg 21-Jun-20 07:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200621_160117-D1F7D.jpg 21-Jun-20 07:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200621_160708-59FEA.jpg 21-Jun-20 07:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200621_161839-A6C46.jpg 21-Jun-20 07:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200621_162857-4B8A1.jpg 21-Jun-20 07:31 AM wrapped up like a christmas present 21-Jun-20 07:32 AM How hydroscopic is that stuff? 21-Jun-20 07:32 AM diode and crystal are not exactly well matched, both in size and wavelength, but it should be good enough ™️ 21-Jun-20 07:32 AM not really / not at all 21-Jun-20 07:33 AM ok 21-Jun-20 07:33 AM it's CsI pure, not :Na or :Tl 21-Jun-20 07:33 AM Na is very hydroscopic, Tl somewhat 21-Jun-20 07:33 AM sweet 21-Jun-20 07:33 AM Yeah was thinking about NaI 21-Jun-20 07:33 AM NaI is really hydroscopic 21-Jun-20 08:03 AM diode and crystal are not exactly well matched, both in size and wavelength, but it should be good enough ™️ @GigaSquirrel Zero output 21-Jun-20 08:03 AM I need another diode 21-Jun-20 08:03 AM PIN and UV sensitive 21-Jun-20 08:03 AM ideally I'd get another detector but that's a different story 21-Jun-20 08:08 AM Have you considered ready-made x-ray detectors from Hamamatsu that's also CsI coupled directly to the same PIN diode? 21-Jun-20 08:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-25043.png 21-Jun-20 08:09 AM that looks like a dessert from /r/wewantplates 21-Jun-20 08:09 AM They are not that expensive and there are Chinese versions that goes down to $50 or so 21-Jun-20 08:09 AM This one's Hamamatsu S8559 21-Jun-20 08:09 AM I've got two 21-Jun-20 08:10 AM that's the point, the detector on those is CsI(Tl) 21-Jun-20 08:10 AM way brighter and in the red region 21-Jun-20 08:10 AM mine is like 2 photons per keV and ~380 nm max 21-Jun-20 08:10 AM I have not found any pricing for those, do you have a link? 21-Jun-20 08:11 AM So... what's the advantage of pure CsI over this again? 21-Jun-20 08:12 AM it was cheap on ebay 21-Jun-20 08:12 AM I'd love some CsI(Tl) 21-Jun-20 08:14 AM I'm digging up the link now. They're used for densitometers to measure x-ray transmission through thin stuff 21-Jun-20 08:14 AM Okay, I could only find a TaoBao link (Chinese version of eBay): https://item.taobao.com/item.htm?spm=a1z09.2.0.0.49412e8dzhnPt0&id=566602246173&_u=ljd09ogf6a5 21-Jun-20 08:14 AM But they offer a genuine S8559 and a cheap version of the S8193. The S8559 has tripled in price since I bought it 21-Jun-20 08:14 AM And the same thing on aliexpress: https://www.aliexpress.com/item/32898757182.html 21-Jun-20 08:26 AM awesome, thank you! 21-Jun-20 08:27 AM So apparently you can get really cheap gadox screens: https://www.ebay.com/itm/LOT-of-2-Green-Rare-Earth-RE-400-Speed-X-ray-Cassette-Film-Imaging-8x10-10x12/323971780727 21-Jun-20 08:27 AM I wonder how thick the scintillator in it actually is... When used for neutron detection, gadox has higher capture efficiency than a lot of the Li-6 based stuff that's impossible to get, but I believe the actual light yield is lower 21-Jun-20 08:28 AM Nice 21-Jun-20 08:28 AM I have one ancient phosphor+1cm leadglass in a wooden frame here somewhere 21-Jun-20 08:28 AM But never had anything to light it up with, so yet to see how well that thing works 21-Jun-20 08:30 AM hows gamma rejection on those? 21-Jun-20 08:30 AM Really bad for soft x-rays 21-Jun-20 08:30 AM yeah I figured 21-Jun-20 08:30 AM but some high Z low capture material in front should do the trick 21-Jun-20 08:31 AM Yeah you'd need to design some shielding for soft x-rays, it's not that bad once you get into the MeV gammas 21-Jun-20 08:31 AM Also, the decay time is apparently really long 21-Jun-20 08:31 AM So for a pulsed source, you can't really do time of flight 21-Jun-20 09:07 AM Can’t you pulse the ToF? 21-Jun-20 09:07 AM #radiation is my #black-magic 21-Jun-20 09:19 AM To do ToF and get a spectrum for neutrons, you'd need to distinguish pulses of light from neutrons of different energies arriving at most a few microseconds away from each other 21-Jun-20 09:19 AM But the long afterglow just means it will all get smeared out 21-Jun-20 09:23 AM I'm sure with some fancy electrode junk you can filter it, similar to a quadropole mass spec... 21-Jun-20 09:24 AM Is that a channel or a joke 21-Jun-20 09:28 AM the joke would be that it's a channel that you access with the konami code 21-Jun-20 09:50 AM Oh how I wish there are some black magic electrode stuff that can turn a slow scintillator with afterglow into a fast scintillator 21-Jun-20 11:00 AM There's so much fancy gating stuff 21-Jun-20 11:07 AM Well I think the fundamental issue is with the scintillation process. I don't think there's any amplification/light processing techniques that sits after the scintillator which can overcome just how slow these inorganic crystals are 21-Jun-20 11:07 AM It seems to me there's always a trade-off between price, light yield and speed 21-Jun-20 11:07 AM Choose two out of three 21-Jun-20 11:07 AM I had hoped that something like the NOL scintillators described here may become quite affordable (given CERN just ordered a massive amount of them): https://www.nature.com/articles/srep06549 21-Jun-20 11:07 AM But I underestimated just how much funding CERN have for detector development, they are around 10 to 50 times more expensive than polystyrene-based scintillators 21-Jun-20 11:54 AM Are these crystals phosphorescent rather than fluorescent then? I don't really know much of anything about scintillators, but fluorescent should be on the order of magnitude of nanoseconds, so I don't see why microsecond differences would be an issue in that case 21-Jun-20 11:55 AM These are phosphorescent 21-Jun-20 11:55 AM https://en.wikipedia.org/wiki/Activator_(phosphor) 21-Jun-20 11:56 AM Granted I think it's order of magnitude hundreds of nanoseconds rather than like 3, but still 21-Jun-20 11:57 AM Inorganic scintillators are generally quite a bit slower than organic ones, something about their chemistry that I don't fully understand. But even if we are talking on the order of a few hundred nanoseconds to a microsecond afterglow, the neutron energy resolution would be so bad that might not be even useful for thermal neutrons 21-Jun-20 11:57 AM Again, I'm mainly interested in ToF for neutron energy spectroscopy 21-Jun-20 11:57 AM There might be some time-dependent analysis that you can do to compensate for the effect of the slow afterglow component of the scintillation light 21-Jun-20 12:02 PM Nah, that's a design choice. They dope it in such a way that they have long emission. It looks like I was overestimating cameras and it's not reasonable to take data that fast though 21-Jun-20 12:05 PM So you still trade off sensitivity/light yield for speed. For practical ToF of neutrons into the epithermal range (up to hundreds of keVs), then you definitely need time resolution on the order of a few nanoseconds 21-Jun-20 12:05 PM But it looks like the slow afterglow light is emitted from a different mechanism than the fast scintillation component. According to that Wiki article: Those holes and electrons are captured successively by impurity centers exciting certain metastable states not accessible to the excitons. The delayed de-excitation of those metastable impurity states, slowed by reliance on the low-probability forbidden mechanism, again results in light emission (slow component). So perhaps their magnitude would be very different, and it might be possible to still detect individual fast pulses over the afterglow? 21-Jun-20 12:10 PM You can't say in general there. Depends a lot on the actual scintillator/regime you're in. I'm pretty confident there is a way, but it's probably not worth it because it'd be convoluted/expensive/likely to break if you sneeze on it 21-Jun-20 01:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/EbDV_h_WoAApQfv-B1EC4.png 21-Jun-20 02:41 PM @GigaSquirrel how do you get apart those square Bicron scints? 21-Jun-20 02:41 PM Is the crystal supposedly hermetically sealed, or does opening the square metal bit break things? 21-Jun-20 02:42 PM Yes 21-Jun-20 02:42 PM Sometimes they are sometimes they aren’t if I remember correctly 21-Jun-20 02:42 PM I’ve asked around a few places and I got two different answers so I haven’t done it personally yet 21-Jun-20 02:44 PM I'm a bit confused with mine, it looks like the cystal itself is open now, but it isn't nearly as hygroscopic as I thought 21-Jun-20 02:44 PM the last NaI I took apart literally liquefied 21-Jun-20 02:46 PM Yellow crystal = serious water damage. 21-Jun-20 02:47 PM yeah, I know 21-Jun-20 02:47 PM but that's long term water damage 21-Jun-20 02:47 PM quick water damage is just the crystal dissolving 21-Jun-20 02:53 PM Actually I think my square Bicron works, it’s a cylindrical Thermo “smart” probe that is presumably dead. 21-Jun-20 03:20 PM I measured my NaI today, it does 6.7% at 609 keV, I wonder how that differs to 662 keV 24-Jun-20 03:12 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200624_121147_284-B2A35.jpg 24-Jun-20 07:01 AM Oh my. 24-Jun-20 07:37 AM Wow 24-Jun-20 11:22 AM But isn’t that going to get destroyed due to moisture? 24-Jun-20 11:42 AM Very low humidity room and the crystal will be cut down so some surface damage is acceptable? 24-Jun-20 02:36 PM @Epilogis from #general, since it's technically radiation-related -- PMT is short for 'photomultiplier'; they are very sensitive light detecting vacuum tubes (down to single photons) that are used for radiation detection when coupled to a scintillating crystal (like that enormous NaI(Tl) behemoth above.. they're usually a bit smaller though :D) 24-Jun-20 02:36 PM a PMT base, like my DS-11, is just a connector used to supply a distribution of operating voltages to the PMT and also to couple a useful signal out of it. I also can't find any information on the DS-11 specifically; it's probably like 60 or 70 years old at this point 24-Jun-20 02:36 PM there's some pictures in this thread https://twitter.com/profanegeometry/status/1275756348408344576?s=19 24-Jun-20 02:36 PM PMT's the black+brown thing, base is the silver thing, the box is a charge sensitive amplifier. the business end of the PMT containing the scintillating crystal (also NaI(Tl)) is the taped-over lump at the top 24-Jun-20 02:36 PM i have no clue what became of the distinctively-named Technical Measurement Corp 24-Jun-20 10:27 PM The one pmt i have it tiny, like the size of my smallest finger 25-Jun-20 01:28 AM smol 25-Jun-20 01:28 AM cute 25-Jun-20 08:26 AM @qualia Oh okay thanks for the explanation! makes a lot more sense now 25-Jun-20 12:59 PM Im playing around with a new setup and keep getting weird symmetric pulse shapes 25-Jun-20 12:59 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-5F843.jpg 25-Jun-20 01:03 PM that looks like some aliasing effect of your soundcard, because the Signal is above nominal frequency of your Hardware 25-Jun-20 01:04 PM I feel like I sorta follow, though I’m not sure what to do about that 25-Jun-20 01:06 PM question is if it makes anything worse 25-Jun-20 01:06 PM Like if it's even a Problem 25-Jun-20 01:09 PM I’m still figuring this setup out 25-Jun-20 01:09 PM Thanks 25-Jun-20 01:16 PM any info about the Setup? ^^ 25-Jun-20 01:21 PM The small square bicron scintillator, RH electronics preamp and switching between the power supply I showed a week or two ago and one of my detectors for HV 25-Jun-20 01:21 PM Nothing fancy just trying to see if I can get anything 25-Jun-20 01:23 PM cool, good luck! 25-Jun-20 01:23 PM also, I got better results with becqmoni 25-Jun-20 01:24 PM Thanks, I’ll try that one 25-Jun-20 01:24 PM And whenever I finally get the board made for the alpha spectrometer that I have parts for I there’s software specifically for that 25-Jun-20 01:25 PM ohh, alphaspec is fun 25-Jun-20 01:25 PM what sensor? 25-Jun-20 01:32 PM Decapped bpx61 photodiode 25-Jun-20 01:33 PM ahh, hehe 25-Jun-20 01:33 PM Oliver Keller likes this idea 25-Jun-20 01:33 PM alphaspec itself is quite easy as far as semiconductor stuff goes 25-Jun-20 01:33 PM the main issue is sample preparation 25-Jun-20 01:34 PM Yeah that’s going to be interesting 25-Jun-20 01:36 PM a simple test is electrostatic radon collection, that gives great, sharp peaks 25-Jun-20 01:36 PM I’ve got an air ionizer module out of an old ac unit I’m planning to wire up 25-Jun-20 01:37 PM I used some Ra ore and like -1 kV for that 25-Jun-20 01:37 PM let it run over night and I got a few 100 cps 25-Jun-20 01:37 PM https://youtu.be/wp1xCdZWw4o 25-Jun-20 01:39 PM Might hook an air pump and filter out of the box of radioactive rock 25-Jun-20 01:41 PM from what I gathered the electrostatic part is important for the thin layer 25-Jun-20 01:41 PM Ah, makes sense 26-Jun-20 01:55 PM https://twitter.com/SwiftOnSecurity/status/743267898529980416 26-Jun-20 06:14 PM Just how restricted is MCNP? 26-Jun-20 06:14 PM Is it just export restricted? 26-Jun-20 06:15 PM It helps to have someone sponsor you getting a license 26-Jun-20 06:15 PM The ORNL site lists it as covered under Part 810. And they seem to want to charge you $1000. 26-Jun-20 06:16 PM Hm, I don’t remember hearing anything about cost 26-Jun-20 06:16 PM Coworker who has one says it didn’t cost anything 26-Jun-20 06:18 PM https://rsicc.ornl.gov/CostRecovery.aspx 26-Jun-20 06:20 PM Hmm 26-Jun-20 06:20 PM Hadn’t seen that before 26-Jun-20 06:24 PM I’m wondering under what basis it is restricted. I don’t think it could be classified. I know ITAR imposes all sorts of obstacles to foreign nationals. I understand export control, but what about for ordinary citizens in the US? 26-Jun-20 06:25 PM It’s not classified for sure 26-Jun-20 06:25 PM I’m think it’s just ensuring export control 26-Jun-20 06:33 PM Interesting. Katie was joking about it on Twitter, and the thread there seemed to imply that it was hard to get, legit grad students were getting denied, etc. 26-Jun-20 06:35 PM Weird, I guess it might depend on the application submitted? 26-Jun-20 06:37 PM That’s what I’m trying to understand.... On what basis is it being restricted? 26-Jun-20 06:40 PM I can ask 26-Jun-20 06:40 PM It sounds like there’s someone who is making a subjective judgment about who has a legitimate need and who doesn’t. But that doesn’t seem very... government-like. If it is classified, then of course, you have to have that security clearance and a need to know. But it isn’t. Export control shouldn’t apply to citizens within the US. 26-Jun-20 06:43 PM So as for the cost recovery part they obtained the license before it 26-Jun-20 06:43 PM But it is export control without a doubt 26-Jun-20 06:44 PM That part, I understand.... 26-Jun-20 06:44 PM It just seems that this is in a weird grey area.... like it’s just physics, and it isn’t classified, but there’s still limitations.... 26-Jun-20 06:45 PM It’s the implementation that’s restricted 26-Jun-20 06:45 PM So that’s part of it 26-Jun-20 06:45 PM I think because you can use it to predict explosive yields of some critical assemblies 26-Jun-20 06:45 PM I can send you his email as well. 26-Jun-20 06:49 PM This is just idle curiosity on my part. No need to bug anyone. 26-Jun-20 06:49 PM Ok then 26-Jun-20 06:52 PM As soon as Katie mentioned it, I wondered if it would be possible to simulate what would happen with the “Science Made Stupid” “reactor”. 26-Jun-20 06:52 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-1597D.png 26-Jun-20 06:54 PM Without a doubt it could be simulated 26-Jun-20 06:59 PM I’ve also heard of something called ISRINEX. 26-Jun-20 06:59 PM Gsponer used it specifically to simulate supposed thermonuclear weapon designs, attempting to reverse engineer Ivy Mike from openly available data. 26-Jun-20 07:03 PM Can’t say I’ve heard of that one 26-Jun-20 07:23 PM https://cryptome.org/2014/06/wmd-4th-gen-quest.pdf 26-Jun-20 07:49 PM You can't get the MCNP source code or even a local executable without a sponsor or some form of security clearance 26-Jun-20 07:49 PM The most you can get is probably just a cloud copy, which is incredibly frustrating to use 26-Jun-20 07:50 PM That's what I was told as well about needing a sponsor 26-Jun-20 07:50 PM You don't get errors or feedback for ages sometimes 26-Jun-20 07:50 PM Also, all of your input decks are stored by RSICC 26-Jun-20 07:50 PM And may be reviewed 26-Jun-20 07:50 PM If they determine you are using it for purposes other than the one you're telling them, they can and do terminate people's access permenantly 26-Jun-20 07:50 PM I'd highly recommend OpenMC for neutron and reactor stuff, and Geant4 for other high energy physics 26-Jun-20 08:01 PM I'm starting to appreciate the sheer information density of MCNP input decks though 26-Jun-20 08:01 PM We might be able to trace its lineage back to the days when they have to fit these on physical cards. 26-Jun-20 08:02 PM I'm pretty sure you can 26-Jun-20 08:03 PM Some of them are clearly modern, like some general macrobodies definition, I'd like to see the source code for that. They've recently extended it in MCNP6 26-Jun-20 08:03 PM I'm writing some python class for essentially macrobodies in OpenMC, and it's an absolute pita 26-Jun-20 08:03 PM Surprisingly simple geometries like wedges and polygons are much more complex to implement than higher order surfaces like ellipsoids and toroids 26-Jun-20 08:03 PM And some geometry which requires a 4th order equation in Cartesian coordinates is just impossible to model in OpenMC at the moment, unless you use the CAD import functionality 26-Jun-20 08:03 PM I don't understand why someone at Oakridge haven't released a Python or C++ API for MCNP yet (subject to the same approval process as obtaining the MCNP executable), for both input generation and output data analysis 26-Jun-20 08:03 PM Covering the most basic functions 26-Jun-20 08:03 PM As it is now every serious user must write their own little "search and replace" script to run MCNP parametrically, and existing libraries like pyNE is not powerful enough because it's restricted by its public nature 26-Jun-20 08:03 PM Which is funny because you can literally go on Google and download a copy of the restricted volume of the MCNP6.2 manual 26-Jun-20 08:38 PM Actually, a really basic version of this C++ API already kinda sorta exists: https://mcnp.lanl.gov/pdf_files/la-ur-17-21779.pdf 26-Jun-20 08:38 PM It is only used for extracting tally results though 26-Jun-20 10:07 PM You can also get copies of MCNP if it is involved in course work, but you are obligated to destroy it afterwards :) 27-Jun-20 04:42 AM I guess I’m trying to understand what is being restricted and how.... 27-Jun-20 04:42 AM It seems clear that MCNP is dual use, in that if you can simulate a reactor, you can simulate a bomb. 27-Jun-20 04:42 AM But is there something inherently illegal about someone without a Q clearance using freely available physics knowledge and experimental data to create and run their own simulations? 27-Jun-20 04:42 AM I would think not.... I imagine ITAR might apply to its export, but if done by US citizens in the US, is it a problem? 27-Jun-20 04:42 AM Access to fissionable material is the primary safeguard against proliferation. And I imagine such a model probably couldn’t be complete because some parameters can only be determined via weapons tests or subcritical tests, and those results would be classified. 27-Jun-20 04:42 AM I’m aware of born secrets doctrine, which may technically be on the books, but has been void since the government dropped the case against The Progressive. 27-Jun-20 04:42 AM This book https://www.amazon.com/Physics-Manhattan-Project-Bruce-Cameron/dp/3642147089 describes atomic bomb design and includes spreadsheets with numerical models. 27-Jun-20 04:42 AM So I’m trying to understand by what authority can the government author code and then selectively make it available based on vetting of a person’s needs for it without resorting to classification. 27-Jun-20 04:42 AM Could someone FOIA the code? 27-Jun-20 04:42 AM It sounds like there is some legal or regulatory structure at work here that I’m not aware of.... It struck me as odd that Katie would assert it was illegal to use this code to design a nuclear reactor at home. 27-Jun-20 05:28 AM Interesting, this doc on the IAEA website says MCNP is public domain. https://inis.iaea.org/collection/NCLCollectionStore/_Public/16/046/16046171.pdf?r=1&r=1 27-Jun-20 05:28 AM Also, if this is trending too far afield from radiation, I’m happy to move this discussion to #off-topic-thats-sometimes-on-topic 27-Jun-20 06:03 AM Not knowing the whole potential situation but generally ITAR rules apply to US citizens too. There were things made at the other company we could not sell to say Iran or others. The owner of another competitor company actually did go to jail over breaking those laws. 27-Jun-20 06:15 AM My understanding is that ITAR restricts export. Obviously, selling to Iran is a big deal, as is public posting of information on the internet. I’m talking about a scenario where US citizens exchange information with other US citizens within the US. 27-Jun-20 10:47 AM https://www.ecfr.gov/cgi-bin/text-idx?SID=62ed1773ffc6bff44752fc9533265f60&mc=true&node=pt10.4.810&rgn=div5 27-Jun-20 10:47 AM Here are the federal codes that governs the export restriction of MCNP and SCALE. As you can see it is only applicable to foreign citizens, I am not aware of any other federal codes that explicitly restrict access to these codes for US citizens 27-Jun-20 10:47 AM To US citizens, these codes are indeed in the public domain, you might have to pay the $1000 to get it though. These export control considerations means RSICC can't just put up a public download link for the source code of MCNP, and everyone (including US citizens) will need their identity approved before getting access to the code 27-Jun-20 10:47 AM To enforce those export restrictions, the only option is for RSICC to remain the sole distributor of MCNP, so that'll deny any FOIA requests and it'll be impossible for a US citizen to just give a copy to another US citizen 27-Jun-20 01:05 PM This part makes sense. But it also seems to disagree with what I’ve heard, e.g. that the feds evaluate the purpose for which these tools are used, it’s difficult to get them, it is advisable to have a sponsor, one can’t keep them after the class they are used for is over, and they’re moving users to a cloud that they run so that the uses of these tools can be audited against the stated purposes. 27-Jun-20 01:11 PM Everything you've heard there is quite correct. While I still have my MCNP disk from my masters degree work, which I found while cleaning, the very first thing that the program will ask to do after installation is to ping the mothership. It won't let you do anything without that ping to verify. What I will be doing is the thing I should have done 12 years ago: toss that disk in an envelope back to where it came from. 27-Jun-20 01:18 PM Ok, but that seems like the opposite of public domain to US citizens with export control as @Mason_Yu seemed to imply. 27-Jun-20 01:31 PM Sorry, that's probably a bad use of the word "public domain", because it's not completely free of copyright restrictions. UT-Battelle, LLC (basically Oakridge National Laboratory) still owns the copyright to reproduce, sublicense and modify the software. Or else those federal codes cannot possibly be enforced. What I mean is that, as a US citizen (the public), there is nothing legally stopping you from requesting the code for non-export controlled purposes and they should give access to the code to you 27-Jun-20 01:31 PM More terms and conditions apply of course, and you'll receive a whole list of them when your request goes through on RSICC. Chief among which is that you can't just give your access code to another person without telling RSICC, and you may have to pay into the cost recovery program without a sponsor 27-Jun-20 01:31 PM RSICC and Oakridge has the incentive to make it as difficult as possible for people in the public to get access to MCNP, and I personally believe that's why they have no great motivation to modernize it and make it more user-friendly 27-Jun-20 01:31 PM So I think codes like OpenMC has great potential and should be given more attention. It is only going to get better over time and it is much easier to use than MCNP 27-Jun-20 01:51 PM Interesting. One of their examples involves importing the Utah Teapot and heating it with a neutron source. 27-Jun-20 01:52 PM Now try doing that in MCNP 28-Jun-20 07:06 AM https://mag.uchicago.edu/science-medicine/homemade-breeder-reactor 28-Jun-20 07:06 AM Fun story: Fred Niell was in my UChicago undergrad physics class. 28-Jun-20 07:06 AM I wasn’t at the Scav Hunt when it happened, but I remember walking on campus and seeing Fred with the NIM crate, I think afterwards when they were cleaning up. I immediately recognized it and asked him about it. 28-Jun-20 07:20 AM That said, something seems wrong with the description. I’m wondering if he is being intentionally vague. 28-Jun-20 07:20 AM Ra + C film does not produce thermal neutrons. I’d think there needs to be a Be target in there, either a foil or powder mixed with Ra paint. 28-Jun-20 07:20 AM I can understand if he might want to avoid mentioning Be. 28-Jun-20 07:20 AM I imagine he could have demonstrated Th232 + n -> Th233 B- -> Pa233 B- -> U233. 28-Jun-20 07:20 AM Pa233 has a 27 day half life, so I imagine that was a limiting factor getting to producing U233 in the space of a few days. 28-Jun-20 07:40 AM But the statements that neutron capture continued, and he bred U235 and Pu239 make no sense to me.... given that he was producing U233 on the order of thousands of atoms, the probability of those atoms capturing neutrons seems small. He’d need massive neutron flux if he wanted to guarantee a significant number of those did capture a neutron, but if he had that, the Th232 would be capturing neutrons too.... 28-Jun-20 07:40 AM I could see him breeding Pu239 if he also had a U238 target. 29-Jun-20 04:06 PM This is why we are VERY EXPLICIT about what targets are permitted with our researchers. We have a broad scope license with some pretty impressive inventory limits thanks to being inheritors of the Manhattan Project, but NRC & DOE get very cranky when you start making SNM without prior permission. 29-Jun-20 06:20 PM I am picturing Hans Blix from team America. We are here to count your neutrons. I know he was IAEA and not US but still. That was a funny scene. 30-Jun-20 10:18 AM what a movie that was 30-Jun-20 10:18 AM why is MCNP's cloud version hard(er) to use? when i first heard about it i was kinda excited, 'cos it seemed like it would (or could) be an easier route of access for a hobbyist, given they're presumably going to record & scrutinize literally everything i do with it 30-Jun-20 10:30 AM really should just hunker down and put the effort into OpenMC for trying to model detectors + shielding + etc, probably liable to turn up some bug/feature reports along the way 30-Jun-20 11:28 AM It's harder to use because you don't always get immediate feedback 30-Jun-20 11:28 AM And if you want to model any complex geometry, it will just take ages to make everything right in MCNP 30-Jun-20 11:28 AM Because the input decks have really poor human readability, you rely on error messages and debugging tools like the geometry plotter, which you also need to access via the cloud 30-Jun-20 11:28 AM I think Geant4 does a better job with modeling scintillation and semiconductor detectors, but if you want something quick and easy to set up, then OpenMC is easier 30-Jun-20 11:40 AM I'm trying to get the optical photon transport function in Geant4 working 30-Jun-20 11:40 AM But I also need mesh import from CAD to work before that, which is probably a bigger challenge, because I'm trying to mix CAD with traditional constructive solid geometry surfaces and volumes 30-Jun-20 11:40 AM I can definitely appreciate why people are treating G4 as a toolkit, instead of a full blown simulation software that's meant for a broad audience in the engineering and physics world 30-Jun-20 11:40 AM G4Beamline and BDSIM is based on the G4 toolkit, but they are much easier to use 30-Jun-20 11:40 AM On the same level as OpenMC 30-Jun-20 11:40 AM But those G4 derived software are really only meant for pretty specific applications, mostly in accelerator and beamline design 30-Jun-20 11:40 AM It is possible to use them for unorthodox purposes, but many fancy features from G4 are not available, like optical photon transport for example 01-Jul-20 10:35 AM openMC requires you to use the cloud? 01-Jul-20 10:35 AM eww 01-Jul-20 11:17 AM I think that is referring to the cloud version of MCNP but I have only done a brief look at all that modeling stuff 01-Jul-20 12:02 PM @nmz787You can run OpenMC anywhere lol, I have it running on my Windows laptop (WSL2), and on a 6 year old laptop running ubuntu 20.04, and running it remotely on a threadripper workstation via a ssh connection, and I will be running it on a big computing cluster soon 01-Jul-20 12:02 PM MCNP, not so much 01-Jul-20 01:12 PM Should try antiX, wayyy faster than Ubuntu 01-Jul-20 01:26 PM I only use the laptops for test cases that finishes in less than half an hour, then I throw together a script to run a bunch of detailed cases on the server 01-Jul-20 01:26 PM Or the workstation running Arch linux 01-Jul-20 05:59 PM I'm pretty much done with Ubuntu even for non laptops 01-Jul-20 05:59 PM It's pretty amazing how much more performance antiX is comparatively, and it worked out of the box for all my hardware... Had minimal setup to do, mostly just "start menu" shortcuts 01-Jul-20 05:59 PM Vs debian which just had enough setup needed that I got bored (I'm well past the phase of my life when doing sys admin stuff is tolerable for more than a few hours a year) 07-Jul-20 03:18 AM https://twitter.com/GigaBecquerel/status/1280445635406303233 07-Jul-20 03:18 AM damn it I want to use my hpge again 07-Jul-20 03:18 AM but LN2 is expensive 07-Jul-20 03:31 AM LN2 is expensive? In the Czech Republic, its ~ 0.1 eur/litre bulk price and ~ 0.3 eur/litre if you have to persuade them to sell you really small amount... I am quite surprised its more expensive in Germany... 07-Jul-20 03:33 AM I pay about 2€ per liter, incl. delivery 07-Jul-20 03:33 AM for small amounts, that is 07-Jul-20 03:33 AM ~40 l 07-Jul-20 07:33 AM If you don’t have access to bulk and only have a dewar filled when you need it you are looking at quite a bit. Last time I had my 7 liter dewar filled it was like $30 US cause it took like an extra several liters to get it down to temp as they have to flush it to bring it down to temp. Also in California we pay some of the highest electrical prices anywhere attached to a mainland. It’s not prohibitive but it’s enough that I try to stretch it out as long as it can go when i get it! Usually the worry of LOX concentration get me first though and I dump it. 07-Jul-20 09:27 AM Here if you show up Monday-Friday 9-5 it’s unattended 07-Jul-20 01:20 PM I’ve been trying to convince my sister or one of her friends who work at a liquid nitrogen ice cream parlor to help get me a couple liters 08-Jul-20 11:40 AM do positron sources (Na22) have any weird additional safety considerations that wouldn't be addressed by treating it like a strong beta+gamma emitter? 08-Jul-20 11:44 AM nope 08-Jul-20 11:44 AM they can't induce transmutations or activation, so I don't see additional reason for concern 08-Jul-20 11:48 AM I’d agree, nothing comes to mind 08-Jul-20 11:51 AM I did decon on some medical stuff containing Ge/Ge-68, there was nothing special to watch out for 08-Jul-20 11:51 AM at least nothing that I was informed about 08-Jul-20 11:55 AM Yeah we weren’t told anything special either during radiation safety training 08-Jul-20 11:55 AM Ive handled some stuff with 64Cu before 08-Jul-20 12:39 PM also neat, you can measure the pair production annihilation line with just Co60 https://aapt.scitation.org/doi/10.1119/1.2174030 08-Jul-20 12:40 PM oh it's very obvious with everything aboce 1 MeV in lead shielding 08-Jul-20 12:40 PM Yeah, you can, makes NAA a royal pain sometimes 08-Jul-20 12:40 PM So much for measuring anything that decays by pair production 08-Jul-20 12:41 PM in the empty spectrum of my lead castle the 511 keV peak is actually the most dominant peak, even higher than 609 and 1460 keV! 08-Jul-20 12:41 PM @qualia how thick is your lead shielding? 08-Jul-20 12:41 PM oh and if you like to experiment a bit take your neutron counter in a moderator and measure background rate with and without lead around it 08-Jul-20 12:47 PM the lead is 45mm thick, with 10mm mystery steel on the outside and a 2mm lining of what i believe is aluminum on the inside 08-Jul-20 12:47 PM interesting idea.. i haven't done anything with my neutron tubes in a long while 08-Jul-20 12:49 PM so it's about as thick as my castle, you should be able to see the 511 keV nicely 08-Jul-20 12:49 PM my Na(I) backgrounds are all lead x-rays 08-Jul-20 12:49 PM yeah they'll be terribly dominant in all your spectra 08-Jul-20 12:49 PM but beyond that 08-Jul-20 12:49 PM if you measure for a day or two 08-Jul-20 12:49 PM and look at a log plot of the spectrum 08-Jul-20 12:59 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200708_125300-7C809.jpg 08-Jul-20 12:59 PM probably need a longer count time for it to stand out.. i had a 3 day bg spectrum but then i realized my gain was set way too high 08-Jul-20 01:04 PM heh, whoops 08-Jul-20 01:04 PM oh, maybe it also makes a difference that my lab is in the basement 08-Jul-20 01:07 PM my sunroom labspace just has a thin sometimes slightly leaky wood/metal?/tile roof over it 08-Jul-20 01:07 PM california jiggles too much for basements 08-Jul-20 01:08 PM right 08-Jul-20 01:08 PM needs more lead! 08-Jul-20 01:16 PM http://blog.nuclearsecrecy.com/2014/06/06/feynman-and-the-bomb/ Fun read 08-Jul-20 01:16 PM Radiation Safety Man appears! 08-Jul-20 01:16 PM For the bonus safety considerations beyond "more lead than you'd expect", what is the activity and physical/chemical form of your Na-22? 08-Jul-20 01:19 PM a sealed 1-10 μCi check source from Spectrum Techniques 08-Jul-20 01:19 PM more lead than you'd expect 08-Jul-20 01:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A5774.png 08-Jul-20 01:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-748FE.png 08-Jul-20 01:20 PM The gamma from Na-22 sources in excess of a mCi have this very annoying habit of sneaking out of shielding. If you left a crack, it's gonna start showing up in other spectra you take. 08-Jul-20 01:20 PM [waves hand] Eh, that's fine and easy to contain in a lead pig. 08-Jul-20 01:21 PM i figured as much :D 08-Jul-20 01:22 PM also remember that Na22 also has a >1 MeV gamma, not just the e⁺ 08-Jul-20 01:23 PM That's "more lead than you'd expect" part. 08-Jul-20 01:23 PM @GigaSquirrel 1940s princeton seems insane 08-Jul-20 01:23 PM which has a half value layer of over 10 mm in lead 08-Jul-20 01:23 PM @GigaSquirrel 1940s princeton seems insane @idmb 1940s to 1960s seem insane 08-Jul-20 01:23 PM esp. the nuclear research from that time 08-Jul-20 01:24 PM We tend not to put Na-22 sources of any appreciable size anywhere near the counting facilities. 08-Jul-20 01:24 PM go read "you must be joking mr feynman" 08-Jul-20 01:24 PM I had so many great laughs from that 08-Jul-20 01:24 PM that was a real good read 08-Jul-20 01:24 PM feynman's a huge jerk and it's kind of endearing from a safe distance 08-Jul-20 01:25 PM As my bio on twitter used to say "Radiation janitor cleaning up 50 years of Science Gone Wild - less naked ladies, more exploding radioactive experiments" 08-Jul-20 01:25 PM nice 08-Jul-20 01:25 PM I do not miss doing decon & demolition work at the National Labs. 08-Jul-20 01:26 PM feynman's a huge jerk and it's kind of endearing from a safe distance @qualia I agree, but he seems like the kind of jerk I tend get along really well. Too bad it's a bit too late to find out 08-Jul-20 01:29 PM But back to Na-22, one of the tricks people will do when they don't have enough rooms to keep their sources far from the counting area is that they'll put a floor safe (or a concrete meter box) in the floor for source storage. Except if that Na-22 source is beefy enough and you didn't put large quantities of lead on ALL sides of the safe, you'll start to get gamma groundshine coming back up into the room. Na-22 is annoying for rad control but awesome for all kinds of experiments. 08-Jul-20 01:30 PM oh fun 08-Jul-20 01:33 PM Many tricks of "Why on Earth would they have done this?" were learned during the Science Gone Wild clean ups. Some of them were good ideas. 08-Jul-20 01:33 PM 'concrete meter box' is honestly a really cute idea 08-Jul-20 01:34 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-B281C.jpg 08-Jul-20 01:34 PM Like that? 08-Jul-20 01:34 PM (Hole in background) 08-Jul-20 01:34 PM I think that’s just a section of pipe in the concrete 08-Jul-20 01:35 PM spicy treestump 08-Jul-20 01:37 PM The firefighting manikin in the cabinet just out of view is weirder but I’m off topic at this point 08-Jul-20 01:37 PM Pretty much! 08-Jul-20 01:37 PM The cheaper version I've seen is one of these lined with lead. 08-Jul-20 01:37 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/2Q-C7C9F.png 08-Jul-20 01:37 PM Including the same utility worker lifting hook for the lid and sources within. 08-Jul-20 01:38 PM Makes sense 08-Jul-20 03:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200709_001140-F8A5A.jpg 08-Jul-20 03:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200709_002601-75AF1.jpg 08-Jul-20 03:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200709_002627-21BF3.jpg 08-Jul-20 03:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200709_003944-52FBA.jpg 08-Jul-20 03:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200709_004020-84263.jpg 08-Jul-20 03:43 PM huge dead ccd with CsI:Tl on it 08-Jul-20 03:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200709_002128-CC0D3.jpg 08-Jul-20 03:43 PM not often that you can see pixels with your own eyes 08-Jul-20 04:59 PM rrreminds me i have a couple of dead gendex x-ray sensors i've wanted to go scrape all the magic poison off of 08-Jul-20 05:07 PM I still need to get a working sensor 08-Jul-20 07:40 PM @qualia Did you get the $50 GXS-700 from eBay? 08-Jul-20 08:11 PM nop, someone tossed a couple into my hands that'd already had most of their CCD bond wires gnarled off 09-Jul-20 02:47 AM rrreminds me i have a couple of dead gendex x-ray sensors i've wanted to go scrape all the magic poison off of @qualia although CsI:tl is generally considered "non hygroscopic" I could still see it get wet in real time 09-Jul-20 02:57 AM oh neat :o 09-Jul-20 03:02 AM kinda 09-Jul-20 03:02 AM but still, a wet crystal is a wet crystal 09-Jul-20 03:02 AM if you want CsI:Tl I'd buy it nre instead of scraping it off of sth 09-Jul-20 03:02 AM https://www.ost-photonics.com/product-category/scintillation-crystal-2/csitl-scintillation-crystal/ 09-Jul-20 03:02 AM it really is cheaper than I expected 09-Jul-20 01:00 PM https://www.youtube.com/watch?v=n2f7kEeSXYg This is scary 09-Jul-20 01:00 PM those vats of acid, the dust clouds.. 09-Jul-20 01:00 PM I mean sure, the "pure" uranium isn't that active, but the Ra in those minerals 09-Jul-20 01:12 PM uh oh 09-Jul-20 02:52 PM Processing facilities and fuel fabs are exciting places. 09-Jul-20 02:54 PM oh I can imagine 09-Jul-20 02:55 PM Some are much cleaner than others. 09-Jul-20 02:55 PM this sounds like it's followed by a "but none are clean" 09-Jul-20 03:30 PM Those initial ore processing stages and ceramic making steps are messy, but not particularly worse than a plating shop. Keeping up on the cleaning is essential and generally they do. The rod and fuel bundle fabs are usually as spotless as a satellite assembly room. Don't want any extraneous bits going into a reactor and then getting activated. 09-Jul-20 04:45 PM I know individual fuel rods are not particularly dangerous and individual pellets are pretty safe but when he said they heat them causing the uranium to increase in density a subconscious alarm went off in my head if Not don’t make it more dense! That’s when it goes bang! 11-Jul-20 01:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_100014-057BA.jpg 11-Jul-20 01:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_100236-C975E.jpg 11-Jul-20 01:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_100304-23304.jpg 11-Jul-20 01:27 AM spicy polystyrene! 11-Jul-20 01:27 AM sadly I have no idea what the active compound is 11-Jul-20 04:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_103807-C6791.jpg 11-Jul-20 04:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_103843-83003.jpg 11-Jul-20 04:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_130739-CCFB2.jpg 11-Jul-20 04:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_131511-B4E11.jpg 11-Jul-20 04:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_132212-3D13C.jpg 11-Jul-20 04:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_132442-395DF.jpg 11-Jul-20 04:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_134356-35CF2.jpg 11-Jul-20 04:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200711_133922-D8353.jpg 11-Jul-20 04:59 AM behaves a lot like bc412 11-Jul-20 01:18 PM https://www.ebay.com/itm/312997884297 Any bets on what I just bought? Semiconductor or proportional detector 11-Jul-20 01:18 PM imo a good chance for semiconductor 11-Jul-20 01:30 PM i see 10MΩ and 33MΩ.. could go either way 11-Jul-20 01:30 PM at that price i kinda want one to play with, but shipping a box of fission fragments across the pond.. eehh 11-Jul-20 01:31 PM you think it's contaminated? 11-Jul-20 01:31 PM I'm not sure, the price screams proportional, but the pcb looks like only low voltage stuff 11-Jul-20 01:35 PM idk about proportional detectors, but everything I've read about surface barrier detectors is that they get gummed up with fission fragments ion implanting themselves in the detectors themselves with basically any use 11-Jul-20 01:35 PM to the extent that canberra doesn't even test them at the factory with actual sources (per a pic in one of the listings you linked to in #swap-meet, and also from other research on PIPSes) 11-Jul-20 01:35 PM it's almost certainly negligible from all but a background count rate perspective 11-Jul-20 01:38 PM ah 11-Jul-20 01:38 PM maybe you're thinking about recoil nuclei? 11-Jul-20 01:38 PM oh, maybe? 11-Jul-20 01:38 PM because it's not that common to measure fissile stuff with them ^^ 11-Jul-20 01:38 PM but the recoil nuclei are really low energy, my spectrometer has a 3V potential on the sample to prevent them from hitting the detector 11-Jul-20 01:57 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_2020-07-11-13-56-55-0437E.png 11-Jul-20 01:57 PM e.g. 11-Jul-20 01:59 PM hmm yep 11-Jul-20 03:12 PM https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=13696723 11-Jul-20 03:12 PM silicon junction detector 11-Jul-20 03:13 PM nice :D 11-Jul-20 03:13 PM 50 mm! 11-Jul-20 03:13 PM if it actually still contains the detector I might see myself forced to by one or two or 5 more 11-Jul-20 03:16 PM heh 11-Jul-20 03:26 PM so i've been on a cold antimatter kick lately, and i went looking for where antiprotons come from. i found this fun paper modeling CERN's Ir(p,p̅) target https://arxiv.org/abs/1601.04005 11-Jul-20 03:26 PM tl;dr 2000°C temperature rise in 400 ns funtimes 11-Jul-20 03:27 PM Oh damn 11-Jul-20 03:28 PM but it got me wondering what that must sound like, and it's surprisingly hard to find instances of someone sticking a pocket recorder in their spallation vaults 11-Jul-20 03:28 PM i did find this old set of recordings of 450 GeV protons being kicked into a beamdump and/or slammed into some carbon collimator blades http://lhc-collimation-project.web.cern.ch/sounds_and_movies.php 11-Jul-20 03:32 PM I wonder how little piezo contact microphones would do in those circumstances 11-Jul-20 03:32 PM And wow, that’s a sound I never expected to hear 12-Jul-20 08:49 AM went to the nearest forest and collected some mushrooms 12-Jul-20 08:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-C8CA7.png 12-Jul-20 08:49 AM let's dry & ash them and then take a spectrum! 12-Jul-20 08:49 AM apparently my area often goes to ~1 kBq/kg 12-Jul-20 08:49 AM wish I had gotten more, but there were just too many mosquitos 12-Jul-20 08:49 AM (1 kBq Cs-137, that is) 12-Jul-20 08:52 AM Ooh, fun. I remember Bionerd discussing radioactive wild boar in Germany due to them eating mushrooms that bioaccumulate Cs-137 from Chernobyl. ️ 12-Jul-20 08:54 AM yep, a family friend is a hunter and told me that the boars here (south-eastern germany) ften go above the legal limit of 600 bq/kg 12-Jul-20 09:10 AM some fungi are better than others at bio-accumulation 12-Jul-20 09:10 AM will be interesting to see the results 12-Jul-20 09:10 AM those look like mostly russula at a glance 12-Jul-20 09:10 AM small ones with narrow stems might be panaeolus and not sure what the one that is gill side up is 12-Jul-20 09:14 AM if this is what I think it is (Russula paludosa ) it should be one of the best accumulating ones 12-Jul-20 09:14 AM but honestly, my detection limit should be 0.5 Bq of Cesium-137, so I should be able to see anything 12-Jul-20 09:16 AM If I had a HPGe I would be constantly bugging my friend who lives in Oak Ridge to do the same sort of collecting 12-Jul-20 09:17 AM I should really sample some of the ones in Oregon 12-Jul-20 09:17 AM He is really into mycology (taxonomy paper in print and all) so he is always out finding stuff 12-Jul-20 09:17 AM ohh I'd kill for some samples from there 12-Jul-20 09:17 AM guess locally they have to take all their deer in to get checked out too...and sometimes people get their deer confiscated haha 12-Jul-20 09:31 AM (also the small cluster of caps/stems are Marasmiellus confluens according to my friend) 12-Jul-20 10:27 AM Neat thing Miniature X-Ray Generator with Pyroelectric Crystal 12-Jul-20 10:27 AM https://www.amptek.com/-/media/ametekamptek/documents/products/coolx.pdf 12-Jul-20 10:51 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F3052.png 12-Jul-20 10:54 AM Well that’s being forwarded to the reactor slack meme channel 12-Jul-20 04:14 PM @Addison-110m oh you're in Oregon? 12-Jul-20 04:15 PM Normally 12-Jul-20 04:16 PM Ah, me too 12-Jul-20 04:17 PM I go to Reed, about to start my senior year 12-Jul-20 04:19 PM Nice, I toured the reactor there years ago with my general chemistry class from Portland community college 12-Jul-20 04:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1594596020999579011168578827349-C8745.jpg 12-Jul-20 04:21 PM Oh cool! I’ve given a bunch of tours, though I think my favorite was for a couple of navy reactor operators who’d just left the service 12-Jul-20 05:32 PM I’d love to get a tour at some point. Seeing the pretty blue light is totally on my bucket list. 12-Jul-20 07:03 PM Anyone have any experience with EPICS ( + the ND 556 AIM module)? I know Carl Willis has his module working with it already, but also curious about good general EPICS resources/tutorials/examples anyone might be aware of 12-Jul-20 07:03 PM @rdpierce don't you? 12-Jul-20 07:04 PM Yes I do. 12-Jul-20 07:07 PM Good to know! I got about as far as getting all the modules compiled and I'm sort of blindly feeling my way around actually connecting to my ADC and getting data out. Did you have to write a whole new 'app' to do so, or is it possible to do just from e.g. the softIoc CLI? 12-Jul-20 07:10 PM There are a few options. 12-Jul-20 07:10 PM EPICS is a whole framework. 12-Jul-20 07:10 PM kitten@snoof  ~/EPICS/support/mca-7-8   master ●  ↵ SIGINT(2)  mcaApp/CanberraSrc/O.linux-x86_64/mcaAIM epics> dbLoadDatabase("dbd/mcaCanberra.dbd",0,0) epics> mcaCanberra_registerRecordDeviceDriver(pdbbase) epics> mcaAIMShowModules Module Type HW rev. FW rev. Owner name Owner ID Status Memory size Free address [1] 18543 segmentation fault mcaApp/CanberraSrc/O.linux-x86_64/mcaAIM progress 12-Jul-20 07:10 PM You run a softIoc that includes mcaAIM. 12-Jul-20 07:10 PM I'd really like to learn my way around the whole framework to see if I could use it for other hardware/experiments 12-Jul-20 07:11 PM That need to be on the same Ethernet segment as the AIM. The AIM does not speak TCP so it is non-routable. 12-Jul-20 07:12 PM Yep, I can see it in Wireshark, so I know communication works there 12-Jul-20 07:12 PM It puts the Ethernet interface in promiscuous mode with libpcap so probably needs root permission. 12-Jul-20 07:12 PM oh interesting 12-Jul-20 07:13 PM If you get that working, you can use any EPICS MCA client to control it and view the data. 12-Jul-20 07:13 PM Mark Rivers with UChicago / CARS at APS/Argonne wrote it. He has an IDL package that does some analysis. 12-Jul-20 07:13 PM However, it outputs data to a self describing file that can probably be converted. 12-Jul-20 07:13 PM I also know Carl Willis wrote something in LabView. 12-Jul-20 07:13 PM But EPICS is its own framework. You can write your own code and link it to EPICS. C++ is popular, as is Python. A lot of EPICS work happens with Python. 12-Jul-20 07:13 PM Basically, you just need to leave the softIoc running somewhere. It will take ownership of the AIM. Then anything that speaks EPICS running anywhere on your network can discover the channels corresponding to the AIM, can control the AIM to start and stop collecting data, set parameters, and, if you’re using a Canberra ADC, amp, and/or HV bias supply that uses ICB, EPICS can control these modules via the AIM. 12-Jul-20 07:13 PM EPICS is like a big LEGO set. Once you’ve got the AIM linked in, you can connect it to any of your other toys. 12-Jul-20 07:13 PM This is why I love EPICS. I’ve built a computer controlled beer brewing system using it. 12-Jul-20 07:13 PM It also can bridge to GPIB, Modbus, and talk to all sorts of hardware. 12-Jul-20 07:21 PM that's amazing 12-Jul-20 07:21 PM yeah, this seems like definitionally the Right Thing for me to use as control plane hardware for all of my physics systems (plus it seems like experience with it immediately becomes useful a lot of interesting places) 12-Jul-20 07:21 PM for the MCA viewer, did you mean this? https://cars.uchicago.edu/software/idl/mcaDisplay.html 12-Jul-20 07:23 PM And the “asyn” module lets you script communications with various hardware that uses serial, a TCP port, etc. to link process variables in EPICS to the hardware. 12-Jul-20 07:23 PM Yes, that’s it. 12-Jul-20 07:23 PM It’s optimized for x-rays. Has a library of x-ray energies. 12-Jul-20 07:23 PM Which is great if you’re doing XRF, not so useful for analyzing fission products with an HPGe or NaI. 12-Jul-20 07:23 PM Hey, didn’t a national lab release an analysis package for spectroscopy? 12-Jul-20 07:25 PM ah yeah, InterSpec! 12-Jul-20 07:25 PM I think 12-Jul-20 07:26 PM Also, I have my alpha spectrometer working with EPICS and IDL, so while I can display alpha spectra, there clearly isn’t a library for alpha energies. 12-Jul-20 07:26 PM The IDL app can do background subtraction, various peak fitting. 12-Jul-20 07:26 PM Wow, those docs on the IDL app are dated. 12-Jul-20 07:26 PM I can ask Mark Rivers if he has later documentation. 12-Jul-20 07:26 PM Although you don’t need this. 12-Jul-20 07:26 PM Actually, hmmm.... I know you can control everything using MEDM which is an archaic, janky Motif interface. 12-Jul-20 07:26 PM I don’t know if you can save data files. 12-Jul-20 07:26 PM I’d suggest doing your analysis in a tool like InterSpec. You don’t need a lot of bells and whistles just to control the spectrometer. 12-Jul-20 07:26 PM That would mean you don’t need to install something heavy weight like IDL or LabView. 12-Jul-20 07:30 PM for sure, i was strongly considering just writing a bit of python to turn the thing on, snarf some data and dump it to a file 12-Jul-20 07:37 PM That makes a lot of sense. 12-Jul-20 07:37 PM I mean, it helps having a GUI to visualize while capturing. But then yeah, doing data analysis via another mechanism. 12-Jul-20 07:37 PM I think the Canberra AIM and ADC is probably the best kept secret. Everyone thinks it only works with an unobtainium Genie2k license. 12-Jul-20 07:37 PM So these modules can typically be found for <$100 on eBay. 12-Jul-20 07:40 PM yeah, i'm actually really excited to get this working and get both ADCs hooked up to it 12-Jul-20 07:40 PM I also have a thing that uses IDL (but didn't come with the right cable for it) and I'm actually not certain what it's used for, but i think it's a mixer frontend 12-Jul-20 07:41 PM And for this you get an 8k channel MCA with a 100 MHz Wilkinson ADC. 12-Jul-20 07:41 PM it's a Canberra 8224 AMX 12-Jul-20 07:41 PM They have stabilizers and DSPs. 12-Jul-20 07:41 PM Ok that’s primarily for alpha counting so you can have a lot of chambers and detectors sharing one ADC. 12-Jul-20 07:41 PM https://cars9.uchicago.edu/software/epics/mcaCanberra.html 12-Jul-20 07:41 PM These are the modules that are supported. 12-Jul-20 07:41 PM 0 = ADC (9635) 1 = Amplifier (9615) 2 = High voltage power supply (HVPS) (9641, 9645) 3 = Three-channel analyzer (TCA) (2016) 4 = Digital signal processor (DSP) (9660) 12-Jul-20 07:41 PM I have a non-ICB ADC, and both a non-ICB and an ICB 9615 amp. 12-Jul-20 07:47 PM Know any secret tricks for finding/making more MCA/ICB cables? 12-Jul-20 07:47 PM I'd go rummaging for IDE cables and hacksaw to size, but there's a small plastic box + breakout between the one cable I have that goes from my ADC to AIM 12-Jul-20 08:05 PM I believe they are standard 2x? IDC cables. 12-Jul-20 08:05 PM If so, they’re trivial to fabricate. Buy the connectors. Buy ribbon cable. Thread through the ribbon cable, stick in a vise, and squeeze. Just make sure the polarity is correct, such that you don’t crimp a connector on backwards. 12-Jul-20 08:05 PM I believe IDC works in a bus architecture, so you can crimp several connectors on one cable. 12-Jul-20 08:08 PM ah, convenient 12-Jul-20 08:10 PM Make sure your module spacing in the crate works before crimping. There’s nothing worse than finding out that a BNC jack you didn’t think about got in the way and the cable is 1/4” too short. 13-Jul-20 10:07 AM https://twitter.com/atomicarchive/status/1282716065756258305 13-Jul-20 10:59 AM very interesting 'hold it there for a while and count to ten' technique 13-Jul-20 11:05 AM it cures vision 13-Jul-20 11:05 AM can't really read what it says on there, about activity and or dose 13-Jul-20 11:05 AM 130 rep(?)/min 13-Jul-20 11:05 AM oh, til 13-Jul-20 11:05 AM https://en.m.wikipedia.org/wiki/R%C3%B6ntgen_equivalent_physical 13-Jul-20 11:05 AM The rep has variously been defined as 83 or 93 ergs per gram of tissue (8.3/9.3 mGy)[2] or per cm3 of tissue.[3] 13-Jul-20 11:05 AM wow 13-Jul-20 11:18 AM oh, so 'count to ten' might've been a bit high 14-Jul-20 02:39 AM http://freshlab.org/detektor/?lang=eng 14-Jul-20 02:39 AM that spectrum is pretty impressive 14-Jul-20 02:39 AM he's talking about 1.5 keV fwhm @ keV 14-Jul-20 02:39 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/am-ADF1B.png 14-Jul-20 07:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200712_170043-22E04.jpg 14-Jul-20 07:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200714_161359-CB944.jpg 14-Jul-20 07:45 AM muh' shrooms 14-Jul-20 07:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200714_163625-813DF.jpg 14-Jul-20 07:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200714_164101-63B6F.jpg 14-Jul-20 07:45 AM I can tell right away that the activity is not very high 14-Jul-20 09:19 AM think most of the papers ive seen talk about concentrations in the low parts per billion so that isnt terribly surprising 14-Jul-20 09:19 AM i would be surprised if anything besides your HPGe really give any kind of results...but crossing my fingers 14-Jul-20 09:34 AM from what I found it may be ~300 Bq per kg 14-Jul-20 09:54 AM that sounds rather high unless they were working with mushrooms from an area with high levels of radiation to begin with? 14-Jul-20 10:10 AM I'm living in an area that got a bit more chernobyl fallout 14-Jul-20 10:10 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/efb2b21b116aa6ff7e9ce74195afc628-3AC38.jpg 14-Jul-20 10:10 AM that red spot in the middle of europe 14-Jul-20 10:10 AM the boars here often go above 600 Bq/kg 14-Jul-20 10:10 AM just Cs137, that is 14-Jul-20 10:45 AM ahhh that would explain it pretty well then, and the cs137 would probably be a bit easier to pick out than your average background U/Th 14-Jul-20 01:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/tumblr_7fff7c6c91654ab859d59b8f35bf712a_24-6DCDC.jpg 14-Jul-20 02:12 PM hm 14-Jul-20 02:13 PM has someone posted the "this is not a place of honor" shorts here yet 14-Jul-20 02:13 PM i got in contact with someone from scionix who's apparently really good at getting a high Resolution from NaI crystals 14-Jul-20 02:13 PM oh interesting 14-Jul-20 02:13 PM has someone posted the "this is not a place of honor" shorts here yet @Addison-110m I am pretty sure they were here before but they're always welcom :D 14-Jul-20 02:13 PM He got his NaI to 6% fwhm! 14-Jul-20 02:13 PM and now I'm trying to get his secrets 14-Jul-20 02:13 PM high blue sensitivity pmt of course, but also a Treatment of the crystal itself 14-Jul-20 02:13 PM and really the only thing that comes to mind is heat, because I don't think that anything chemical will diffuse deep enough, light is known to be bad for it 14-Jul-20 02:13 PM now I'm wondering if it's actually just heat or what 14-Jul-20 02:13 PM i know yellow crystals can be made better with heat, but I never got below 10% with that 14-Jul-20 02:18 PM maybe it is not just heat but a specific kind of heating and cooling to anneal the defects out of the crystals 14-Jul-20 02:18 PM I should try it with a known good crystal to see if it actually changes anything 14-Jul-20 02:18 PM yeah that's also a good point 14-Jul-20 02:18 PM he's hinted at a treatment for resolution and conditioning for long term stability a few times in a forum, calling it a company secret 15-Jul-20 02:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/01b04ef4a07816cb-2A2D8.png 15-Jul-20 02:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-97CA3.png 15-Jul-20 02:45 AM not much of a peak in the red area 15-Jul-20 02:45 AM maybe a bit? 15-Jul-20 02:45 AM but 15-Jul-20 02:45 AM meh 15-Jul-20 02:45 AM not the activity I was hoping for 15-Jul-20 07:03 AM Oh cool you can bypass the profanity filter with images 15-Jul-20 03:41 PM I mean you can probably just put a zero width space in too 16-Jul-20 07:59 PM argh, i'm so close to getting this working.. 16-Jul-20 07:59 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1594954724_20200716-190744-5FAF2.png 16-Jul-20 07:59 PM dunno why medm isn't giving me a spectrum output, and for some reason the ADC keeps slamming to 100% deadtime and sticking there until i go and flip the coinc/anticoinc & pha/sva toggles 16-Jul-20 07:59 PM caget mcaTest:aim1_adc1Read is also not working properly, so maybe that needs to be working first 16-Jul-20 08:18 PM ooh, i got the cartesian graph working.. need to build medm with sciplot 16-Jul-20 09:50 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1594961376_20200716-210736-60CF6.png 16-Jul-20 10:12 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1594962634_20200716-220734-7CBAC.png 16-Jul-20 10:12 PM apparently there's already an actively maintained puppet module for deploying epics 16-Jul-20 10:12 PM i'm so excited 17-Jul-20 12:02 AM Ohh, it works? 17-Jul-20 12:02 AM congrats! 17-Jul-20 08:05 AM I'm laughing way too hard at this 17-Jul-20 08:05 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B4358.png 17-Jul-20 09:00 AM Congrats @qualia 17-Jul-20 09:00 AM Here’s what’s up: the ADC sees a pulse, converts it, then waits for the AIM to acknowledge having read it. 17-Jul-20 09:00 AM It is effectively dead in this time. 17-Jul-20 09:00 AM If the AIM doesn’t get back fast to the ADC, the ADC just sits there stupidly latching that value. 17-Jul-20 09:00 AM And it displays 100% dead time because it is dead. 17-Jul-20 09:00 AM This is actually a problem for alpha spectroscopy. 17-Jul-20 09:00 AM Keep in mind backgrounds there are measured in terms of counts per day. 17-Jul-20 09:00 AM So if I stop acquiring, and there’s still a sample in the chamber, I believe the ADC will latch the next pulse. Then if I vent the chamber, pop out the sample, and either put in a new one, or run the detector to check the background and make sure the sample didn’t contaminate the chamber, there’s going to be something latched that shows up when I acquire a spectrum. 17-Jul-20 09:00 AM This is negligible for typical gamma spec with reasonably hot sources, but it isn’t for something at a low count rate like alpha spec. 17-Jul-20 03:08 PM Ohhh, huh! Okay. Yeah, like, I have two tiny 176Lu crystals I'm measuring right now on a tiny NaI, so it's not super lively; the deadtime counter on the UI slams back and forth between 0% and 90% and the LED bar graph flits up to 100% when I stop acquisition. That makes sense 17-Jul-20 03:08 PM Now I get to play the gain staging game a whole bunch, hooray 18-Jul-20 03:59 AM https://www.fusionforum.net/forum/viewtopic.php?f=84&t=214 18-Jul-20 06:45 AM wow, even watercooled 18-Jul-20 06:45 AM safely mechanically controlling circuits over enormous potential gradients with careful use of lucite extend-o-rods will never cease to be the most novel thing to me 18-Jul-20 06:48 AM isn't there a pic of a scope with its frontpanel mechanically offset for isolation, with dozends of lucite sticks? 18-Jul-20 06:50 AM oh yes 18-Jul-20 06:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200718_065019-95074.jpg 18-Jul-20 06:50 AM YES 18-Jul-20 06:50 AM i despise this vile instrument and all that it stands for 18-Jul-20 06:51 AM also how do you turn power on and off 18-Jul-20 06:52 AM presumably through the floated isolation transformer it's being cursed by 18-Jul-20 06:54 AM I should really build one of those isolation thingies, motor and generator and like half a meter of lucite 18-Jul-20 06:54 AM hmm I still have that x-ray transformer that does 2x45 kV against the (grounded) core, I could float it to make 90 kV against ground 18-Jul-20 08:23 AM We have a bunch of electrometers with sticks like that 18-Jul-20 12:24 PM Currrrrrrrrsed 18-Jul-20 01:46 PM I am reminded of how I control my musical Tesla coil via fiber. 18-Jul-20 01:46 PM Isolation - not just for COVID-19. 21-Jul-20 12:06 AM I'm seeing a growing community of people using Gendex Oralix AC x-ray heads. Does anyone here by chance have one? Are these a very popular head? Note I don't have one, just that I've had several people send me schematics for them (ex: the page nats made here: https://nucwiki.org/wiki/index.php/Gendex_Oralix_AC) 21-Jul-20 12:15 AM The cursive in that amateur proton accelerator is basically another language to me (which I can't read) :/ 21-Jul-20 03:33 PM I’m very much not happy to hear that there’s a growing community using them if they aren’t dentists, @digshadow. That particular head is plentiful because it is backward compatible with systems that are many decades old. As a reminder, take care to not become an Radiation Producing Machine Manufacturer by accident m. Know the rules & regs in your locality about possession and use of RPMs before you start messing with them. 21-Jul-20 03:58 PM Totally haven't had a heilodent md sitting in the trunk of my car for the past few months 21-Jul-20 04:36 PM Well I know it isn’t the one we’re trying to sell because Excess & Salvage isn’t picking anything up at the moment. 21-Jul-20 04:56 PM Do you have the remote for yours? 21-Jul-20 04:56 PM That's the one thing I'm missing, I've got it hot wired so I can relay trigger it, but it'd be nice to use the actual control interface 21-Jul-20 10:22 PM [wince] That's the kind of modification that makes regulators sad, especially if your machine ever leaves your possession in remotely operable condition. The kind of modification that makes you criminally liable. And ours is dead man switch operated, for step to the other side of the shielded partition and press button style of operation. 22-Jul-20 12:20 PM https://twitter.com/lougrims/status/1286017319911784451 22-Jul-20 12:20 PM Someone sent me a link to this today. I had never heard about it before. 22-Jul-20 12:20 PM Report is an interesting read 22-Jul-20 12:20 PM "After dinner, they consumed some alcohol (vodka). However, they felt unusually sick after only a small amount (about 100 mL) and could not sleep" 22-Jul-20 12:30 PM And apparently they still have a couple of those sources that have not been found. 22-Jul-20 01:03 PM This was discussed in this channel at some point before. The report contains very much NSFW pictures, just fyi for people who haven't read through it already 22-Jul-20 01:03 PM https://www.youtube.com/watch?v=5YBXJSgbtS0 22-Jul-20 01:03 PM Video showing the recovery process of the source 22-Jul-20 01:14 PM Yeah good warning. Seeing the pic it's amazing that they all survived 22-Jul-20 01:44 PM It’s the kind of thing that causes nightmares for people in my field, but it’s also what we’re around to wrangle when they pop up. While not this bad, the orphan source program has been doing a lot of response in Africa as of late thanks to what is effectively dumping. 22-Jul-20 01:54 PM Yeah did not tag you on twitter since I figures you probably knew about it already. It's just so surprising to me that sources like those could end up randomly popping up. 22-Jul-20 01:54 PM also interesting part of the report was about how they thought it was probably better to just leave it cordoned of until summer to make recovery easier but local political pressure has them pick it up in winter 22-Jul-20 03:14 PM Sometimes you can rely on remoteness or inaccessibility, like the bottom of a well or an isolated high Arctic island, to help limit access. But then you find out nowhere is as remote as you, urbane city dweller with rad meters and detailed plans, think. 22-Jul-20 06:33 PM I mean that's effectively what mine is, it's jumpered to enable the trigger, and then has a momentary trigger, on a rather long leash so you're not near it. I'm not crazy enough to have it do something stupid like emit whenever you plug it in to the wall, it's only rated for 3 second bursts maximum 22-Jul-20 07:26 PM I'm not crazy enough to have it do something stupid dangerous thought process! 22-Jul-20 09:32 PM The things I have seen people do to override safety controls on medical x-ray units... To paraphrase the comedian Doug Stanhope, "You swapped the dead man switch on the dental unit for a garage door opener and clicker, and that's why I drink." 23-Jul-20 11:33 AM it sucks that it's not easier to Do The Right Thing short of simply not doing the thing, re: hobbyist radiation work 23-Jul-20 11:33 AM i still maintain the NRC should spin off a hobbyist licensing/regulation association a la ARRL 23-Jul-20 11:33 AM keys up callsign on rod pinch diode 23-Jul-20 11:38 AM Strongly agreed 23-Jul-20 11:38 AM Speaking of which, you still interested in potentially getting a ham license? 23-Jul-20 11:39 AM I am 23-Jul-20 11:39 AM I'm still waffling on changing my legal name again since your whole name change history becomes public record once you do 23-Jul-20 11:39 AM but sssooomeday 23-Jul-20 11:39 AM i have mischief to get up to 23-Jul-20 11:40 AM Yeahhhhhhhhhhh, it sorta does 23-Jul-20 11:40 AM I’ve got more information on remote license exams that are more practical than the Alaska VEC that I think I sent you info on 23-Jul-20 11:41 AM oh yeah, that's a thing that's happening now 23-Jul-20 11:42 AM I’m trying to get another radioactive material handling certified person at reed to get a ham license to break the record for highest energy contact 23-Jul-20 11:42 AM uh oh 23-Jul-20 11:42 AM :D 23-Jul-20 11:42 AM @Addison-110m but yeah feel free to toss info in my DMs or w/e 23-Jul-20 11:46 AM Sure! 23-Jul-20 04:28 PM Honestly, you have a lot more freedom to tinker with RPMs than you do with radioactive materials, regardless of my personal opinions on relative hazards, because of the general regulatory structures around the globe. The victims of RPMs tend to be the operators themselves; for radioactive materials it tends to be innocent bystanders or site contamination issues and the responsible party is long gone/cannot even begin to pay for cleanup costs. That's why the structures are different. 23-Jul-20 04:29 PM Virginia has a wild section in it's laws that I wish was more common 23-Jul-20 04:29 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-2C6EC.png 23-Jul-20 04:30 PM https://tenor.com/view/welp-um-no-nathanfillion-gif-9890350 23-Jul-20 04:30 PM That's the usual HP reaction to that particular one. 23-Jul-20 04:31 PM somehow build a multi kilowatt xray laser, sure no problem whatsoever 23-Jul-20 05:20 PM omg, I am sorry but that's just hillariously dumb 23-Jul-20 05:20 PM I can't imagine that's not from the days of xray shoe fit viewers... 23-Jul-20 05:29 PM Lets keep it that way, I like having my xray unit 24-Jul-20 05:16 AM This was discussed in this channel at some point before. The report contains very much NSFW pictures, just fyi for people who haven't read through it already @Mason_Yu Depends on where you work! 24-Jul-20 05:16 AM I remember reading about that probably 10-12 years ago in my first or second college biology class 24-Jul-20 03:36 PM @Addison-110m Heh, At one of the Nordic VUSHF meetups there was a competition for "longest QSO in terms of wavelengths". The Swedes brought some 47GHz and 76GHz gear and ware boasting about that. Then a certain bearded fellow hooked up a CW key to a dental X-ray head and the swedes ware much more quiet. 24-Jul-20 03:36 PM This was 10-20years ago or something. 24-Jul-20 03:37 PM Oh amazing (and sorta terrifying) Current record stands at 1.3MeV I think 24-Jul-20 03:37 PM @qualia Btw some folks over at the SignalsEverywhere discord have VE and can do online testing under GLAARG 24-Jul-20 03:38 PM Yeah GLAARG is the VEC who I did my extra exam through 26-Jul-20 10:18 AM wowz 28-Jul-20 11:37 AM Where do folks get big custom lightpipes from? been wondering how many photomultipliers i could stick on this bicron cutting board https://www.ebay.com/itm/273816116212 28-Jul-20 11:37 AM maybe tap plastics could canoodle something together, but i've never used them for more than 'gimme your cheap scraps and/or one (1) Square of Plastic' 29-Jul-20 06:53 PM I have a request from one of my researchers that I think is probably good to bring here. Anyone know people doing Faxitron cabinet repair in the SF Bay Area? Their budget is grad student-grade limited. 30-Jul-20 11:17 AM I really want to know what was in there 30-Jul-20 11:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/P1030797-353A4.JPG 30-Jul-20 12:11 PM It is a mobile portal into the physical manifestation of the Q Continuum. What else would it be? 30-Jul-20 12:12 PM but look at the size of the thing! 30-Jul-20 12:12 PM I just want to know how much of that volume was crystal and what was padding 31-Jul-20 02:24 AM @funranium @digshadow @digshadow maybe? 31-Jul-20 09:53 AM @funranium what model 31-Jul-20 09:53 AM I just gave away a lot of my spay parts to @qualia though.... 31-Jul-20 09:53 AM Spare 01-Aug-20 01:23 AM happy to redirect any of 'em to anyone that could make better/more immediate use of them 01-Aug-20 01:23 AM dunno if you're, in particular, looking for a licensed cabinet x-ray repair tech tho 01-Aug-20 01:23 AM i am: not that 01-Aug-20 08:37 AM Does anyone have manuals for the Faxitron cabinets? 01-Aug-20 08:48 AM FWIW, my friend with the non-profit who has the Faxitron Micro50 got the chemistry, film, and film processing machine to work, and the radiographs are much better quality than the Raspberry Pi hacked camera system. 01-Aug-20 08:48 AM He also has a 100 kV cabinet that I haven’t seen yet. 01-Aug-20 08:48 AM We are very interested in applications of this for reverse engineering electronics. 01-Aug-20 11:01 AM Yeah, they’re looking for a repair tech. 02-Aug-20 03:21 AM ok 02-Aug-20 03:21 AM so 02-Aug-20 03:21 AM I got this 50 mm Si alpha detector 02-Aug-20 03:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D4199.png 02-Aug-20 03:21 AM and I'm thinking about coating it with Gd to make it neutron sensitive 02-Aug-20 03:21 AM yay or nay? 02-Aug-20 03:34 AM gut feeling is 'coat a thin foil first and mount it in front as a proof of concept' 02-Aug-20 03:34 AM how would you coat it? 02-Aug-20 03:41 AM hm good idea 02-Aug-20 03:41 AM evap 02-Aug-20 03:41 AM my coater is almost done ™️ 02-Aug-20 03:50 AM Wouldn't the heat damage it? 02-Aug-20 03:51 AM aren't wavers commonly PVDed? 02-Aug-20 03:51 AM I've been told that that's the way to coat detectors, but I didn't question it any further 02-Aug-20 04:08 AM I don't have any experience with evaporative coating, but I just know that heat can be sometimes an issue. If you think it will be OK, then why not 02-Aug-20 06:01 AM never had any issues with heating substrate, even on 30 min+ runs. You’re doing it in pretty good vacuum so all ur heat transfer is radiation 02-Aug-20 06:13 AM what's the heating power of the actual coating? 02-Aug-20 06:16 AM Is it necessary to coat metallic Gd? Gd2O3 powder can be brought into a slurry, e.g. using isopropyl alcohol. Afair there also were some common Gd compounds that were soluble in water 02-Aug-20 06:22 AM in theory yes, but I don't want the absorber layer to be too thick, or it would self absorb the resulting radiation 02-Aug-20 06:22 AM also I want to use my coater 02-Aug-20 07:14 AM https://www.reddit.com/r/chernobyl/comments/hm5be7/rbmk_1000_reactor_simulator_by_simgenics/?utm_source=share&utm_medium=ios_app&utm_name=iossmf 02-Aug-20 07:14 AM Just saw this last night. Very addictive time waster. 02-Aug-20 07:14 AM Demonstrating just how unstable RBMK’s are at low power. 02-Aug-20 07:14 AM Trying to restart after a drop in power, I’m withdrawing control rods and suddenly I’m not getting an increase in neutrons. Then I realize, uh oh, I’m really in a xenon well, I’ve pulled all the central control rods out to 100% and I still need to pull more rods, this isn’t good, where have I seen this before??? 02-Aug-20 07:14 AM Not to mention how obnoxious it is to deal with a turbine trip.... 02-Aug-20 09:58 AM I just told my gf to check the water level in the steam separator drum of the espresso machine. 04-Aug-20 10:17 AM oh man I got a big pack of high voltage today 04-Aug-20 10:17 AM 12 kV diodes 04-Aug-20 10:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CB35D.png 04-Aug-20 10:17 AM chinese 30 kV power supply 04-Aug-20 10:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-654E2.png 04-Aug-20 10:17 AM giant 2x 50 kV transformer 04-Aug-20 10:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7F068.png 04-Aug-20 10:36 AM hehe nice 04-Aug-20 06:24 PM ooh precipitator supplies 04-Aug-20 09:04 PM New stuff for me as well. Just acquired a pancake and an energy compensated end window tube to fix an ADM-300 frisker and base unit. 04-Aug-20 10:49 PM That should make some nice arcs! 04-Aug-20 10:50 PM From what I reay the power supplies really dislike arking and die within seconds :/ 04-Aug-20 10:50 PM https://www.fusionforum.net/forum/viewtopic.php?f=40&t=434 04-Aug-20 10:50 PM but the transformer... That should give some nice arcs at ~100 kV 04-Aug-20 10:50 PM gotta figure out the pinout diagram first 04-Aug-20 10:50 PM at least I'm fairly certain it doesn't contain PCBs 05-Aug-20 06:54 AM how do you know that it is not PCB oil, with a test? 05-Aug-20 06:54 AM taste XD 05-Aug-20 06:59 AM yep! 05-Aug-20 06:59 AM No, I opened it (outside) and burnt a drop of the oil 05-Aug-20 06:59 AM if there's a hit of green you should suspect PCBs 05-Aug-20 06:59 AM but there wasn't 05-Aug-20 06:59 AM also it just smells like hydrocarbon oil, PCBs are usually described as "fruity", but I never got to smell any 05-Aug-20 06:59 AM not that I was aware of anyways 05-Aug-20 06:59 AM https://www.youtube.com/watch?v=8ecDhs2V_fU 05-Aug-20 07:50 AM No, I opened it (outside) and burnt a drop of the oil @GigaSquirrel but allot of PCB oils dont have those colors when burning, if it is bevor 1990 it is most probably PCB exclusively used that for x ray transformers, there are allot of different kinds of PCB oil, learned that from a fried, they do oil replacement for transformers and Capacitors. Nice arc, the fun to have with something like that 05-Aug-20 07:51 AM I know there are a lot of PCBs, but all should have chlorine in them, causing the flame coloration... 05-Aug-20 07:51 AM but I would not mind doing another test, do you have any recommendations? 05-Aug-20 08:08 AM i had tried it once and did not see any difference in the flame. hmm i just let my fried test it at work, maybe i can ask if there is an easy DIY test or if he could test it for you. The only thing i know(but did not test it my self), these oils are often heavier than water 05-Aug-20 08:16 AM would be great if you asked him, thanks 05-Aug-20 08:16 AM now I'm wondering, wiki says PCBs were used as insulating oil, were they used as additive or as pure chemical? 05-Aug-20 08:16 AM because the oil in my xformer burns very well 05-Aug-20 08:16 AM and PCBs are supposed to be non burning 05-Aug-20 08:37 AM burns well with a bright yellow flame, floats on water and doesn't smell "fruity" 05-Aug-20 08:37 AM I think I'll still do a test, but I won't lose much sleep until then 05-Aug-20 08:37 AM oh I should be able to test at work 05-Aug-20 08:37 AM power plant built in the 60s, I bet we had some issues with PCBs 05-Aug-20 08:37 AM we still always test for asbestos every time some insulation is exposed 05-Aug-20 09:36 AM I went through remediation of a tube factory built in the early 60’s two years ago. Every oil transformer in the place was 100% PCB oil and none of it had the telltale smell. It was actually the really good pure shell stuff. There had been one leak. An x ray transformer. Fortunately we got on it right way and it did not penetrate the concrete slab. We got a complete clean report without too much trouble. I sent several tons of oil transformers and caps to emerald transformer recycling company who handled it and after the scrap value of the metals the total environmental remediation costs were about 20K for an 11,000 foot facility. For liberal ecomental California we got off really easily! 05-Aug-20 09:36 AM There were about 20 X ray transformers there, 10 pole pigs, 2 transmission grade 100 kVA units and hundreds of small like 1 to 4 KVA transformers. 05-Aug-20 09:36 AM All got ground up, metal separated, and oils burned out, or the non recycled ones probably dumped in a pit In Nevada. 05-Aug-20 10:35 AM well that sounds like fun 06-Aug-20 02:09 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B9F07.png 06-Aug-20 02:09 AM hyperventilates 06-Aug-20 02:09 AM ahhhhhh 06-Aug-20 04:14 AM holy buckets 06-Aug-20 04:14 AM 2.57% is ridiculous 06-Aug-20 04:15 AM yesss ❤️ 06-Aug-20 04:15 AM I asked about how they measured it, what pmt etc 06-Aug-20 04:15 AM afaik this can only be achieved with a SBA or UBA photocathode 06-Aug-20 08:43 AM Yassss..... that’s impressive. 07-Aug-20 03:08 AM The PMT we used was Hamamatsu R6231-100. 07-Aug-20 03:08 AM Yeah, that's SBA 07-Aug-20 03:08 AM so I guess I could do like 3% with bialkali 07-Aug-20 03:08 AM but I'm working on getting a SBA pmt 09-Aug-20 03:48 PM well that would have been a cool purchase... 09-Aug-20 03:48 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-9867B.png 09-Aug-20 03:57 PM 8 mCi Cs-137 + 40 mCi AmBe? Spicy.... 11-Aug-20 10:59 PM A friend of mine found a bottle of ⁶LiD and now we're wondering if that's regulated in any way 11-Aug-20 10:59 PM @funranium got any info on that? 12-Aug-20 02:18 AM ooh 12-Aug-20 02:31 AM aside from spooky hugoniots and thermal-to-14 MeV converters, apparently 6LiD has really interesting nuclear polarization properties 12-Aug-20 02:31 AM https://www.researchgate.net/publication/237636340_Polarization_Build_up_in_Compass_6LiD_Target 12-Aug-20 04:03 AM hugoniots? 12-Aug-20 05:57 AM also that paper is very interesting and I understand very little of it 12-Aug-20 07:09 AM That’s... enriched H-bomb fuel??? 12-Aug-20 07:09 AM Not that you can make it go boom without a critical mass of Pu.... 12-Aug-20 07:09 AM yeah basically 12-Aug-20 07:09 AM but I'm wondering if it's regulated on its own 12-Aug-20 07:09 AM looks like you can buy both ⁶Li and ²H without any issues 12-Aug-20 07:09 AM worst case would be some dual use license I think? 12-Aug-20 07:13 AM On the subject of H-bombs, I’ve got some interesting scorched plastic from a broken arrow incident. 12-Aug-20 07:13 AM I’m questioning if it is interstage material. 12-Aug-20 07:13 AM If so, I would love to test it. That was one of the big drivers for me getting the ICP-MS working. 12-Aug-20 07:13 AM If it was polyethylene or polystyrene and doped with something, that’d be cool to know. 12-Aug-20 07:13 AM This was a really old nuke, a Mk-17; I’ve heard the interstage is now an aerogel. 12-Aug-20 07:18 AM get your hands on an ftir, that would be ideal for that 12-Aug-20 07:18 AM How im the hell did you get that 12-Aug-20 07:19 AM It was sitting on the ground decades after the accident. 12-Aug-20 07:19 AM Idk us law but wouldnt the parts of a nuke be classified and guarded? 12-Aug-20 07:19 AM H bomb construction is still secret afaik 12-Aug-20 07:20 AM Scorched plastic. A Mk-17 accidentally came loose in a bomb bay near Albuquerque. Broke through the doors, hit the ground, the HE detonated. It didn’t have the Pu pit inserted. 12-Aug-20 07:20 AM Apparently made a big crater and took out a cow. 12-Aug-20 07:21 AM Oof 12-Aug-20 07:21 AM It’s also possible that this is melted plastic from the parachute in the tail, in which case it’s much less interesting. 12-Aug-20 07:21 AM FTIR? 12-Aug-20 07:21 AM I actually do have access to one. 12-Aug-20 07:21 AM Only problem is it only can do transmission, and I don’t have a microtome to section this. 12-Aug-20 07:23 AM ah, that sucks 12-Aug-20 07:23 AM the one at work only does reflection 12-Aug-20 07:24 AM I’ve heard it suggested that if it is interstage, it might be deuterated polyethylene. Which means the ICP-MS wouldn’t see it because its minimum Z is 3. 12-Aug-20 07:24 AM The military cleaned up after the accident, but this plastic could still be found decades later. 12-Aug-20 07:24 AM I’ve also heard the property is now completely developed, so it can no longer be found in the wild. 12-Aug-20 07:24 AM Apparently Martin Pfeiffer is offering samples of this material for his highest Patreon backer level. 12-Aug-20 07:24 AM Of course, Murphy’s Law, it probably is just parachute. 12-Aug-20 07:38 AM deuterated parachute? 12-Aug-20 07:38 AM For a 10 MT gravity bomb, that’s kind of a necessary component so the aircraft can get away. 12-Aug-20 11:04 AM huh, Marty's got some interesting toys 12-Aug-20 11:04 AM I think my trinitite sample + spherule came from his collection originally 12-Aug-20 11:16 AM ICP-MS or even XRF might still be interesting to look for heavier dopants/coatings 12-Aug-20 11:16 AM SXR optics shenanigans shrug 12-Aug-20 11:16 AM just a simple mass measurement might also reveal the subtle difference indicative of deuteration 12-Aug-20 11:32 AM just bombard it with deuterons and look for neutrons 12-Aug-20 11:32 AM also @qualia what are hugoniots? 12-Aug-20 11:35 AM the rankine-hugoniot jump condition describes the state of a material on both sides of a shock wave traveling through it 12-Aug-20 11:35 AM my 2:30am googling almost instantly brought up this very recently published compchem paper on shocks in ⁶LiD https://aip.scitation.org/doi/full/10.1063/5.0007714 12-Aug-20 11:36 AM yes, but I don't see the connection 12-Aug-20 11:37 AM 'bombs' 12-Aug-20 11:37 AM oh 12-Aug-20 11:37 AM yes 12-Aug-20 11:37 AM that's one way to cause a shockwave :D 12-Aug-20 11:59 AM https://www.youtube.com/watch?v=-p3YBCUwopU 12-Aug-20 12:05 PM Unfortunately we had to stop work on the ICP-MS and put it in storage before it was capable of doing analysis. 12-Aug-20 12:05 PM I hadn’t considered XRF. I figured if it was interstage material, dopants (say, Be?) would all be low Z hence invisible to XRF. 12-Aug-20 12:05 PM Some of the samples are slightly spicy, likely due to the U tamper and/or hohlrahm. I’d be interested in doing alpha spectroscopy, but that requires digestion, possible purification, and electrodeposition. 12-Aug-20 12:05 PM I’m not that confident in wet chemistry. 12-Aug-20 12:15 PM Only problem is it only can do transmission, and I don’t have a microtome to section this. I’ve got access to one with an ATR but it’s in Oregon 12-Aug-20 12:15 PM I wonder if there’s a way to do it by NMR... 12-Aug-20 12:25 PM https://www.sciencedirect.com/science/article/abs/pii/S0022311517300405 12-Aug-20 12:27 PM That’s interesting. 12-Aug-20 12:27 PM My friend just got two FTIRs. One is... kind of working but having issues? 12-Aug-20 12:27 PM It also has an input to an optical microscope. 12-Aug-20 12:27 PM The other may be newer, but I think we need to get software for it. 12-Aug-20 12:27 PM And on the subject of interstage, a humorous retweet: 12-Aug-20 12:27 PM https://twitter.com/gbrumfiel/status/1293550618255261696?s=21 12-Aug-20 01:17 PM Wonderful 12-Aug-20 01:17 PM All this reminds me I really need to figure out what the hell I want to do for my senior thesis... 12-Aug-20 02:01 PM oh man 12-Aug-20 02:01 PM I got some dried berries from the ukraine 12-Aug-20 02:01 PM dried and then cast into an energy pendant because that's the easiest way to get them as non-food into the EU 12-Aug-20 02:01 PM and well 12-Aug-20 02:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-88AA4.png 12-Aug-20 02:01 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3ADEE.png 12-Aug-20 02:02 PM Energy pendant? 12-Aug-20 02:02 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3D67D.png 12-Aug-20 02:02 PM And darn that’s a spike 12-Aug-20 02:02 PM Also you have really low background 12-Aug-20 02:03 PM Energy pendant just as a dumb joke, because of all those things containing thorium being sold by the chinese 12-Aug-20 02:03 PM Also you have really low background @Addison-110m 5 cm of lead in every direction 12-Aug-20 02:06 PM How many grams of berries? 12-Aug-20 02:06 PM Have you done any efficiency measurements? 12-Aug-20 02:07 PM the guy I got them from forgot to weigh them 12-Aug-20 02:07 PM and I don't have proper efficiency measurements in place yet, but I'm working on that 12-Aug-20 02:07 PM Were they from anywhere particular in Ukraine? 12-Aug-20 02:08 PM bought in a supermarket in kiev iirc 12-Aug-20 02:08 PM 5 cm of lead in every direction Even so seems decently low 12-Aug-20 02:09 PM well the first pic is just 250 seconds life time 12-Aug-20 02:09 PM Fair enough 12-Aug-20 02:09 PM we're not talking about low acitivity samples here 12-Aug-20 02:09 PM Also, still running just Maestro? 12-Aug-20 02:09 PM Random question: does the IAEA inspect civilian power reactors in nuclear weapons states? 12-Aug-20 02:10 PM it's more comfortable for every day use and I still didn't get to properly make my activity standard for gammavision 12-Aug-20 02:10 PM Is that directed at anyone specific? 12-Aug-20 02:10 PM once I got that going I can use gammavision better 12-Aug-20 02:10 PM Random question: does the IAEA inspect civilian power reactors in nuclear weapons states? @rdpierce yes 12-Aug-20 02:11 PM And ah, makes sense, good luck with figuring out a standard though, it’s nice to have a good efficiency cal 12-Aug-20 02:12 PM Yeah, I was wanting to turn that into Bq/kg berries. I figure you’ve got at least 2Pi losses, but efficiency is still an unknown, as is original mass of berries. 12-Aug-20 02:12 PM I’ve been arguing with several people who think the Soviet RBMKs were used for Pu production. 12-Aug-20 02:12 PM I don’t think so. 12-Aug-20 02:12 PM They certainly would be attractive for that purpose, given their ability to refuel while the reactor is running. 12-Aug-20 02:12 PM But I see a lot of issues. 12-Aug-20 02:15 PM I swore I recall it was designed so it could be used for that if needed 12-Aug-20 02:15 PM So I was wondering if the IAEA monitored them. It should be clear based on refueling frequency if they were intended for proliferation or not. 12-Aug-20 02:15 PM But USSR was a nuclear weapons state, so they had a right to produce Pu-239. 12-Aug-20 03:05 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Cs1-D5672.PNG 12-Aug-20 03:05 PM well that's fun 12-Aug-20 03:06 PM what's the deal with that spectrum? 12-Aug-20 03:06 PM Seems pretty good? 12-Aug-20 03:07 PM There's nothing particularly interesting about it I'm just still amazed at the Activity 12-Aug-20 03:08 PM Ah 12-Aug-20 03:17 PM Do you have a rough guess at mass 12-Aug-20 03:19 PM it's "one pack", so 100-250g I guess 12-Aug-20 03:19 PM Ah 12-Aug-20 03:19 PM A lot more than I figured for whatever reason 12-Aug-20 03:21 PM they've been dried, the weight of the whole pendant is ~70g 12-Aug-20 03:21 PM but we're approaching 1 kBq per kg wet mass 12-Aug-20 03:22 PM Was about to say that my powdered trinitite sample was only about 1cps for 137cs but it’s only 5g 12-Aug-20 03:22 PM I bet that also as a few more interesting peaks 12-Aug-20 03:23 PM Yeah, but overwhelmingly cesium 12-Aug-20 03:24 PM oh interesting 12-Aug-20 03:24 PM got a pic of the spectrum? 12-Aug-20 03:25 PM Give me a few minutes 12-Aug-20 03:42 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-0A7FF.png 12-Aug-20 03:42 PM there it is 12-Aug-20 03:44 PM @GigaSquirrel Sorry for the late reply, been camping. Lithium Deuteride’s controls are more for alkali metal hazards than anything else. Firefighters don’t like it when you tell them they can’t put wet stuff on the hot stuff until it’s cold stuff. 12-Aug-20 03:44 PM man, that compton peak alone shows how hot the Cs is 12-Aug-20 03:44 PM @funranium thanks for the info, I hope you had fun ^^ 12-Aug-20 04:09 PM That said, you might want to check the container it came in for identifying markings. "Special Form" can apply to more than just Special Nuclear Material (SNM). 12-Aug-20 04:09 PM If you see a serial number-like thing stamped anywhere that has the designation "AAA", some folks from the Department of Energy would be very happy to get that back from you. 13-Aug-20 04:19 AM I got my LaBr3 ❤️ 13-Aug-20 04:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8C801.png 13-Aug-20 04:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E0E20.png 13-Aug-20 04:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-14A24.png 13-Aug-20 04:19 AM I think I know why it was so "cheap" 13-Aug-20 04:19 AM but I don't care as long as it achieves the resolution 13-Aug-20 04:19 AM put together the PMT for it yesterday 13-Aug-20 04:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5ADE1.png 13-Aug-20 04:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-C14BE.png 13-Aug-20 04:24 AM Cool! 13-Aug-20 04:24 AM looking at PMTs also haha, but for visible light photon counting 13-Aug-20 04:24 AM thinking of a HV bias supply construction 13-Aug-20 04:25 AM an easy way for that are CCFL inverters actually! 13-Aug-20 04:25 AM yup! Looking at some on Aliexpress at the moment 13-Aug-20 04:25 AM https://www.aliexpress.com/item/32824572795.html?spm=a2g0o.productlist.0.0.eeac5b7ekmSkti&algo_pvid=5579f4b3-1eab-44df-b129-22ab14d6305c&algo_expid=5579f4b3-1eab-44df-b129-22ab14d6305c-7&btsid=0ab6d69f15973177451612323e338f&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_ 13-Aug-20 04:26 AM they're very linear to the input voltage 13-Aug-20 04:26 AM just keep in mind that you need a lot of filtering 13-Aug-20 04:26 AM shielding even 13-Aug-20 04:26 AM yep ^^ 13-Aug-20 04:27 AM my experiment will involve me communicating with my other team members over a distance 13-Aug-20 04:27 AM using radio 13-Aug-20 04:27 AM so we can do alignment of lasers, etc 13-Aug-20 04:27 AM I have encountered once 13-Aug-20 04:27 AM where the EMI from the lift motor room was enough to deafen my radio 13-Aug-20 04:27 AM so I will likely have to filter and shield these things 13-Aug-20 04:54 AM Badly shielded (usually by running unshielded cables, against the installation instructions) VFD's in lifts are reportedly really horrid RFI generators. 13-Aug-20 07:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-10FA3.png 13-Aug-20 07:37 AM slooowly it's growing! 13-Aug-20 07:49 AM also wow this thing is bright 13-Aug-20 07:49 AM the PMT is at 500V, that's a gain of 8*10³ 13-Aug-20 07:49 AM the amp behind it is at lowest gain of 2.5 13-Aug-20 09:10 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200813_180605-B36E0.jpg 13-Aug-20 09:10 AM glorious 3.3% fwhm @ 609 keV 13-Aug-20 10:01 AM god 13-Aug-20 10:01 AM i want one D: 13-Aug-20 10:01 AM Do you get much La self-background in it? 13-Aug-20 10:06 AM Stop making me want to pick up a project I totally cannot afford right now... 13-Aug-20 10:15 AM I have not done any Background measurenents yet 13-Aug-20 10:15 AM will do that over night 13-Aug-20 10:15 AM but La is pretty high Energy, 785 keV and around 1.4 MeV iirc 13-Aug-20 10:15 AM this is just small crystal, efficiency is terrible at those energies 13-Aug-20 10:15 AM best thing is 13-Aug-20 10:15 AM with the right pmt I should get another 0.7% better 13-Aug-20 10:18 AM How big is the crystal? 13-Aug-20 10:21 AM 20 mm diameter, 10 mm thickness 13-Aug-20 10:24 AM Wow that seems like a pretty decent amount of response from a fairly small crystal 13-Aug-20 10:25 AM It's pretty high density 13-Aug-20 10:25 AM but I also have a 185 kBq source ~7 cm from it 13-Aug-20 10:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200813_192902-66E3B.jpg 13-Aug-20 10:25 AM that's the lead xrf, the most active part of the spektrum 13-Aug-20 10:25 AM now I have a few kBq Th232 in there, let's see how well it handles the higher energy gammas 13-Aug-20 10:25 AM I want to see the separation of the two peaks around 950 keV 13-Aug-20 10:54 AM My LaBr RIID was my very favorite. Even though I have a 3x3 NaI now, which does work FAST though it weighs a ton, I could call spectra by eye and memory in the field with that LaBr unit usually by the 1min mark. 13-Aug-20 10:55 AM yep, the resolution makes up a lot of the missing efficiency 13-Aug-20 10:55 AM that's why I have the lowest detection limit on my hpge and not my well NaI, despite the higher efficiency 13-Aug-20 10:59 AM And then Canberra hands you an experimental unit, which becomes the Falcon 5000, and you wish you had a house to mortgage so that you could have it. 13-Aug-20 11:01 AM ohh what I would give for a non ln2 hpge 13-Aug-20 11:13 AM The Falcon is so much fun to play with. We could discriminate different batches of plutonium with it. Canberra will continually remind of the price tag everytime you touch it though. 13-Aug-20 11:15 AM yeah I figured 13-Aug-20 11:15 AM so it's properly low energy capable? 13-Aug-20 11:15 AM my hpge is blind below 50 keV 13-Aug-20 11:59 AM high energy works better than expected 13-Aug-20 11:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7F729.png 13-Aug-20 11:59 AM just look at the separation between the two peaks in the middle 13-Aug-20 11:59 AM they're 911 and 968 keV 13-Aug-20 11:59 AM down to the baseline 13-Aug-20 11:59 AM I'm sorry if you're getting tired of hearing about this detector but I am just so excited 13-Aug-20 12:02 PM i will never 13-Aug-20 12:05 PM energy linearity is also great 13-Aug-20 12:05 PM now I kinda already want a bigger one 13-Aug-20 12:06 PM heh 13-Aug-20 12:06 PM where'd you get it from? 13-Aug-20 12:07 PM https://www.ost-photonics.com/product-category/scintillation-crystal-2/labr3ce-scintillator/ 13-Aug-20 12:07 PM their NaIs are also surprisingly cheap 13-Aug-20 12:07 PM I think I'll ask them for a sponsor, some publicity on my twitter etc 13-Aug-20 12:07 PM because they're actually pretty affordable for the hobbyist 13-Aug-20 12:09 PM i was thinking maybe i could justify splurging on a big one like a 2x2 but uh.. heh 13-Aug-20 12:09 PM maybe not in LaBr3 13-Aug-20 12:10 PM Yep :v 13-Aug-20 12:10 PM they're about half of what I got quoted by berkley nucleonics / scionix 13-Aug-20 12:11 PM wow they have those little Muonwatch LYSO sticks for way cheap 13-Aug-20 12:11 PM yep! 13-Aug-20 12:11 PM also apparently they make each crystal on order so custon sizes should not be too expensive 13-Aug-20 12:11 PM Thank you very much for your order, I will arrange production tomorrow, the expected delivery date is August 7th. 13-Aug-20 12:11 PM I was asking for cutoffs, but sadly "they have none" 13-Aug-20 12:13 PM 2x2 NaI for $190 tho wow 13-Aug-20 12:13 PM yep! 13-Aug-20 12:13 PM I almost got a 40x40 NaI with the LaBr, just because they're so cheap 13-Aug-20 12:15 PM i'd like to get a PMT that neatly fits that nice little NaI you sent me and turn it into a portable detector, and free up my 3" RCA 8054 for somethin that justifies it a bit better 13-Aug-20 12:15 PM never did get that hamamatsu photon counter into a state suitable for MCA usage, ECL too weird 13-Aug-20 12:16 PM how'd that work? all photon counters I've seen so far were digital 13-Aug-20 12:18 PM @GigaSquirrel The Falcon was doing some discrimination down in the 20-30kV range. We were trying to disentangle Am & Pu X-rays. Good fun. Hope someone got a thesis out of it. 13-Aug-20 12:18 PM dang it now I want one even more 13-Aug-20 12:19 PM yeah it's a fast (100MHz-y iirc) digital differential signal that needs a weird transistor termination to read out properly, let alone turn it to e.g. TTL levels. i got a tube of strange ICs for doing that conversation and then lost it lmao 13-Aug-20 12:19 PM below ~80 keV LaBr actually has a worse resolution than NaI, but I haven't tested that yet 13-Aug-20 12:19 PM @qualia but it only outputs one pulse per photon, right? 13-Aug-20 12:20 PM ALSO like all ECL hardware it needs a ton of -6V current.. like 'active cooled LM7906’ kinda territory 13-Aug-20 12:20 PM in theory? 13-Aug-20 12:20 PM so for MCA usage you'd have to detect a pulse of individual photon pulses 13-Aug-20 12:20 PM which would be pretty hard I imagine 13-Aug-20 12:21 PM maybe? idk, maybe just need a delay line integrator or smth to widen out the time constant for an ADC 13-Aug-20 12:22 PM it would be an interesting undertaking, but imo it would be easier to take the PMT and use some different circuitry 13-Aug-20 12:23 PM also I love finding surplus uni hardware and looking it over & thinking 'This was definitely someone's phd project' 13-Aug-20 12:23 PM and then some other hardware is like 'this was definitely built by strung-out undergrads the night before it was due' 13-Aug-20 12:24 PM Oh yes 13-Aug-20 12:24 PM for a pmt for the small NaI you might want to ask iRad 13-Aug-20 12:53 PM hey @rdpierce know anything about converting that output from e.g. caget mca:adc1_mca1 -> mca:adc1_mca1 2048 0 0 1 3 8 13 22 [...] into something more .. standard? 13-Aug-20 12:53 PM I have no idea what Interspec/cambio is expecting out of a plaintext format 13-Aug-20 01:22 PM https://github.com/sandialabs/SpecUtils/blob/c7a26a847b812db3eb2eabdfe650a7d05c86fe7d/src/SpecFile_csv.cpp oh. oh god 13-Aug-20 01:44 PM time to measure intrinsic background 13-Aug-20 01:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-10253.png 13-Aug-20 01:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E061D.png 13-Aug-20 03:02 PM @qualia I’ve never used Interspec. It’s on my to do list. 13-Aug-20 03:02 PM I’ve also never tried to use ca_get to read raw spectrum data, but it seems likely to me that this is a vector of 2048 channels to follow, with each number being counts per bin. There almost certainly are docs for the format. 13-Aug-20 03:02 PM I use Mark Rivers’ IDL program for now. It can save a spectrum in text files that are very self-describing. 13-Aug-20 03:07 PM hmmm, okay. might need to go through the gyrations to get that'un going 13-Aug-20 03:07 PM and, you'd think so, right? but SpecUtils doesn't seem to actually document the plaintext formats.. 13-Aug-20 03:07 PM and the code seems to imply it wants txt/csv from, like, certain specific detectors. it's wonky 13-Aug-20 03:08 PM I’m talking about the format for the MCA EPICS record. 13-Aug-20 03:08 PM It has to be documented. 13-Aug-20 03:08 PM oh, sure, yeah. i know what that format is, I just want to turn it into N42 or PCF or whatever 13-Aug-20 03:08 PM You can also pull real time, live time, etc. 13-Aug-20 03:08 PM Well if they don’t document their formats, then you may be out of luck.... 13-Aug-20 03:08 PM Figuring how how to get data out of EPICS is easy. As for getting it into another package, that’s largely a function of the other package. 13-Aug-20 03:08 PM Don’t they have the equivalent of a CSV or one line per channel? 13-Aug-20 03:12 PM they claim to, but it also does all of these wonky heuristics to figure out what format it's in.. problem is InterSpec seemingly wants like fully formed data files out of a handheld/all-in-one analyzer unit, including stuff like detector model/serial numbers to lookup correction factors, etc 13-Aug-20 03:12 PM Surprisingly hard to just be like 'ok here is an array[2047] graph it plz' 13-Aug-20 03:26 PM @qualia You should check out Cambio 13-Aug-20 03:27 PM I am using Cambio 13-Aug-20 03:27 PM It converts all sorts of data formats into .spe or other formats that InterSpec will take 13-Aug-20 03:27 PM Then it should take .csv no? 13-Aug-20 03:27 PM InterSpec and Cambio both use the SpecUtils library to do conversions 13-Aug-20 03:27 PM It does, but .. it doesn't seem to like my 'here are just my bin values' CSVs. It seems to want/expecr certain formats of CSV 13-Aug-20 03:27 PM CSV isn't any kind of standardized thing anyways 13-Aug-20 03:27 PM e.g. qualia@wehnelt  ~/EPICS  cat pbcu.txt | sed 's/mca:aim1_adc1 2048 //' | tr -s '[:blank:]' ',' > pbcu.csv qualia@wehnelt  ~/EPICS  cut -c-100 pbcu.csv 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,6,7,7,208,314,319,315,321,317, qualia@wehnelt  ~/EPICS  13-Aug-20 03:30 PM Yeah, I just checked, Cambio takes .csv and convert to IAEA SPE or SPC format 13-Aug-20 03:30 PM pardon my completely goofy zero offset 13-Aug-20 03:30 PM My csv formatting is as simple as it gets: 13-Aug-20 03:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2BFD6.png 13-Aug-20 03:30 PM And that works for you? 13-Aug-20 03:30 PM HMM 13-Aug-20 03:31 PM Yep, saved straight from a python code 13-Aug-20 03:31 PM It also takes .csv directly as well, this file is the same one that I showed above 13-Aug-20 03:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E4254.png 13-Aug-20 03:31 PM It just can't load in metadata like live time, real time...etc. 13-Aug-20 03:31 PM And of course you'd have to make sure units are correct 13-Aug-20 03:41 PM !!!! 13-Aug-20 03:41 PM YEAH :D 13-Aug-20 03:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1597358485_20200813-150825-8FC0B.png 13-Aug-20 03:41 PM Oh my god tysm 13-Aug-20 03:41 PM this is totally wrong but it's progress 13-Aug-20 03:42 PM Have fun 13-Aug-20 03:42 PM I'd still load things into Cambio first to make sure things are right. But I often process these data with some analysis scripts I have, and it just turns out that .csv is the most convenient file format to use 13-Aug-20 03:43 PM my sloppy conversion incantation was cat pbcu.txt | sed 's/mca:aim1_adc1 2048 //' | tr -s '[:blank:]' '\n' | nl -s, -w1 -v0 | sed '1s;^;Channel,Data\n;' > pbcu.csv which can certainly be better/cleaner, and i'd love to get e.g. realtime/livetime data in there too 13-Aug-20 03:43 PM Yeah, I did the csv->pcf conversion with cambio 13-Aug-20 04:00 PM Worst case, you can manually put in real time and live time in Cambio 13-Aug-20 04:21 PM @qualia you’ve named your server wehnelt??? Awesome! 13-Aug-20 04:23 PM that's my laptop 13-Aug-20 04:23 PM The EPICS IOC host and lab sensor aggregator is analyzer 14-Aug-20 06:45 AM ohh I got an offer from someone at scionix 14-Aug-20 06:45 AM sigh 14-Aug-20 06:45 AM thanks, @Dyno ... 14-Aug-20 06:45 AM the offer was: If you are interested I have some [Japanese reactor incident] soil it will give a nice Cs-137 peak but also still some Cs-134 is visible but that is now slowly dying out, if you are interested I can send you a small sample. 14-Aug-20 10:08 AM That's legit neat. 14-Aug-20 10:08 AM Imo 14-Aug-20 10:21 AM oh yes 14-Aug-20 12:34 PM ooh 14-Aug-20 12:34 PM Weird Cesium 14-Aug-20 01:06 PM oh 14-Aug-20 01:06 PM my 14-Aug-20 01:06 PM god 14-Aug-20 01:06 PM https://shop.generationatomic.org/collections/melty-the-bear/products/short-sleeve-unisex-t-shirt-2 14-Aug-20 01:06 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B8273.png 14-Aug-20 01:06 PM look at it! 14-Aug-20 01:06 PM who would not want to save it 14-Aug-20 01:06 PM Ohhhhh my 14-Aug-20 01:08 PM I think it has something of old russian art / coat of arms 14-Aug-20 01:08 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/flat750x075f-pad750x1000f8f8f8-7C878.png 14-Aug-20 01:11 PM Krasnoyarsk. Marty loves that bear. 14-Aug-20 01:11 PM hehe 14-Aug-20 01:11 PM I mean it is a pretty cool coat of arms 14-Aug-20 01:28 PM there's a weird irony in a global warming t-shirt design not offering a tanktop 14-Aug-20 01:28 PM grumbles in lesbian 14-Aug-20 01:29 PM I was going to make a joke about the other pieces of clothing they have but this might not be the ideal place for it 14-Aug-20 01:47 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1EE98.png 14-Aug-20 01:51 PM wait 14-Aug-20 01:51 PM are tank tops associated with lesbians? 14-Aug-20 01:51 PM actually have been meaning to grab one of those Oakland Raycats shirts i've seen @funranium rockin' before 14-Aug-20 01:51 PM my graphic shirt wardrobe is very overdue for a nerdy refresh 14-Aug-20 01:51 PM and yeah kinda, like.. butch/futch lesbians specifically 14-Aug-20 01:52 PM Oakland raycats? 14-Aug-20 01:52 PM and yeah kinda, like.. butch/futch lesbians specifically Will second 14-Aug-20 01:53 PM https://store.dftba.com/products/oakland-raycats-shirt 14-Aug-20 01:54 PM Oh that is so cool 14-Aug-20 01:54 PM oh neat! 14-Aug-20 01:54 PM based off of the raycat meme thing, styled like a sports team logo 14-Aug-20 01:54 PM YEAH :3 14-Aug-20 01:54 PM its vrry good 14-Aug-20 01:55 PM I associate tank tops with people riding bikes and that's about it 14-Aug-20 01:55 PM raycat meme thing? 14-Aug-20 01:55 PM I assumed it was a sports team logo 14-Aug-20 01:55 PM rip my stereotype radar? 14-Aug-20 01:55 PM i like canonically temporarily turned my fursona green for a while after making & detecting my own x-rays because i'm a terrible irreverent nerd 14-Aug-20 01:55 PM sec 14-Aug-20 01:56 PM Wowwwwwww 14-Aug-20 01:56 PM Nerd alert 14-Aug-20 01:56 PM rip my stereotype radar? @idmb need to recalibrate that gaydar 14-Aug-20 01:56 PM Then again, here I am with radio antenna ear tufts 14-Aug-20 01:59 PM https://en.m.wikipedia.org/wiki/Human_Interference_Task_Force so it originated out of this (under Answers) as a proposed mechanism for keeping people away from nuclear waste sites, and the idea was you'd genetically engineer e.g. cats, to change color on exposure to ionizing radiation, while also establishing a cultural meme that your cat changing color is a bad omen that means you should leave this place 14-Aug-20 01:59 PM and a whoooole bunch of spinoff media has come out of this, because, well, it's kind of amazing 14-Aug-20 02:01 PM oh man that would indeed be awesome 14-Aug-20 02:03 PM "how do you unambiguously communicate extreme danger across a 10,000 year boundary?" guy in the back "FURRY DOOMSDAY TF CULT" 14-Aug-20 02:04 PM croud cheering 14-Aug-20 03:15 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Efad_YPXkAEaNdz-71E02.png 14-Aug-20 03:16 PM idly fantasizing but i wonder if the US DHS ever actually gets abolished if the market will suddenly flood with cheap ³He detectors 14-Aug-20 03:17 PM https://www.ebay.com/itm/174315736187 How much cheaper do you wish for 14-Aug-20 03:19 PM Well I mean, if you want to buy in that kinda bulk... 14-Aug-20 03:19 PM I may or may not have bought a 10-pack of those 14-Aug-20 03:19 PM I recall the answer being “may” 14-Aug-20 03:19 PM really i just want an array of position-sensitive detectors 14-Aug-20 03:19 PM but I would not go porportional here 14-Aug-20 03:20 PM or a little 6LiZnS converter screen 14-Aug-20 03:20 PM get yourself a 2D x-ray imager and a Li or Gd screen 14-Aug-20 03:20 PM yeah that ^ 14-Aug-20 03:20 PM i have the MCP already, and the position analyzer too 14-Aug-20 03:20 PM I was thinking more along the lines of a big CCD 14-Aug-20 03:20 PM I really ought to get a detector working before the end of next May if I want to build one 14-Aug-20 03:21 PM RAE encoders aren't fantastic for resolution but it'll do 14-Aug-20 03:21 PM yeah that could work too 14-Aug-20 03:21 PM grain size and transmission efficiency (so, thinness) of your converter plate make the difference for imaging tmk 14-Aug-20 03:22 PM (tmk?) 14-Aug-20 03:23 PM to my knowledge 14-Aug-20 03:23 PM ah! 14-Aug-20 03:23 PM I have not read much on imaging stuff yet, that's just the first thing I would have tried ^^ 14-Aug-20 07:11 PM Sadly, it is so very, very out of print. 14-Aug-20 07:11 PM WAIT WHAT IT'S COMING BACK?!?! 14-Aug-20 08:28 PM YAAAY 15-Aug-20 02:20 AM it rained! 15-Aug-20 02:20 AM first time in like three weeks 15-Aug-20 02:20 AM so naturally I collected some water and am now looking for Be7 15-Aug-20 02:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200815_105909-27556.jpg 15-Aug-20 02:20 AM turned out to be exactly one liter 18-Aug-20 12:46 AM there was none to be found 18-Aug-20 12:46 AM Unfortunately, our company has regulations that we cannot sponsor free crystals for our customers, I hope your understanding! But if you are willing to do some publicity for our products, we will be extremely grateful! 18-Aug-20 12:46 AM would have been too nice, but it never hurts to ask 18-Aug-20 08:54 AM oh man the new detector works 18-Aug-20 08:54 AM but the small crystal is a bit of a downside 18-Aug-20 08:54 AM 185 kBq Ra-226 at ~2 cm distance give just ~20% dead time on my MCA, with the NaI well it's 100% and a lot of smearing 18-Aug-20 11:14 AM https://www.ebay.de/itm/193610138249 THEY'RE BACK, BABY 18-Aug-20 11:15 AM oooh 18-Aug-20 11:15 AM d'ja ever get yours working? 18-Aug-20 11:18 AM I wanted to wait for the right connector, got that yesterday, but it turns out I ordered the wrong one 18-Aug-20 11:19 AM oops 18-Aug-20 11:20 AM and lately I've been working more with the LaBr 18-Aug-20 11:20 AM ordered 2, one for me, one for @Rbastler 18-Aug-20 11:38 AM THREE POINT TWO PERCENT 18-Aug-20 11:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-EE072.png 18-Aug-20 11:38 AM the reflectivity of my enclosure brought me a 3% improvement in resolution \o/ 18-Aug-20 12:29 PM https://www.ebay.de/itm/193610138249 THEY'RE BACK, BABY @GigaSquirrel I'll probably try to add a d-sub 9 pin 18-Aug-20 12:30 PM it just needs -12V iirc 18-Aug-20 12:30 PM ground, -12V and signal output 18-Aug-20 03:42 PM Does it include a detector? 18-Aug-20 03:42 PM What’s the spectrum like, considering I normally see alpha spec done in a vacuum chamber. 18-Aug-20 03:42 PM Also, alpha spec typically uses a biased amplifier, say, to map 3-5 or 4-8 MeV to a 0-10V NIM range. 18-Aug-20 03:42 PM I don’t see any controls. 18-Aug-20 05:43 PM i think it's just a detector 18-Aug-20 05:43 PM maybe a preamp board too? dunno 18-Aug-20 10:59 PM it's more of a counting sort of thing 18-Aug-20 10:59 PM 50 mm dia detector at a low bias voltage, not for spectroacopy but to discriminate alphas against betas & gammas 18-Aug-20 10:59 PM the circuit behind it is an amplifier and window comparator 18-Aug-20 10:59 PM it's for measuring wipe tests and air filters and the Likes 18-Aug-20 11:10 PM it will give low rez spectroscopic information, but in general it's just a fun, rugged silicon detector to play around with 18-Aug-20 11:10 PM coat it in Li or B and use the low Resolution to discriminate neutrons, something like that ^^ 19-Aug-20 06:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B60AF.png 19-Aug-20 06:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A96CB.png 19-Aug-20 06:40 AM For detection of alpha, beta and gamma radiation, type GS1 scintillator is recommended. Crushed and sized powders of GS1 are used in flow cells for counting alpha particles, and C-14 and other beta emitters in biomedical research and process control functions. 19-Aug-20 10:39 AM https://gigabecquerel.wordpress.com/2020/08/19/building-a-labr3ce-gamma-spectrometer/ 20-Aug-20 01:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2F230.png 20-Aug-20 01:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A739F.png 20-Aug-20 01:49 PM the difference in resolution is staggering 20-Aug-20 03:08 PM mmmmm 20-Aug-20 08:30 PM gimme.. 20-Aug-20 11:39 PM Come here and you can play with it all you want :P 20-Aug-20 11:39 PM I mean if you're interested, I could also build you a LaBr detector just like mine 20-Aug-20 11:53 PM @Rbastler can attest that my detectors are well built 21-Aug-20 12:01 AM do you happen to know how thick the aluminum casing around the crystal was from the manufacturer? 21-Aug-20 12:05 AM No, but I'm currentlly measuring ²⁴¹Am to compare the 26 and 59 keV peak, for calculating the total absorption before the crystal 21-Aug-20 02:32 AM The HPGe seems to blow the other two away 21-Aug-20 02:35 AM oh easily 21-Aug-20 02:41 AM Do you need to always keep it cool? Or just the days you want to use it? 21-Aug-20 02:41 AM $2 a day seems pretty cheap, though the lag of chilling it (from warm, when you want to use it NOW) sounds lame 21-Aug-20 03:21 AM cooling it down takes a lot of nitrogen, so I prefer to just keep it cold, if possible 21-Aug-20 03:21 AM $2 a day doesn't sound too bad, but it quickly adds up and it's often not worth if when I don't have to measure something 21-Aug-20 03:21 AM I can let it warm up without taking damage, thankfully 21-Aug-20 08:15 AM No, but I'm currentlly measuring ²⁴¹Am to compare the 26 and 59 keV peak, for calculating the total absorption before the crystal As it turns out my Al is a few negative mm thick 21-Aug-20 08:15 AM all the scattering and whatnot gives me a higher value for the 26 keV peak than should be possible, my peak is about twice as big as should be possible with the different emission probabilities 21-Aug-20 08:15 AM it's all scattering and other continua that lift it 21-Aug-20 08:15 AM and there are too many peaks for my software to find the baseline 21-Aug-20 08:15 AM now how do I prevent that 21-Aug-20 08:15 AM let's try plastic that's always a good way to get rid of low energy stuff 21-Aug-20 11:04 AM dang it 21-Aug-20 11:04 AM I have now made sure that there is no scattering from the suroundings, the spectrum is way cleaner, but the peak height ratio is still very much out of whack 21-Aug-20 11:04 AM I was hoping that I can go by height alone, but apparently the resolution suffers at the low end and I have to go by area 21-Aug-20 11:04 AM but there are too many overlapping peaks to accurately tell where one starts and the other one ends 21-Aug-20 11:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200821_201933-6353A.jpg 21-Aug-20 11:21 AM that's my setup, the source was behind the orange plexi 21-Aug-20 11:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200821_201821-8D27E.jpg 21-Aug-20 11:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200821_201856-5CBE4.jpg 21-Aug-20 01:34 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200821_223401_241-CAAED.jpg 21-Aug-20 02:07 PM Nice! 22-Aug-20 02:30 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B02D7.png 22-Aug-20 05:46 AM Oh dang 22-Aug-20 05:46 AM I might get another HPGe 22-Aug-20 05:46 AM tiny 10 or 15% one, with a Be window 23-Aug-20 07:56 AM Yeah, HPGe’s are not terribly sensitive on the low end due to the need for a high vacuum enclosure for then cryostat, typically made from thick Al. 23-Aug-20 07:57 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200823_093350_1-5E1DC.jpg 23-Aug-20 07:57 AM I have a well type HPGe. Just setting a Cs-137 source on top of the housing doesn’t result in any 32 keV x-ray peak. 23-Aug-20 07:58 AM the Al is not as much of an issue but the contact 23-Aug-20 07:58 AM Oh damn 23-Aug-20 07:58 AM Nice 23-Aug-20 07:58 AM that's why all low energy ones are P type 23-Aug-20 07:58 AM that one doesn't show any microphonics, indicating a dead frontend fet 23-Aug-20 07:58 AM but that can be replaced 23-Aug-20 07:59 AM Can it be replaced without breaking the vacuum? 23-Aug-20 07:59 AM What I realized is that the NP boundary is cylindrical, and there’s no direct LOS to it. 23-Aug-20 07:59 AM Can it be replaced without breaking the vacuum? @Addison-110m Nope! 23-Aug-20 07:59 AM Oh funnn 23-Aug-20 08:00 AM What I realized is that the NP boundary is cylindrical, and there’s no direct LOS to it. @rdpierce What NP boundary? There is none, as it's PIN 23-Aug-20 08:00 AM The Al in the well is supposedly thinner so I believe I can get a 32 keV peak if I just stick the sample inside. 23-Aug-20 08:00 AM Ok sorry, my mistake. The sensitive part is cylindrical. 23-Aug-20 08:00 AM Oh funnn @Addison-110m Eh, it's doable :D The rule of thumb is that the crystal can be in air for ~10 minutes without taking any damage 23-Aug-20 08:01 AM Where did you hear that? 23-Aug-20 08:01 AM About crystal damage in air? 23-Aug-20 08:02 AM The Al in the well is supposedly thinner so I believe I can get a 32 keV peak if I just stick the sample inside. @rdpierce The Al is not the issue, 32 keV has a halv value layer of 2.8 mm in al, but only 110 µm in Ge, and the dead layer on the N of your PIN is usually a few 100 µm thick 23-Aug-20 08:02 AM Where did you hear that? @rdpierce From a few folks repairing detectors, like our common friend 23-Aug-20 08:03 AM Oh that’s interesting..... 23-Aug-20 08:03 AM So the issue isn’t aluminum, it’s Ge shielding itself, so I can only measure it if I’m inside the cylinder? 23-Aug-20 08:05 AM Yep! 23-Aug-20 08:05 AM assuming the crystal is built in a way to detct low energy stuff 23-Aug-20 08:05 AM Thank you! I’ve been puzzling about that. 23-Aug-20 08:06 AM what's its well diameter? 23-Aug-20 08:07 AM No, I got this detector from our mutual friend. He showed me a spectrum of Chernobyl fission products, and it had a distinct 32 keV peak. So I believe him. My Cs-137 check source can’t fit in the well. He took that spectrum with the sample in a tube in the well. 23-Aug-20 08:07 AM Well diameter is about 10 mm 23-Aug-20 08:09 AM ah, great 23-Aug-20 08:11 AM Also, a friend at a lab had a licensed X-ray source that I think was at least 100 uCi. It had an energy in the 20-25 keV range. It had to be external as we couldn’t fit it in the well. I caught a small peak with that. Fire enough bullets and one will get through. So I think the crystal is definitely sensitive if I can get the sample into the well. I need to find <10 mm plastic sample vials. 23-Aug-20 08:12 AM https://www.lacontainerstore.com/Polyvials%C2%AE_c_13.html Are good if kinda pricy 23-Aug-20 08:12 AM They’re what the reactor uses for in core stuff 23-Aug-20 08:13 AM oh neat 23-Aug-20 08:13 AM A well HPGe would be nice, my only well detector is NaI 23-Aug-20 08:15 AM I need to get my well NaI detector working but I think I’m going to try and validate the other hardware with good crystals first 23-Aug-20 08:20 AM Bookmarked. Thanks @Addison-110m 23-Aug-20 08:20 AM Hope it’s useful 23-Aug-20 08:21 AM I have an NaI well that I bought for $25 as a random lot in a medical auction. 23-Aug-20 08:21 AM Oh, what’s it look like 23-Aug-20 08:21 AM Because I think mine is also old medical stuff 23-Aug-20 08:22 AM Also included a bunch of hernia repair surgical kits. 23-Aug-20 08:22 AM Lmfao 23-Aug-20 08:24 AM https://twitter.com/ryanpierce_chi/status/767082263855202304?s=21 23-Aug-20 08:24 AM https://twitter.com/ryanpierce_chi/status/767084273853693954?s=21 23-Aug-20 08:24 AM Oh that’s nice 23-Aug-20 08:24 AM Mine is nothing near that fancy 23-Aug-20 08:26 AM Got it at a medical auction. My friend took me along to flag interesting stuff. This was bundled in a misc lot because nobody knew what it was. I recognized it and flagged it for bidding. 23-Aug-20 08:26 AM It included a janky SCA. 23-Aug-20 08:26 AM Signal and power connect via an XLR. 23-Aug-20 08:26 AM At least it uses SHV for high voltage. 23-Aug-20 08:27 AM Can’t anyone just use that connector for microphones... 23-Aug-20 08:27 AM There’s some kind of preamp and voltage divider in the base. 23-Aug-20 08:28 AM The one I have has something similar, it’s only 1 in in diameter though 23-Aug-20 08:28 AM In order to use it, I have to turn the castle sideways and use an Ortec preamp base with my NIM gear. 23-Aug-20 08:28 AM Long term project: Build a preamp for it that fits in its original base, but takes NIM power via a DE-9 and has a BNC for signal out. So it can be used upright as intended with NIM gear. 23-Aug-20 08:37 AM Oh that’d be cool 23-Aug-20 08:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_9143-65ADD.JPG 23-Aug-20 08:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_9144-D7DC2.JPG 23-Aug-20 08:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_9147-A0C7D.JPG 23-Aug-20 08:39 AM I’m looking at reverse engineering an existing preamp and just laying out a differently shaped board. 23-Aug-20 08:40 AM Makes sense 23-Aug-20 08:40 AM Also, damnit discord 23-Aug-20 08:51 AM hahahahaha 23-Aug-20 08:51 AM I just saw those NaI well pics 23-Aug-20 08:51 AM that's exactly how I got mine 23-Aug-20 08:51 AM found the lead pig with 2x2 NaI inside at the scrap yard 23-Aug-20 08:52 AM Oh nice 23-Aug-20 08:52 AM Well, flights taking off, see y’all later 23-Aug-20 08:52 AM See ya! 23-Aug-20 08:52 AM also lol 23-Aug-20 08:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-54057.png 23-Aug-20 11:07 AM And a Good Orb to you! 24-Aug-20 06:10 AM I randomly found this video browsing the Burroughs Wellcome collection and I think it definitely belongs here: 24-Aug-20 06:10 AM https://www.youtube.com/watch?v=k7xcurv-6DQ 24-Aug-20 06:10 AM “If you are unable to obtain these [soft x-ray] aluminium filters from the manufacturer you can easily make them. Obtain an aluminium cookie sheet that is marked pure or commercially pure aluminium…” 24-Aug-20 06:10 AM paging @funranium 24-Aug-20 06:14 AM I don't see the issue tbh 24-Aug-20 06:14 AM Al is Al and if you calculate the thickness right 24-Aug-20 06:16 AM The main issue I see is trusting dentists to modify their own equipment 24-Aug-20 06:16 AM But they do actually show how to test heads so you aren't too likely to screw up 24-Aug-20 06:17 AM The main issue I see is trusting dentists to modify their own equipment @PeterC fair, that is an issue 24-Aug-20 06:17 AM The cookie sheet as an Al source still cracks me up 24-Aug-20 06:18 AM :D 24-Aug-20 10:31 AM It works and many of the older dentists and veterinarians I've met, particularly the rural ones, have the technical chops to do field repair. They are properly hesitant about it due to the human use/certification bit. Vets don't have that worry. 24-Aug-20 10:41 AM Here old medical gear meant to humans goes to vets quite often 24-Aug-20 10:41 AM So sometimes people encounter stuff like x-ray machines from the fifties at vet's 24-Aug-20 10:58 AM The x-ray head at my childhood dentist was a Korean War field unit. I wandered in last year just to see. It's still there and still being used, though with digital bitewings. 24-Aug-20 11:14 AM Nice 24-Aug-20 06:44 PM My dentist has old GE units. The little sound they make is burned Into memory as I have been going there pretty much all 40 years of my life. 26-Aug-20 06:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4A262.png 26-Aug-20 06:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7AA93.png 26-Aug-20 06:24 AM my dirt sample from a japanese place arived 26-Aug-20 06:24 AM the name of the place is apparently an insult 26-Aug-20 07:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200826_155018-FD4C1.jpg 26-Aug-20 07:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200826_154849-1E85B.jpg 26-Aug-20 07:08 AM bit of cesium in there 26-Aug-20 07:08 AM the two big peaks are ¹³⁷Cs, that's "boring" as it was to be expected 26-Aug-20 07:08 AM just left of the red peak is a smaller peak growing, pretty sure that's ¹³⁴Cs 26-Aug-20 07:08 AM also expected but interesting, as I've never seen that before 26-Aug-20 07:30 AM Interesting! 26-Aug-20 07:30 AM also I have a question - how do you know the energy in keV? 26-Aug-20 07:30 AM where do you read that off? 26-Aug-20 07:31 AM calibration is easy, for most intents of purposes it's a linear function, you tell it with 2 to 3 known peaks what slope it has and the software calculates the rest 26-Aug-20 07:32 AM I see 26-Aug-20 02:42 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8D144.png 26-Aug-20 02:42 PM such a textbook spectrum 26-Aug-20 02:42 PM This was the same sample a few years ago 26-Aug-20 02:42 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Fukushima_soil_test-FAB0E.pdf 27-Aug-20 12:35 PM https://twitter.com/nuclearkatie/status/1298959142397325312 27-Aug-20 12:35 PM also ugh 27-Aug-20 12:35 PM my spectrometer is plagued by drift 27-Aug-20 12:35 PM it's the old preamp, I swapped wit with a DIY one and hope it will work better 28-Aug-20 01:43 AM ayy I got minimal drift 28-Aug-20 01:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-18813.png 28-Aug-20 01:43 AM also hpge spectrum 28-Aug-20 01:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-99E78.png 28-Aug-20 01:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6E39D.png 28-Aug-20 01:43 AM ¹³⁴Cs is a wonderful source to test a detector with those closely spaced lines 28-Aug-20 02:52 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CEDAA.png 28-Aug-20 02:52 AM techincally this is a double rainbow, right? 28-Aug-20 03:39 AM Maybe dumb question, but why there is such difference in background levels around that huge peak? 28-Aug-20 03:42 AM that's not background, but backscattering etc, it gives a continuum with a maximum energy of the actual peak 28-Aug-20 03:42 AM the other peaks have the same, but it's not as visible because they're not learly as strong 29-Aug-20 05:14 AM https://www.gammaspectacular.com/phpBB3/viewtopic.php?f=5&t=844 30-Aug-20 07:19 AM https://www.youtube.com/watch?v=7uqSCKRKZF0 Quick and dirty alpha detector 30-Aug-20 08:27 AM Katie rocks my world. 30-Aug-20 01:56 PM You always have the best background tunes :D 30-Aug-20 02:12 PM Not only my radiation is high energy >:) 30-Aug-20 02:12 PM https://www.youtube.com/watch?v=_DFHEqki47Y Must have been this, I think 30-Aug-20 02:58 PM That might be really useful as a demo detector for reactor lectures 30-Aug-20 03:05 PM ty for the link 30-Aug-20 10:47 PM https://www.youtube.com/watch?v=KdfHVcU8U7U 30-Aug-20 10:59 PM That might be really useful as a demo detector for reactor lectures @Addison-110m It's a really fun demonstration, not as nice looking as a cloud chamber, but great for explaining how geiger counters work 31-Aug-20 01:11 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200831_100752-B80F2.jpg 31-Aug-20 01:27 AM April 3rd? 31-Aug-20 01:29 AM so it has to be true, right? :P 31-Aug-20 02:05 AM Lolwat 31-Aug-20 07:46 AM funny looking magic wand 31-Aug-20 07:46 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/cdznte_01-CB419.png 31-Aug-20 08:16 AM I was thinking about this 31-Aug-20 08:16 AM @GigaSquirrel you've soil samples from right - how would you deal with disposing them 31-Aug-20 08:18 AM their activity is low enough to throw them in household trash 31-Aug-20 08:18 AM oh 31-Aug-20 08:18 AM keep in mind, we're talking about a dose rate that does not register on a geiger counter 31-Aug-20 08:19 AM so it needs a more sensitive piece of equipment like the scintillator you've built to detect the radiation from them? 31-Aug-20 08:19 AM yep 31-Aug-20 08:19 AM I see 31-Aug-20 08:19 AM I'd assume that would be the same for the sealed Am-241 sources in ionizing smoke detectors 31-Aug-20 08:20 AM In smoke detectors yes 31-Aug-20 08:20 AM if I had something really active I wanted to dispose of I'd go to our local envioremental protection agency, they're the ones with the yellow barrels 31-Aug-20 08:21 AM If they aren’t in detectors, while other story 31-Aug-20 08:21 AM Also, sorry, but that’s a cursed detector you’ve got there 31-Aug-20 08:21 AM I'd assume that would be the same for the sealed Am-241 sources in ionizing smoke detectors @SleepyOwl Joyce those can get into a dangerous range if handeled badly, which is why there are strong laws against opening the detectors 31-Aug-20 08:21 AM Also, sorry, but that’s a cursed detector you’ve got there @Addison-110m the wand or the sparky thingy? 31-Aug-20 08:22 AM Wand 31-Aug-20 08:22 AM yep 31-Aug-20 08:22 AM https://www.gbs-elektronik.de/posts/cdznte-detectors-28.php 31-Aug-20 08:23 AM I see 31-Aug-20 08:23 AM Neutron detector - interesting 31-Aug-20 08:25 AM neutron detectors are a lot of fun to play with 31-Aug-20 08:35 AM I’m really kicking myself still for not getting a neutron scintillator when I had the chance 31-Aug-20 08:37 AM what type? 31-Aug-20 08:38 AM There were the ones pulled from gr-135’s available last summer on eBay if I remember correctly 31-Aug-20 08:39 AM ah, those tiny LiI ones! 31-Aug-20 08:39 AM Yeah those 31-Aug-20 08:39 AM I have two, and both have pins ripped of, that seems to be a common failure mode 31-Aug-20 08:39 AM Ouch 31-Aug-20 08:39 AM never got aroud testing them 31-Aug-20 11:35 AM saaame here 31-Aug-20 11:35 AM sorta wanna make something with pogo pins and a little mounting jig for it 31-Aug-20 11:35 AM someday 31-Aug-20 11:35 AM i think one of mine still has the pins intact but they're, like, look-at-them-and-they-fall-off fragile 31-Aug-20 11:35 AM my biggest gripe about ben's video is that there's never going to be a SDD on ebay again for less than $1k 31-Aug-20 11:35 AM not that there were ever very many to begin with 31-Aug-20 11:39 AM yes 31-Aug-20 11:39 AM ALSO: a mechanical sticky pad on a fast linear actuator in vacuum to generate x-rays is adorable actually 31-Aug-20 11:40 AM also yes 31-Aug-20 11:40 AM a friend of mine actually managed to get x-rays from tape 31-Aug-20 11:40 AM https://www.youtube.com/watch?v=U0PFo7PU5pE 31-Aug-20 11:40 AM that's how I got to know him, through this video 31-Aug-20 11:45 AM ah, short & sweet 31-Aug-20 11:45 AM powerdrilling a rotary feedthrough on what looks like a freestanding turbo.. brave 31-Aug-20 11:47 AM probably a drag pump? I hope? 31-Aug-20 11:47 AM I like the two-clamps-is-enough 31-Aug-20 11:48 AM nope, turbo 31-Aug-20 12:21 PM @qualia This guy is an SDD from an XRF gun, with a preamp in it I assume... The problem is no data on it is available https://www.ebay.com/itm/OXFORD-Detector-x-ray-Parts-51-4104914-51-4105854-792/174174386367 31-Aug-20 12:21 PM There used to be $500 SDDs in good condition and $300 SDDs with damaged window, but I was too poor to get them when they were up 31-Aug-20 12:24 PM yeah ;c 31-Aug-20 12:27 PM A teardown pic from one of the XRF gun repair shops in China, this particular shop wasn't keen on selling parts to people they don't know though 31-Aug-20 12:27 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-893E5.png 31-Aug-20 12:27 PM And they just completely ghosted me when I asked about that tiny x-ray tube 31-Aug-20 12:30 PM I wonder what target bens tube is using, if they use silver to filter why not use a silver anode to begin with? 31-Aug-20 12:39 PM You still want high efficiency x-ray conversion at the target, given that there is severe current on target limitations in a handheld device 31-Aug-20 12:39 PM Not sure what the target material is specifically, but I'd imagine something higher Z than silver 31-Aug-20 12:40 PM so it's more of a density thing than a spectrum thing 31-Aug-20 12:41 PM a silver anode will still have a bunch of continuum radiation without filtration, too 31-Aug-20 12:43 PM Well more of an atomic weight kind of thing... You want lots of bremsstrahlung with as broad of a spectrum as possible, with silver as the target I'd imagine you won't have sufficient intensity at those higher energies 31-Aug-20 12:47 PM right, yeah 31-Aug-20 12:48 PM Can you make EPICS control the hardware functions for the Canberra MCAs? Specifically I'm looking at the desktop InSpector series MCAs. Obviously I don't have Genie 2K... @qualia 31-Aug-20 12:48 PM https://www.ebay.com/itm/Canberra-Desktop-InSpector-Multi-Channel-Analyzer-Model-1200/133496398160 31-Aug-20 12:49 PM afaik it only works for the 556 aim 31-Aug-20 12:49 PM heh, I've got one MCA just like this, looking for a way to make it run 31-Aug-20 12:49 PM I even have genie 2k, but no dongle 31-Aug-20 12:50 PM https://cars.uchicago.edu/software/epics/mca.html 31-Aug-20 12:50 PM doesn't look like it, unfortunately 31-Aug-20 12:52 PM Well maybe we can hope the serial protocols are very similar between this and the DSA-2000? 31-Aug-20 12:53 PM mmmmmaybe 31-Aug-20 12:53 PM the ND556 AIM works over ethernet, not serial 31-Aug-20 12:53 PM via ethernet frames, no less 31-Aug-20 12:54 PM Ah that's annoying 31-Aug-20 12:55 PM yeah ;c 31-Aug-20 12:55 PM sry 31-Aug-20 12:55 PM shame canberra's such a hardass about handing out software 31-Aug-20 12:57 PM worst thing is 31-Aug-20 12:57 PM the new versions of g2k start without the dongle 31-Aug-20 12:57 PM no error message nothing 31-Aug-20 12:57 PM you can open an read spectra files, do everything the software can 31-Aug-20 12:57 PM you can open the menue to add an MCA 31-Aug-20 12:58 PM AND THE DIPSH... JUST MAKE IT LOOK LIKE NOTHING IS CONNECTED 31-Aug-20 12:58 PM I SPEND DAYS FIGURING OUT WHY THE F MY MCA IS NOT WORKING 31-Aug-20 12:58 PM it's working perfectly 31-Aug-20 12:58 PM but my genie is sulking and doesn't want to talk to it 31-Aug-20 12:59 PM This sounds like a task for the Reverse Engineering discord 31-Aug-20 12:59 PM Though hardware keys are notoriously difficult things... I doubt many people who owns such a key would be willing to give their copy up for the greater good 31-Aug-20 01:02 PM I mean I can probably supply the software, but no dongle 31-Aug-20 02:58 PM Oh how I’ve missed these detectors 31-Aug-20 02:58 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-7CF38.jpg 31-Aug-20 06:02 PM friends detected 31-Aug-20 08:25 PM Their name is robie, they’re a good detector 31-Aug-20 10:09 PM The scotch tape x-ray generator is a trick that smart*ss physics undergrads tried once to try to show they were smarter than the safety people. The rest of the safety people backed away as I wandered over to the office supplies, grabbed all the rolls of tape, a sharpie, and told them "Give each roll a serial number and complete a radiation use authorization application for each one. We'll need to register them as well, so I'll let your PI know how much this is going to run her." PI, on hearing of this, facepalmed and ordered them to do as they were just instructed. Valuable life lessons were learned that day. If you want to play the letter of the law game you should probably learn the rules first. 31-Aug-20 10:09 PM It is now part of the Physics Dept. lore: "Just because you saw it on Youtube does not mean it is a good idea nor should you try to do it on campus without checking with your PI first." 01-Sep-20 05:03 AM teehee 01-Sep-20 05:03 AM Speaking of detectors 01-Sep-20 05:03 AM (I know, complete surprise coming from me) 01-Sep-20 05:03 AM @Addison-110m didn't you think / talk about making your own scintillators? 01-Sep-20 05:03 AM A friend of mine will produce some "SCTF-MAPbBr3" and I vaguely remember you posting some Paper about them or sth similar 01-Sep-20 05:03 AM complaining about the nasty stuff in solutions 01-Sep-20 05:46 AM wish i could make the part of my brain that's constantly looking to squirm around the letter of the law re: radiation experiments calm the hell down 01-Sep-20 05:46 AM cali's so aggro and most of my ideas are too big for my own good 01-Sep-20 05:46 AM sad trombone 01-Sep-20 07:38 AM Yeah I did! The issues I ran into ended up being that the solvent used in most of the papers I’d read is a GHB analog and illegal in a more than a few states 01-Sep-20 07:48 AM Yikes 01-Sep-20 07:48 AM do you have any papers on those scintillators? 01-Sep-20 07:48 AM all I know is high light yield at cryo temps and sub ns decay time 01-Sep-20 07:50 AM I think these weren’t necessarily being used as scintillators but semiconductors 01-Sep-20 07:51 AM oh, hm 01-Sep-20 07:51 AM guess I'll see what I get from him :D 01-Sep-20 07:51 AM I didn’t read as much about them being used as scintillators 01-Sep-20 07:52 AM he might also be mixing up some things 01-Sep-20 07:52 AM coming to think of it sub ns timing would be close to Impossible with PMTs, not sure about SIPMs 01-Sep-20 08:17 AM SiPMs might be faster because there's no dynode chain 01-Sep-20 08:17 AM vacuum photodiodes and MCPs have sub-ns timing properties 01-Sep-20 08:20 AM does the dynode chain limit bandwidth? 01-Sep-20 08:20 AM I thought it only introduces delay 01-Sep-20 08:22 AM delay and jitter iirc 01-Sep-20 08:22 AM MCPs are essentially a dynode chain but the total multiplicative transit length is on the order of mm vs cm 01-Sep-20 08:22 AM so less jitter, i think 01-Sep-20 08:24 AM fair 01-Sep-20 08:30 AM if you're feeling patient, you can use your ambient neutron background to roughly characterize the response time of a completely blanked-off pmt 01-Sep-20 08:30 AM been meaning to try that one out for a while 01-Sep-20 08:48 AM also once read a paper about surrounding a NaI scintillator with a bunch of water to turn it into a neutron detector and i'm surprised that technique doesn't get brought up more 01-Sep-20 08:49 AM SiPMs are known for their extremely fast timing resolutions, sub-ns will be tough though, mainly due to the preamps requirements and just front end analog design in general 01-Sep-20 08:49 AM I've read several papers that measures the time-of-flight of light pulses down optical fibers using SiPMs. Here's an example of the result of measuring scintillation light pulses 01-Sep-20 08:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6FE01.png 01-Sep-20 08:49 AM I think better resolution was definitely possible, there are too many factors that could introduce sub-ns jitters, like signal reflection from the fiber, the fact that the pulse is not truly Gaussian...etc. 01-Sep-20 10:53 AM https://pubs.acs.org/doi/abs/10.1021/acsphotonics.8b00873 @GigaSquirrel 01-Sep-20 10:48 PM Cool, thanks! 03-Sep-20 06:43 AM has anyone here got experience with the red pytaja? 03-Sep-20 06:43 AM http://pavel-demin.github.io/red-pitaya-notes/mcpha/ This looks very nice 03-Sep-20 08:31 AM It seems that this is the next best option, but the 16-bit ADC version is still really expensive, and I wonder if there will be any significant difference between the 16 bit and 14 bit version 03-Sep-20 08:33 AM I went with the 14bit variant, as a friend of mine wanted to sell his and I only need 4k channels for my scintillators 03-Sep-20 08:33 AM HPGe isn't portable 03-Sep-20 08:33 AM Another concern I would have is conversion deadtime and stability of the ADC 03-Sep-20 08:34 AM I mean it's still better than going over the soundcard, which would be my alternative for portable stuff 03-Sep-20 08:34 AM I think the Xynq is pretty fast at pulse height processing, if the pulse height processing is actually well implemented in the FPGA part of the chip 03-Sep-20 08:35 AM yep! 03-Sep-20 08:35 AM It seems most modern 8k channel all-digital MCAs have at least 16-bit ADCs 03-Sep-20 08:43 AM What MCA do you use for your HPGe then? 03-Sep-20 08:46 AM an ancient ortec isa card 03-Sep-20 08:46 AM 916 iirc? 03-Sep-20 08:46 AM I mean it still works great at what it does 03-Sep-20 08:46 AM but an ISA computer is far from portable 04-Sep-20 03:36 AM ordered some SiPM 04-Sep-20 03:36 AM from ketek 04-Sep-20 04:37 AM yay! 04-Sep-20 04:54 AM \o/ 04-Sep-20 07:33 AM what price / size? 04-Sep-20 09:23 AM https://www.ketek.net/store/category/sipm-standard-devices/ 04-Sep-20 09:23 AM pm1125, pm3315 and pm3325 04-Sep-20 09:23 AM relatively cheap compared with hamamatsu pin diodes 04-Sep-20 09:23 AM I mean they are in the same price range 04-Sep-20 09:59 AM keep the channel updated on how those work? i looked at those ages ago but got busy on other projects...their prices have come down quite a bit since then too 04-Sep-20 10:21 AM will do 04-Sep-20 10:31 PM Looking back the thread, yeah, EPICS is very limited in the hardware it supports. It’s frankly a miracle Mark Rivers got enough info on some existing products to code what he did. 04-Sep-20 10:31 PM Extending it to other ICB NIM modules may be doable. 04-Sep-20 11:44 PM that weird serial canberra hardware is just asking for someone to come along with a logic analyzer and rip it apart 07-Sep-20 03:29 AM https://bib-pubdb1.desy.de/record/416291/files/lockmann_hh_alliance18_online.pdf Well that's a new one (for me at least) 07-Sep-20 05:44 PM terahertz radiation is still such strange voodoo to me 07-Sep-20 05:44 PM that is an undeniably beautiful detector though 07-Sep-20 05:44 PM strange little rainbow crystal calorimeters 07-Sep-20 11:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-C4CAD.png 07-Sep-20 11:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-00F8D.png 07-Sep-20 11:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-79A7D.png 07-Sep-20 11:07 PM I love this PCB 07-Sep-20 11:07 PM Cremat preamp (missing) to read the detector signal, single ended to differential and then cable drivers 07-Sep-20 11:07 PM I have another PCB here for rackmount, differential to single ended and place for cremat shapers 07-Sep-20 11:42 PM Cremat preamp (missing) to read the detector signal, single ended to differential and then cable drivers Times 30 of course, one per detector 08-Sep-20 01:32 AM I really like this delay like approach, never seen that before 08-Sep-20 01:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-44581.png 08-Sep-20 01:32 AM only one amp per cathode and just measure amplitude to get position information 08-Sep-20 10:42 AM makes sense 08-Sep-20 10:45 AM oh yeah, MCPs seemingly use thay kind of delayline detector all the time 08-Sep-20 10:45 AM works well with their fast transit time 08-Sep-20 10:46 AM this makes me want to build one even more 08-Sep-20 10:46 AM You can do better: http://www.roentdek.de/info/Delay_Line/ 08-Sep-20 10:47 AM that same kind of delay line position resolving amp chain will also let you use position sensitive gas proportional counters tmk 08-Sep-20 10:47 AM position sensitive 3He, etc 08-Sep-20 10:47 AM aren't those resistive? 08-Sep-20 10:48 AM but these are nicer : 08-Sep-20 10:48 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Schematic-layout-of-an-MCP-Chevron-stack-w-74C47.png 08-Sep-20 10:48 AM oh wow nice 08-Sep-20 10:49 AM The phosphor is super bright, you can see individual ion hits by eye 08-Sep-20 10:49 AM i would love to find a transparent phosphor-coated screen for this and many other applications 08-Sep-20 10:49 AM just the screen 08-Sep-20 10:49 AM they're pretty easy to bleach / make useless 08-Sep-20 10:49 AM but this is basically what we buy: 08-Sep-20 10:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1dvqDKYFUjmWavcErzp1VFvX6ZrIaKJ__NdkM7giP6-15AF8.png 08-Sep-20 02:21 PM that looks like one (1) money 08-Sep-20 02:21 PM my MCP has this nifty extended 2.75" CF port for the four SHV connectors used to power the thing, and if i could move those somewhere i could drop a viewport/screen in place and slap a camera on or somesuch 08-Sep-20 02:21 PM really gotta build some kinda clean assembly space for it, kinda afraid to take the plastic cover off it until i can guarantee it won't get (more) dust on it 08-Sep-20 02:21 PM no guarantee it even works anyways 08-Sep-20 02:35 PM I've been told the filthy room my laser is in 08-Sep-20 02:35 PM is cleaner than a lot of "clean rooms" universities let students use 08-Sep-20 02:35 PM and uh, you wanna be keeping you mcp in vacuum... 08-Sep-20 02:44 PM yeahwell 08-Sep-20 02:44 PM it sat on a shelf for a couple months 08-Sep-20 02:45 PM when you turn it on, go slow 08-Sep-20 02:45 PM we'll see how bad it is once i do, yeah 08-Sep-20 02:45 PM I'm gonna leave it at 10-7 for a week first probably 08-Sep-20 02:45 PM that is a good idea 08-Sep-20 02:45 PM and then ramp it up reeeeeal slow 08-Sep-20 02:46 PM here's the "real" procedure 08-Sep-20 02:46 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Tectra_MCP_instructions-EDD53.pdf 08-Sep-20 02:48 PM ah, i like that little spark protector circuit 08-Sep-20 02:48 PM there's one to throw in a pomona box and leave stuck to my picoammeter 08-Sep-20 02:49 PM we just have 1Mohm power resistors all over the place for high voltage stuff 08-Sep-20 02:49 PM thou shalt not draw current 08-Sep-20 02:49 PM yep same 08-Sep-20 02:49 PM 1, 5, 10m, bunch of 400M resistors i've been meaning to measure 08-Sep-20 02:49 PM i think one of my ion chambers has a teraohm hiding in it 08-Sep-20 02:51 PM oh they might be 100M 08-Sep-20 02:51 PM IDR 08-Sep-20 02:53 PM 100M sounds a little more right 08-Sep-20 02:53 PM 50μA at 5kV should be enough for anyone 08-Sep-20 02:54 PM 20kV soooon 08-Sep-20 02:54 PM It's just for ion lensing, so really the current should be... Nothing... 08-Sep-20 02:55 PM ooh fun 08-Sep-20 02:55 PM i can't wait to be offboarded from my crap job so i can divert all my do-stuff energy back into project work 08-Sep-20 02:55 PM have a couple months of funemployment before the panic sets in 08-Sep-20 02:55 PM are MCPs without a photocathode solarblind, or do i need to light-seal everything to use one? 08-Sep-20 03:00 PM Should be fine without sealing 08-Sep-20 03:00 PM I know several people who have the same phosphor types as us (from various brands) and when measuring ToF by MCP current they have no light shielding 08-Sep-20 03:01 PM huh, wow 08-Sep-20 03:01 PM also nice, I'll be able to keep my ion gauges running 08-Sep-20 03:01 PM (they're very bright apparently) 08-Sep-20 03:01 PM they 08-Sep-20 03:01 PM produce ions 08-Sep-20 03:01 PM ions excite the MCP 08-Sep-20 03:02 PM so, like, keep it off-axis? 08-Sep-20 03:04 PM an ion gauge in the red pen spot would make ions visible on an unshielded MCP in the blue pen spot 08-Sep-20 03:04 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DC1CE.png 08-Sep-20 03:04 PM an RGA on the flange to the right of the red pen will also send ions flying 08-Sep-20 03:05 PM hrm 08-Sep-20 03:06 PM we have these now which we can keep on: https://www.mksinst.com/f/500-cold-cathode-gauge-module 08-Sep-20 03:07 PM oh nice 08-Sep-20 03:07 PM i've also never had my UHV side put together without having at least one KF16 o-ring (my ion gauges are all KF) so like. maybe i oughta find another gauge in general 08-Sep-20 03:07 PM RGA is kind of a 'run as i need it' kinda thing at least, mostly got mine for leak checking 08-Sep-20 03:09 PM Are you going to make a ToF mass spec with the MCP? 08-Sep-20 03:10 PM not sure honestly 08-Sep-20 03:10 PM it's a resistive anode encoder MCP 08-Sep-20 03:10 PM which i.. don't think is what's usually used for fast response 08-Sep-20 03:10 PM 2d imaging otoh 08-Sep-20 03:10 PM could be wrong, i have basically 0 experience with these things 08-Sep-20 03:10 PM it's a neat little chevron mcp with an extra isolated/feedthrough'd ring in front for, idk, mounting and biasing a photocathode or smth on 08-Sep-20 03:13 PM extra as in three total? 08-Sep-20 03:13 PM three feedthroughs? 08-Sep-20 03:13 PM Yeah 08-Sep-20 03:14 PM it has 4 SHV for HV + signal, and then like six 1.33” BNCs (one general anode signal, i think? that is a floating-ground bnc) 08-Sep-20 03:14 PM Ah, loads 08-Sep-20 03:15 PM yeah three rings total though 08-Sep-20 03:15 PM i also managed to find the X-Y position analyzer for it, which honestly i should just rack & hook up & gently poke at 08-Sep-20 03:17 PM Why 4 SHV? 08-Sep-20 03:17 PM i am only really missing amplifiers to make it run, and thankfully i have.. a couple 08-Sep-20 03:17 PM the six BNC are for position information from an anode array aren't they? 08-Sep-20 04:57 PM whoops got lost in mendeley 08-Sep-20 04:57 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_2020-09-08-16-55-04-60B9B.png 08-Sep-20 04:57 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_2020-09-08-16-55-44-60967.png 08-Sep-20 04:57 PM but, yes 08-Sep-20 04:57 PM guess the SHV are just for biasing 08-Sep-20 05:01 PM Wait, you get to bias each of your MCPs independently?? 08-Sep-20 05:01 PM I've always seen them chained, so just front and back 08-Sep-20 05:01 PM Anyways cool. You could do what I do with that 08-Sep-20 05:04 PM you do helium microdroplet stuff, right? 08-Sep-20 05:06 PM I don't think they ever get beyond nanosize but yes 08-Sep-20 05:06 PM oh fair 08-Sep-20 05:06 PM but specifically, this is what you can do: 08-Sep-20 05:06 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Schematic-of-multi-coincidence-velocity-ma-F82E6.png 08-Sep-20 05:06 PM it's just that when I do it it looks like this: 08-Sep-20 05:06 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Schematic-representation-of-the-experiment-DE1E6.png 08-Sep-20 05:10 PM OH 08-Sep-20 05:10 PM i see what you're doing 08-Sep-20 05:10 PM that's cool :o 08-Sep-20 05:10 PM .. i think? what's the (pinhole?) at -2kV made of? 08-Sep-20 05:12 PM stainless steel 08-Sep-20 05:13 PM oh okay so it's just for the gradient 08-Sep-20 05:13 PM what is cΤ exactly? 08-Sep-20 05:13 PM like is there a resonance between those two transitions or smth 08-Sep-20 05:14 PM cT? 08-Sep-20 05:16 PM cτ 08-Sep-20 05:16 PM oh that's just a delay 08-Sep-20 05:16 PM don't know why they'd give it in units of distance 08-Sep-20 05:16 PM here's my figure of the same thing, with the camera/phosphor replaced with the actual image 08-Sep-20 05:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-29C36.png 08-Sep-20 05:16 PM in both cases the flight path isn't shown, there's like 40cm between the lower voltage plate and the MCP 08-Sep-20 05:16 PM here's what the CAD file of the current one looks like: 08-Sep-20 05:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F9F29.png 08-Sep-20 05:22 PM oh in the paper it says the repeller has a 1" and also a 3mm hole 08-Sep-20 05:22 PM typo? 08-Sep-20 05:23 PM yeah lol 08-Sep-20 05:23 PM the second plate is called extractor 08-Sep-20 05:23 PM thanks 08-Sep-20 05:24 PM ah ok that makes sense 08-Sep-20 05:25 PM But yeah with your MCP and anode thing, you get spatial information... So you can make a Velocity Map Imaging Time of Flight spectrometer like this really easily, and shoot electrons at molecules to break them apart and see their coulomb energy! 08-Sep-20 05:26 PM i had considered using my MCP as the sensor beneath a small ion trap to attempt single ion imaging of cold lattices 08-Sep-20 05:26 PM turn off the trap and let gravity smear out their velocities and use that to measure temperature idk 08-Sep-20 05:26 PM its a ways away 08-Sep-20 05:26 PM If i figure out how to make good lenses I had also considered stealing some ideas from the accelerator kicker design ppl and trying to design a streak camera 08-Sep-20 05:29 PM ions need quite a bit of energy to be amplified well by the MCP 08-Sep-20 05:31 PM hmm 08-Sep-20 05:33 PM Like really, the detection efficiency is terrible 09-Sep-20 06:07 AM https://twitter.com/GigaBecquerel/status/1303679989305487362?s=19 09-Sep-20 10:31 AM And we're still cleaning up from it. 09-Sep-20 11:12 AM you can come visit me once I'm done with it 09-Sep-20 11:12 AM :P 09-Sep-20 11:12 AM luckily I don't have access to a few MBq of P32 09-Sep-20 11:12 AM 'tho the uranium (decay chain) chemistry is questionable 09-Sep-20 11:57 AM i don't have any nitric acid, but is that still the right way to gather an atmospheric sample? 09-Sep-20 11:57 AM asking for a wildfi... friend 09-Sep-20 11:58 AM a wild friend? 09-Sep-20 11:58 AM tbh I was a bit surprised that they don't suck any air through it 09-Sep-20 11:58 AM that's how I know it 09-Sep-20 11:59 AM My Combustible Chums gestures at the redwoods 09-Sep-20 11:59 AM filter paper and a whole lot of air 09-Sep-20 11:59 AM yeah same here 09-Sep-20 11:59 AM https://assets.thermofisher.com/TFS-Assets/MBD/product-images/Oxoid-Air-Sampler.jpg-650.jpg heh this looks like a detector on its own 09-Sep-20 11:59 AM side channel blower and ho for it 09-Sep-20 11:59 AM oh or maybe a fan blowing at some paper 09-Sep-20 12:01 PM so once you have a grimy paper/filter, is burning/ashing necessary? 09-Sep-20 12:01 PM way less efficiency but still 09-Sep-20 12:02 PM it is like, on-and-off snowing ash here 09-Sep-20 12:02 PM cars are salt & peppered 09-Sep-20 12:02 PM in that case just wipe a car down with a wet rag 09-Sep-20 12:02 PM no ashing needed, as paper provides basically no self-shielding 09-Sep-20 12:03 PM i grabbed some 2” masking tape squares of ash but it doesn't seem to register above background 09-Sep-20 12:03 PM you'll need more, and an over night measurement in lead 09-Sep-20 12:03 PM you should at least get a strong ⁴⁰K line 09-Sep-20 12:10 PM Now, now @qualia. Do not malign our almost asbestos trees, the mighty sequoia sempervirens. That’s Douglas fir and oak coating your laser optics and filling you air filters. 09-Sep-20 12:12 PM wait 09-Sep-20 12:12 PM is there actually a strong correlation between forest fires 09-Sep-20 12:12 PM and laser labs being mad about their optics getting ruined? 09-Sep-20 12:20 PM i definitely sealed up my nice HeNe with a glove and a hairband and am not letting it out until the air isn't quite so chunky 09-Sep-20 12:20 PM good thing you're already wearing masks 09-Sep-20 12:22 PM good thing our house is all weirdos and we all have identical military full-face gasmasks 09-Sep-20 12:23 PM I was expecting masks more relevant to your display photo 09-Sep-20 12:24 PM nice 09-Sep-20 12:24 PM the right kind of weirdos, evidentaly 09-Sep-20 12:25 PM look i have already put far too much thought into designing a half-life-HEV-suit-style cyborg ppe fursuit 09-Sep-20 12:27 PM https://pbs.twimg.com/media/DgL_jpPVQAAf_v-.jpg 09-Sep-20 12:27 PM or something along those lines 09-Sep-20 12:28 PM ssssure 09-Sep-20 12:50 PM Labs that didn't already have local HEPA laminar flow hoods have been advised to cover their benches. Like, more than normal compared to the dust the house air normally spews. 09-Sep-20 12:50 PM can you really call yourself a laser lab if you don't have HEPA hoods? 09-Sep-20 12:50 PM I don't know any here that don't have that + also an acrylic or similar cover built all aroudn the table. us and our neighbours also have a layer of curtains too 09-Sep-20 12:50 PM and in general we're bad 09-Sep-20 01:51 PM i taped a MERV 7 filter to a box fan does that count 12-Sep-20 04:34 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200912_132638-9B164.jpg 12-Sep-20 04:34 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200912_132905-A7BDB.jpg 12-Sep-20 04:34 AM whoops 12-Sep-20 06:02 AM also the red pitaya works well as MCA, those are 1 µs pulses from my function generator 12-Sep-20 06:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-9F739.png 12-Sep-20 06:52 AM noice 12-Sep-20 06:53 AM pretty damn noice 12-Sep-20 06:53 AM 'cause even at new price it still costs way less than any "off the shelf MCA" 12-Sep-20 09:52 AM hmm 12-Sep-20 09:52 AM I mean, I'm also usibg red pitaya for some optics stuff 12-Sep-20 09:52 AM the "sh.t" message was rejected ️ 12-Sep-20 09:52 AM (used sht instead of stuff) 12-Sep-20 09:52 AM currently tryin to build a faster DAQ 12-Sep-20 09:52 AM (got stuck on the schematics) 12-Sep-20 10:20 AM what red pitaya board are you guys using as an MCA? was looking at those awhile back but never ended up buying one and just stuck with my sound card 12-Sep-20 10:20 AM one of those would be way better 12-Sep-20 10:25 AM 125-14 I think 12-Sep-20 10:25 AM it's actually hard to find out what model you have 12-Sep-20 10:25 AM also the software is meh, just 1k or 16 k channels, nothing inbetween 12-Sep-20 10:25 AM but it works so much better than soundcard, simply because it can sample more and faster Pulses 12-Sep-20 10:25 AM That's the output of my labr spectrometer, with 500 ns pulses 12-Sep-20 10:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200912_192632_714-1F5A3.jpg 12-Sep-20 12:58 PM yum yum radium 12-Sep-20 01:00 PM teehee 12-Sep-20 01:00 PM the only thing that that sucks a bit is that the red pitaya has 0-1V or 0-20V input 12-Sep-20 01:00 PM and nim is 0-10V 12-Sep-20 01:00 PM also the software is kinda eh, no energy calibration etc 12-Sep-20 01:00 PM but it outputs csv, so you can just make some macro for that 12-Sep-20 01:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200912_132216-9286D.jpg 12-Sep-20 01:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200912_132201-FD445.jpg 12-Sep-20 01:22 PM oh, and, after 24h of counting.. nothing particularly exciting stands out from my vile wildfire ash sample 12-Sep-20 01:22 PM except whatever that hump is, which may just be some kind of clipping pileup 12-Sep-20 01:24 PM looks like it 12-Sep-20 01:24 PM what's the peak on the left? 12-Sep-20 01:25 PM just lead x-rays 12-Sep-20 01:25 PM ah, right 12-Sep-20 01:25 PM interesting just how empty it is 12-Sep-20 01:25 PM oh 12-Sep-20 01:25 PM duh 12-Sep-20 01:25 PM the peak is potassium 12-Sep-20 01:25 PM ash is always full of potassium 12-Sep-20 01:25 PM pot ash, guess what it was discovered in 12-Sep-20 01:26 PM hmm! 12-Sep-20 01:26 PM i know one way to confirm that...! 12-Sep-20 01:26 PM (fwiw, channel should be roughly keV also) 12-Sep-20 01:27 PM so not too far off 12-Sep-20 01:27 PM 1380 vs 1460 12-Sep-20 01:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200912_133304-97F9F.jpg 12-Sep-20 01:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20200912_133404-70CD2.jpg 12-Sep-20 01:35 PM now we wait 12-Sep-20 01:37 PM ah 12-Sep-20 01:37 PM low-activity sample measurement is great because i'm technically being productive while loafing around for days at a time 12-Sep-20 01:38 PM XD 12-Sep-20 01:38 PM until you forget to refill the ln2 12-Sep-20 01:40 PM i don't think i could realistically be trusted with a cryocooled detector without some kind of extremely obnoxious low-ln2 alarming system tbh 12-Sep-20 01:40 PM way too scatterbrained for 'remembering things' 12-Sep-20 01:42 PM I also let mine warm up a few times 12-Sep-20 01:42 PM good thing I have an interlock that turns off bias 12-Sep-20 01:46 PM Just get a cold head 12-Sep-20 01:46 PM oh I'd love to 12-Sep-20 01:47 PM Id love two, need a cryopump 12-Sep-20 01:47 PM TOO MUCH N2 IN MY CHAMBER 12-Sep-20 01:47 PM I have coldhead and am getting compressor and hoses 12-Sep-20 01:47 PM but I am not sure if I want to trickle-charge my ln2 dewar with 2 kW 12-Sep-20 01:50 PM Just move somewhere you can build your own power plant 12-Sep-20 01:50 PM How much does a home geothermal plant generate? 12-Sep-20 01:52 PM good question 12-Sep-20 01:52 PM no idea 12-Sep-20 05:44 PM How much vibration is caused by Coldheads? I've not seen one working but would assume they vibrate lots, which'd be crap for sensitive stuff. 12-Sep-20 05:53 PM It depends. These exist: https://www.arscryo.com/ultra-low-vibration-ulv But then pulse tubes don’t even have mechanical movement. 12-Sep-20 06:13 PM interesting 13-Sep-20 12:27 AM my gm cryocooler visibly rocks back and forth, as it moves its ~1 kg regenerator 13-Sep-20 12:27 AM https://www.youtube.com/watch?v=RYQ6ZKh6JDg 13-Sep-20 01:28 PM omg it's soooo cyoooooooote 13-Sep-20 01:28 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1C57C.png 13-Sep-20 01:47 PM Has anyone here got information on old Canberra Detectors? I am looking for info on a 715005E and the 7600P cryostat. 13-Sep-20 02:23 PM my gm cryocooler visibly rocks back and forth, as it moves its ~1 kg regenerator @GigaSquirrel wow that is really slow, my STI cryo cooler runs at 60hz 13-Sep-20 02:23 PM it's GM, not PTR 13-Sep-20 02:23 PM has to move a two stage regenerator, full of lead and copper 14-Sep-20 11:47 AM @funranium your twitter thread about tritium lab work just popped into my mind during a biochem lecture. Paper we were discussing used tritiated sucrose for determining lipid exchange between vesicles 14-Sep-20 12:10 PM Hooray! I’m helping with learning. Thank you. The CHOOSE YOUR RADIATION ADVENTURE threads are mainly to help people work out some reasoning for “What is most appropriate/effective or least bad in a situation?” Sometimes it leads to me having to ask new questions such as what is the current state of the Tajoura Nuclear Centre. 15-Sep-20 02:37 AM sounds rad 15-Sep-20 11:26 AM Yeah, they’re really interesting and all so far out my frame of reference from my normal radiation safety stuff. Makes me kinda start questioning whether to look at studying health physics as opposed to chemistry for grad school 15-Sep-20 01:05 PM Do not use my career as a metric for the average health physicist. I am, and always have been, a weird magnet. I should also say no to more things than I do, but yes leads to ADVENTURE!!! 15-Sep-20 01:07 PM Does health physicist mean you can get your hands on a pretty blue glowing vial of actinium? >_> 15-Sep-20 01:13 PM you can, but as a health physicist you know better 15-Sep-20 02:01 PM Never encountered isolated actinium in quantities sufficient to need a vial. Curium, on the other hand... The swearing filter won’t let me express my full feelings about curium here. 15-Sep-20 02:02 PM Is there a way to wind up being a magnet for weird? 15-Sep-20 02:02 PM Because it ends up feeling sorta similar to another interest in being an instrumentation chemist. Sorry, kinda just rambling 15-Sep-20 02:50 PM I find weird accumulates. 15-Sep-20 02:52 PM the missus and i are accomplished sh*tmagnets and our strategy has also involved a lot of saying yes to and subsequently following through with all kinds of bad ideas 15-Sep-20 02:52 PM align yrself towards an openness to new experiences and it tends to find you nodnod 15-Sep-20 02:55 PM well that seems straight forward enough, I think I've run into that a couple of times already honestly 15-Sep-20 04:32 PM And then, eventually, you're that person everyone brings cursed boxes they find in the attic or basement to. Just in case they're radioactive and they should live in your house instead. 15-Sep-20 09:42 PM I cannot confirm nor deny this phenomenon. So unrelated, who has some cheap lead sheet I can buy? 15-Sep-20 09:42 PM Hahaha 15-Sep-20 10:05 PM Those four rolls are mine and you can't have them. 15-Sep-20 10:48 PM lead sheet can be had for cheap at roof supply stores ...unless fun is known to cause cancer in your state 15-Sep-20 10:49 PM ... depending on where you live 15-Sep-20 10:49 PM hardware store people in CA will look at you like you have three heads if you go asking around for lead flashing 15-Sep-20 10:49 PM maybe it's easier elsewhere 15-Sep-20 10:49 PM heh 15-Sep-20 10:51 PM I had to label our pile of lead 15-Sep-20 10:52 PM we have to dispose of lead properly, and lead solder has been banned, but for roofing you can still get it 15-Sep-20 10:52 PM actually paid like 150% of the lead price at our scrapyard, so still fairly cheap imo 15-Sep-20 10:54 PM I don’t think you can effectively ban some stuff from the depths of poorly patrolled departments 15-Sep-20 10:55 PM well, they've banned selling it 15-Sep-20 10:56 PM We already hoard stuff that’s easily attainable 16-Sep-20 07:31 AM @GigaSquirrel I live in California. Our air has a prop 65 cancer warning on it. 16-Sep-20 07:31 AM Actually about lead..... you can still buy and use it in California. It just can’t be thrown away and must be recycled properly. Roofing lead however has been banned for decades for earthquake reasons. 16-Sep-20 07:37 AM @GigaSquirrel I live in California. Our air has a prop 65 cancer warning on it. @Charles 16-Sep-20 07:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unnamed-E09DF.jpg 16-Sep-20 07:39 AM still allegedly 150+ here 16-Sep-20 09:01 AM 150+ what? 16-Sep-20 09:07 AM Air quality index 16-Sep-20 09:07 AM Or whatever. Units don’t bother me here 16-Sep-20 09:08 AM It was over 500 here for a bit. I just wore my paint respirator 16-Sep-20 09:09 AM Sunday was awful here 16-Sep-20 09:09 AM But it has been raining 18-Sep-20 01:10 AM InterSpec! 18-Sep-20 01:10 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/file-C855A.png 18-Sep-20 01:14 AM NaI? Or some other detector? 18-Sep-20 01:14 AM LaBr 18-Sep-20 01:15 AM Ah, didn't want to fill your HPGe all the time with LN2? 18-Sep-20 01:15 AM With a sexy 3.13% FWHM at that 609 keV peak 18-Sep-20 01:15 AM Aye 18-Sep-20 01:16 AM It's pretty nice, how's detector efficiency compare with other crystals? I've yet to see inorganics beat BGO 18-Sep-20 01:16 AM Well density isn't as high of course 18-Sep-20 01:16 AM also my crystal is tiny 18-Sep-20 01:16 AM 10x20 mm 18-Sep-20 01:17 AM Ah speaking of detectors, this thing: https://www.ebay.com/itm/Canberra-Industries-model-2001-Liquid-Nitrogen-dewar-tanl-vessel-and-more/283512272837 18-Sep-20 01:17 AM Is it HPGe? I don't think Canberra make a lot of Ge(Li) or Si(Li) detectors in this cryostat packaging 18-Sep-20 01:18 AM I have absolutely no idea 18-Sep-20 01:18 AM No detector model number, the preamp is apparently used in some old HPGe from the 80s 18-Sep-20 01:18 AM http://canberra-industries-50years.com/index.html You can ask this guy, he really knows his old detectors 18-Sep-20 01:19 AM And the dent is a bit concerning, hopefully it's just damaged the outer layer of the vacuum vessel 18-Sep-20 01:19 AM yep... 18-Sep-20 01:25 AM Did you collect that LaBr spectrum with the red pitaya? 18-Sep-20 01:25 AM Aye 18-Sep-20 01:26 AM Hmm, I should get one... 18-Sep-20 01:26 AM teehee 18-Sep-20 01:26 AM they can be had used for fairly cheap from what I've seen 18-Sep-20 03:00 AM friends ❤️ 18-Sep-20 03:00 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3D8EB.png 18-Sep-20 03:44 AM also damn interspec is surprisingly intuitive 18-Sep-20 03:44 AM finally some good piece of software 18-Sep-20 06:16 AM I need to get it and learn it. 18-Sep-20 06:22 AM I also need to get friends 18-Sep-20 08:16 AM oh man the nuclide ID works sooo well 18-Sep-20 09:05 AM @GigaSquirrel Did you figure out which red pitaya model you have? Think before you said you thought you had the 125-14 but then I also think I saw you asking if anyone had one for sale... 18-Sep-20 09:21 AM Yep, I've got the 125-14! 18-Sep-20 09:35 AM Nice seems like they are not crazy expensive even to buy those new but still enough that I need to decide if I really want to grab one... Mouser has them for $310 https://www.mouser.com/ProductDetail/Red-Pitaya/28?qs=iS7aw2r6gpnjFgznl4%252BAvA%3D%3D which is a lot nicer a price than buying directly from the red pitaya website (275,00€+60,50€+shipping). 18-Sep-20 09:36 AM The 125-10 only has a 10 bit ADC, and the software documentation said it will have issues with that 18-Sep-20 09:36 AM also 10 bit are a bit meh for spectroscopy 18-Sep-20 09:36 AM and the sdr lab stuff isn't good for spec 18-Sep-20 09:36 AM also you techincally get two MCAs per pitaya 18-Sep-20 09:38 AM does the code written for the MCA functionality work to do collection on both inputs at one time? 18-Sep-20 09:38 AM would assume not but that would be really neat if you can run them side by side on the one board 18-Sep-20 09:42 AM yeah you can use them both independantly 18-Sep-20 10:02 AM Yeah I was super impressed by InterSpec when I first found it too. It used to crash a lot, but most of the issues are now gone. Try the mobile app! 18-Sep-20 10:03 AM Same here, it’s my go to for working with stuff away from the counting room computers 18-Sep-20 10:04 AM An astounding... 100+ downloads on google play 18-Sep-20 10:04 AM my phone feels a bit too small for that but in general the app works really well 18-Sep-20 10:04 AM at this point it might make sense to invest in a tablet 19-Sep-20 02:07 AM so, what exactly is the legal situation on trinitite? 19-Sep-20 02:07 AM I remember that it's illegal to collect new stuff, but what about stuff sold online? 19-Sep-20 02:07 AM and what about crossing borders? 19-Sep-20 02:07 AM Maybe @funranium can say something about that? 19-Sep-20 09:40 AM Pretty sure it is all legal to trade in and ship internationally as long as you do not collect new stuff 19-Sep-20 09:43 AM hmm ok 19-Sep-20 09:43 AM but someone from germany offered me a sample, so that's a non issue now 19-Sep-20 09:58 AM Lucky for you and a generous offer. I had to buy all the trinitite I have 19-Sep-20 09:59 AM Yep, I'm really glad about that! 19-Sep-20 09:59 AM I am slowly working up to more interesting samples for spectroscopy, not just U / Ra / Th and the likes 19-Sep-20 09:59 AM My chernobyl berries and fookooshima soil are a good start 19-Sep-20 10:01 AM if I had access to an HPGe I would probably have the same sort of issue with collecting stuff like that haha 19-Sep-20 10:01 AM Would be cool to compare the spectra from a "normal" piece to the piece of trinitite w/ a chunk of gravel in it that I have but my NaI(Tl) does not have nearly enough resolution for that 19-Sep-20 10:03 AM Esp now that I got my low energy Ge, great for transuranics 19-Sep-20 10:03 AM Not sure what you mean, compare trinitite with gravel? 19-Sep-20 10:09 AM Sort of. Compare "normal" trinitite to a piece of trinitite surrounding a chunk of gravel 19-Sep-20 10:09 AM I've been told it probably was gravel that made up the pad at ground zero 19-Sep-20 10:09 AM Not sure I really believe that 19-Sep-20 10:10 AM what's normal trinite? 19-Sep-20 10:10 AM it's all manmade in the Explosion 19-Sep-20 10:11 AM Yeah I just mean normal as in green tinted w/ bubbles 19-Sep-20 10:11 AM Not the red or black 19-Sep-20 10:11 AM before that it was whatevet makes up the sandy whites(?) flat 19-Sep-20 10:12 AM The area is not really sandy...mostly just desert dirt 19-Sep-20 10:12 AM Could have been different before the test as there has been a lot of remediation though 19-Sep-20 10:23 AM but the test site is called White sands range ^^ 19-Sep-20 10:25 AM The white sandy areas are, if I remember right, Southwest from the area the test happened 19-Sep-20 10:25 AM Been to White Sands a couple times but only to Trinity once 19-Sep-20 10:25 AM that's what I meant 19-Sep-20 10:25 AM no idea what it's actually made up of 19-Sep-20 10:26 AM the White Sands national park area is stunningly beautiful 19-Sep-20 10:26 AM Trinity site is mostly just a big fenced in area of desert inside the missile range 19-Sep-20 10:26 AM Still very cool to visit 19-Sep-20 10:26 AM The missile museum is worth a stop too if you are in that area of NM 19-Sep-20 10:28 AM @GigaSquirrel What samples do you use to do energy calibration of your HPGe detector? 19-Sep-20 10:31 AM http://www.minresco.com/trinitite/bk5154%20trinitite%20book.htm 19-Sep-20 10:31 AM That book is amazing BTW 19-Sep-20 10:31 AM Goes into great detail about the test, formation, composition, varieties, etc about trinitite 19-Sep-20 10:32 AM Best thing about trinity is Taylor’s math 19-Sep-20 10:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200919_102230-84CE3.jpg 19-Sep-20 10:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200919_102142-84980.jpg 19-Sep-20 10:37 AM I spent way too much on those pieces haha but the bottom one was too cool to pass up and they gave me a break on the other pieces. 19-Sep-20 10:37 AM On the right side you can see a sort of greyish blob surrounded by green. That is the piece of rock/gravel. 19-Sep-20 10:50 AM @GigaSquirrel What samples do you use to do energy calibration of your HPGe detector? @Mason_Yu usually radium 19-Sep-20 10:50 AM for lower energy stuff Th / Am 19-Sep-20 10:50 AM I'd love to visit the Trinity site and los alamos one day 19-Sep-20 10:56 AM planning for Trinity is frustrating with how narrow the windows to visit are 19-Sep-20 10:56 AM Yeah some of my friends got some trinitite a few years ago, hard to find larger samples now though. 19-Sep-20 10:57 AM I wonder if they are doing the Trinity opening this year at all 19-Sep-20 10:57 AM I know the one earlier in the year got cancelled 19-Sep-20 10:57 AM https://www.wsmr.army.mil/Trinity/Pages/Home.aspx 19-Sep-20 10:57 AM ...nope 19-Sep-20 10:57 AM Also for future years just to give you warning... Get in line (in your car) well before they open the gate onto the base. 19-Sep-20 10:57 AM I was almost an hour before they opened the gates and still almost 0.75mi back 19-Sep-20 10:57 AM Line went all the way out to the main road 19-Sep-20 11:00 AM do they only let a few people in there at a time? 19-Sep-20 11:01 AM No but unless you want to hike a decent amount to get to the outside gate of the Trinity site you probably want to be there early 19-Sep-20 11:01 AM The parking lot might also fill up...not really sure on that but it was pretty full when I was leaving 19-Sep-20 11:01 AM https://www.google.com/maps/place/Trinity+Site/@33.6749626,-106.4773149,959m/data=!3m2!1e3!4b1 19-Sep-20 11:01 AM You park in the big grey gravel area and then have to walk into the actual site 19-Sep-20 11:10 AM I was debating if I should get a set of button check sources or not. http://unitednuclear.com/index.php?main_page=product_info&cPath=2_5&products_id=474&zenid=qiakoahb195iorj72varn7hdj7 19-Sep-20 11:10 AM Surprisingly quite affordable 19-Sep-20 11:10 AM I'd definitely get them 19-Sep-20 11:10 AM for efficiency calibration 19-Sep-20 11:10 AM Would make calibration easy and enable efficiency calibration too yeah 19-Sep-20 11:12 AM I wish I could get them here 19-Sep-20 11:12 AM they're all above the legal limit (10 kBq for most) 19-Sep-20 11:12 AM also for hpge spec I'd go with ~100 Bq 19-Sep-20 11:12 AM it really shines at low rates 19-Sep-20 11:12 AM even with my "just" 20% I get summing continua (peak trailing to the left) with ~1 kBq Ra 19-Sep-20 11:15 AM Wow, do you have a planar detector? How thick is the crystal? 19-Sep-20 11:15 AM And you've got two now? 19-Sep-20 11:16 AM 20% coaxial 19-Sep-20 11:16 AM now I also have a 500 mm² 5 mm thick planar one, but that still needs refurb 19-Sep-20 11:17 AM I'm so jealous... There is a HPGe at work that is having some issues at the moment, I have my eyes set on it 19-Sep-20 11:17 AM It's efficiency has continuously decreased over the past few years 19-Sep-20 11:17 AM Always been kept cold 19-Sep-20 11:18 AM yeah I got really lucky with those two 19-Sep-20 11:18 AM the planar one has bad vacuum and a dead frontend fet, not sure if I can reanimate this one 19-Sep-20 11:18 AM Got really bad in the past few months, perhaps it was a vacuum problem? But yeah I don't think they're planning to get rid of it anytime soon 19-Sep-20 11:19 AM bad resolutionwhise? 19-Sep-20 11:19 AM No problems on that front 19-Sep-20 11:19 AM As far as I know... But the main use is for counting activation foils to compute thermal neutron fluxes, so efficiency calibration is critical 19-Sep-20 11:20 AM and... the efficiency is gettong worse? O.o 19-Sep-20 11:20 AM vacuum issues cause it to get warmer => worse resolution, until something arcs over and the fet dies 19-Sep-20 11:24 AM I don't think it was a vacuum issue then... Not sure about the details on how much the efficiency has decreased. But it looks like people are still using it to count other samples and the resolution seems more than acceptable 19-Sep-20 11:24 AM https://www.pasco.com/products/lab-apparatus/atomic-and-nuclear/sn-7949#specs-panel 19-Sep-20 11:24 AM For people who are still in school, a heavy discount is available 19-Sep-20 11:24 AM The activity uncertainty on these button sources makes efficiency calibration tricky 19-Sep-20 11:26 AM to be honest I am not sure how the efficiency can change 19-Sep-20 11:26 AM if the intrinsic region got smaller eg. less depletion that might do it, but that would be strongly visible by a cut off lower energy end 19-Sep-20 11:28 AM Well I'd think a decrease in bias voltage would be really easily noticeable 19-Sep-20 11:29 AM yep 19-Sep-20 11:29 AM They must have adjusted the bias voltage too when troubleshooting this 19-Sep-20 11:29 AM weird either way 19-Sep-20 11:30 AM Or it might be some problems with pulse shaping and amplifiers down the chain 19-Sep-20 11:30 AM keep me updated if you guys ever found the solution ^^ 19-Sep-20 11:31 AM I'm hoping an easy solution is not found to be honest 19-Sep-20 11:31 AM Then they'll get another detector and relegate this one to an eager employee 19-Sep-20 11:32 AM hehe 19-Sep-20 11:32 AM good luck! 19-Sep-20 01:31 PM If anybody has an Amptek dp5 mca, I finally got the python software unf_cked for it 19-Sep-20 01:42 PM @GigaSquirrel Just asked the guy who is working on the HPGe, it was apparently a combination of a few problems. It lost LN2 a couple of months ago and although the LN2 monitor automatically cut the bias, the efficiency problems started from there, they had to use higher and higher bias voltages starting from then. They are also now suspecting there is a vacuum problem and is waiting for a fitting from Lesker to pump it down again 19-Sep-20 01:42 PM Also the detector was an eBay find lol 19-Sep-20 01:46 PM Ouh 19-Sep-20 01:46 PM that doesn't sound good 19-Sep-20 01:46 PM Sounds like it's about to be dead for good 19-Sep-20 01:47 PM the crystal definitely has suffered 19-Sep-20 01:47 PM Hey I'll still take it 19-Sep-20 01:47 PM Would make a nice paperweight 19-Sep-20 01:48 PM I was debating if I should get a set of button check sources or not. @Mason_Yu Our go to is eu-152 19-Sep-20 01:49 PM For energy or efficiency calibration? 19-Sep-20 01:49 PM It’s good except for the <200 kev range 19-Sep-20 01:49 PM Both 19-Sep-20 01:51 PM yeah a "bad" hpge is still worlds better than most else 19-Sep-20 01:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-AF341.png 19-Sep-20 01:52 PM Hmm, $50$100, might just get it https://www.a3bs.com/eu-152-radioactive-source-u41532-spectrum-techniques-eu-152,p_666_1742.html 19-Sep-20 01:52 PM $50? 19-Sep-20 01:53 PM issue with the button check yources for effcal is that your sample to be measured has to be in the same geometry 19-Sep-20 01:53 PM Whoops wrong link, I saw they had $400 for the RSS-8 source set, so $50 per source for most of the stuff on that site except Eu-152 19-Sep-20 01:53 PM https://www.a3bs.com/set-of-8-sources-u41513-spectrum-techniques-rss8,p_666_1730.html 19-Sep-20 01:53 PM Yeah, almost every sample we work with is in a vial so we have a custom liquid in vial source 19-Sep-20 01:54 PM That's the case for almost all sources though... I'm not too worried about efficiency calibration personally so it's not a problem 19-Sep-20 01:54 PM well then no worries ^^ 19-Sep-20 01:54 PM but if you only want ecal you can use Radium 19-Sep-20 01:54 PM I usually use an old compass 19-Sep-20 01:58 PM If you were planning on the RSS-8 set, I wonder how much a single calibrated source would cost 19-Sep-20 01:58 PM As far as I know all the sources by Spectrum Techniques have 15% activity uncertainty? 19-Sep-20 01:59 PM that's the quote I got from spectrum 19-Sep-20 01:59 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-06D00.png 19-Sep-20 02:00 PM Ah, actually 20% without calibration 19-Sep-20 02:00 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-AAA12.png 19-Sep-20 02:00 PM But, I may have access to the calibrated detector at work, so no worries! Saves $150 19-Sep-20 02:01 PM yeah, remind me to do that same thing before I leave Reed... 19-Sep-20 02:02 PM You are correct @LRM. Trade of trinitite currently in circulation is allowed and more or less impossible to stop. The collection of new samples is expressly forbidden and they bulldozed most of the site to help prevent that several decades ago. You can still find some small bits around, but you’re not supposed to take them. Much like you aren’t supposed to collect anything in National Park without a permit. 19-Sep-20 02:04 PM I think Trinity Site is technically covered under the same banner as National Monuments instead of National Parks but the difference is almost entirely pedantic 19-Sep-20 02:04 PM Any idea what sort of trouble you get into if you walk through the open gate in the outer fenced area of the site? It was so tempting but I did not feel like getting into trouble on a military base was a good idea 19-Sep-20 02:09 PM good to know, thanks @funranium 19-Sep-20 02:12 PM Trespassing, but under MCJ. Their response time can be surprisingly fast. 19-Sep-20 02:12 PM Not as ridiculously fast as trespassing at the Nevada Test Site where helicopters from Nellis AFB appear with remarkable speed. 19-Sep-20 02:14 PM speaking from experience? 19-Sep-20 02:16 PM Yes. 19-Sep-20 02:16 PM oh wow 19-Sep-20 02:16 PM https://en.wikipedia.org/wiki/The_Conqueror_(1956_film) 19-Sep-20 02:17 PM A classic. 19-Sep-20 02:17 PM I can't find my photo of it right now (new drive) but I was really surprised at the Trinity Site there were zero signs or anything saying not to go there, just a gap in the fence line where the western edge of the straight interior fence meets up with the inner rounded western fence. 19-Sep-20 02:17 PM Based on me being the only person out even walking around the unfenced areas I figured it was best not to push it 19-Sep-20 02:17 PM Some really cool wolf spider burrows with trinitite turrets though! 19-Sep-20 02:17 PM The cringe level watching The Conqueror is OVER 9000. 19-Sep-20 02:19 PM Not as ridiculously fast as trespassing at the Nevada Test Site where helicopters from Nellis AFB appear with remarkable speed. That does not sound like a good day 19-Sep-20 02:26 PM I would like to never be shouted at over a helicopter loudspeaker again, yesplzthankew. 19-Sep-20 02:26 PM AND I WASN'T EVEN TRESPASSING. I was supposed to be at NTS. But I was walking on a road that, eventually, took you to Nellis. That was grounds for the Shoutycopter. 19-Sep-20 02:28 PM I can only imagine you shouting back until the helicopter realizes its mistake and flies back in shame 19-Sep-20 02:28 PM Whips out personal loudspeaker 19-Sep-20 02:29 PM none needed 19-Sep-20 02:29 PM Never argue with flying things with missiles and chainguns. Similar logic applies to dragons. 19-Sep-20 02:29 PM I bet he's yelled at enough people to be heard over a helicopter 19-Sep-20 02:29 PM also I guess that's generally a pretty good rule for life 19-Sep-20 02:32 PM Hey now, I rarely yell at people. The Voice of Command only gets used if in need IMMEDIATE compliance in an IDLH situation. 19-Sep-20 03:30 PM Never argue with flying things with missiles and chainguns. Similar logic applies to dragons. keep your own handy 19-Sep-20 03:30 PM show them you can bite back 19-Sep-20 03:32 PM When I’m around a dragon in two weeks I’ll keep that in mind 19-Sep-20 03:33 PM https://giphy.com/gifs/sandiegozoo-halloween-jack-o-lantern-komodo-KZeDdQ4auOZEajNALF 19-Sep-20 03:33 PM does this count? 19-Sep-20 05:33 PM @GigaSquirrel Hey have you tried how the detector efficiency fitting tool in InterSpec works with your HPGe? 19-Sep-20 05:33 PM I was surprised to learn that they still use a spreadsheet at work do this efficiency calibration by hand 20-Sep-20 12:03 AM I only ever installed interspec the day before yesterday 20-Sep-20 12:03 AM plus I don't have a known good source for effcal 20-Sep-20 12:05 AM And how do you know if a HPGe detector's vacuum is only moderately bad (i.e. the molecular sieve in the cryostat has saturated, but no significant leak that would cause the detector to frost over) 20-Sep-20 12:16 AM condensation and higher crystal temp 20-Sep-20 12:18 AM Hmm, so does all Canberra HPGe detectors come with a crystal temperature sensor? I guess it would come out from the 9 pin connector? 20-Sep-20 12:18 AM Afaik yes 20-Sep-20 12:19 AM And that pinout for that connector is standardized right? Since it should work with so many different amplifiers 20-Sep-20 12:19 AM So you can say plug a 2002 preamp or a 2008 preamp into the same shaping amplifier 20-Sep-20 12:20 AM I am not sure about the pinout, if that's standard 20-Sep-20 12:20 AM but the 2002 has a testpoint to access the sensor 20-Sep-20 12:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/2002_Circuit_description-A9BE0.pdf 20-Sep-20 12:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/2002CP-A49EC.pdf 20-Sep-20 12:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/ln2board-643D1.pdf 20-Sep-20 12:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/TRP-N-BD73D.pdf 20-Sep-20 12:22 AM I see 20-Sep-20 12:23 AM I have no info on the 2008 'tho 20-Sep-20 12:25 AM Here's the schematic 20-Sep-20 12:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F9D1E.png 20-Sep-20 12:25 AM It doesn't show outputs for the crystal temp sensors 20-Sep-20 12:25 AM Oh it might be on a separate board 20-Sep-20 12:25 AM So separate schematic 20-Sep-20 12:27 AM hmm I also can't see a pt100 in the cryostat 20-Sep-20 12:27 AM r101 maybe? 20-Sep-20 12:27 AM would not make much sense 20-Sep-20 12:27 AM also you can measure leakage current through the crystal, that's proportional to temperature 20-Sep-20 12:27 AM and the reason why it has to be cooled at all 20-Sep-20 12:27 AM but that's not worth anything if you don't know the "right" current when it's cold enough 20-Sep-20 12:27 AM IMO if you can do it safely I'd pump the Ge either way, many people forget to do that 20-Sep-20 12:31 AM Yeah it could be a good indicator if the crystal is still good or not. If that HPGe at work has a crystal that needs to be annealed or something, it might be worth more effort than it's worth 20-Sep-20 12:32 AM HPGes only need annealing after they were in high neutron flux 20-Sep-20 12:32 AM don't ask me about the mechanism, but I've been told that you can see that it needs annealing if the risetime is slower 20-Sep-20 12:32 AM I guess slower uhm... hole travel speed? 20-Sep-20 12:32 AM dang it I am still working on my first coffee today, brain isn't really awake yet 20-Sep-20 12:35 AM Doesn't all types of ionizing radiation cause cumulative damage in the crystal that needs to be annealed? 20-Sep-20 12:36 AM I guess neutrons are more likely to cause dislocations via elastic scattering than gammas 20-Sep-20 12:36 AM gammas can mostly ionize, but are not very likely to transfer momentum to the atoms 20-Sep-20 12:38 AM Hmm yeah that makes sense... Most of the energy transfer from gamma is in the form of generating the ionization charges that are collected, unlike protons/neutrons 20-Sep-20 12:39 AM yep 20-Sep-20 12:39 AM don't anneal the crystal unless you know it needs it, because it also causes it to diffuse the P/N layers deeper, making your dead layer bigger 20-Sep-20 12:39 AM baking up to 80°C is safe I've been told 20-Sep-20 12:41 AM Yeah well it would be the last choice. I'd bet I will snatch it before annealing is even seriously considered 20-Sep-20 12:41 AM and it didn't hurt my Ge 20-Sep-20 12:41 AM hmmm 20-Sep-20 12:41 AM oh! 20-Sep-20 12:41 AM if the efficiency changed after it got warm it might be that you've got air in the cryostat and an ice layer has formed on the Ge 20-Sep-20 12:41 AM I vaguely remember reading something about this 20-Sep-20 12:45 AM Hmm we'll know when it's pumped down again. There are so many RGAs lying around and we'll see what's in there 20-Sep-20 12:45 AM Does your cryostat comes with molecular sieve? 20-Sep-20 12:45 AM Aye! 20-Sep-20 12:45 AM Ours definitely does, so I'd think most of the moisture would be absorbed already 20-Sep-20 12:46 AM most ones do, working as a cryopump for better insulation 20-Sep-20 12:47 AM I know for sure the vacuum problem isn't THAT bad 20-Sep-20 12:47 AM Like the detector won't frost over 20-Sep-20 12:47 AM So whatever moisture that got in would be absorbed by the molecular sieve when everything's cold 20-Sep-20 12:50 AM yeah 20-Sep-20 12:50 AM how high is the humidity at your place? 20-Sep-20 12:51 AM We rarely have days that go beyond 80%, whole place is climate controlled too 20-Sep-20 12:51 AM ah, so I guess you won't see any condensation either way 20-Sep-20 12:52 AM Well let me put it another way, when you touch the outside of the cryostat around the detector when the cold finger is in LN2, it isn't like noticeably super cold 20-Sep-20 12:59 AM Hm ok 20-Sep-20 12:59 AM should not be cold at all 20-Sep-20 01:02 AM Well I guess we can look at it with a FLIR next time, compare before and after pump down 20-Sep-20 01:04 AM heh, yep 20-Sep-20 05:45 PM Lol wth what are y'all's experience with radiation detectors like? I've been a reactor operator for 2 years now and I don't follow everything here! 20-Sep-20 07:30 PM There are a couple of people with pretty solid HPGE experience to say the least. 20-Sep-20 08:23 PM Kind of all over the place. Everything from gold foil electrostatic discharge to fission chambers to run of the mill GMs. What are you after? 20-Sep-20 11:19 PM Not much, just what you can do at home as a hobbyist 20-Sep-20 11:25 PM https://www.youtube.com/watch?v=m3oonk1wnHY 20-Sep-20 11:25 PM Seeing those windows flex under vacuum is stressful 20-Sep-20 11:26 PM Seeing a beryllium window flex under vacuum is even more stressful 20-Sep-20 11:37 PM youtube video @LRM Would this have the same properties as non thermal plasma? 20-Sep-20 11:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A7749.png 20-Sep-20 11:41 PM oh god why 20-Sep-20 11:42 PM Who did this? 20-Sep-20 11:42 PM it's from bens video above 20-Sep-20 11:42 PM Oh I'm still watching lol 20-Sep-20 11:42 PM same 20-Sep-20 11:42 PM sorry for the spoiler 20-Sep-20 11:43 PM I think that appears in an earlier video but I do not remember the reason for why it is like that 20-Sep-20 11:43 PM @adammunich Not sure, sorry... 20-Sep-20 11:44 PM I guess he cut it to shape to fit... something 20-Sep-20 11:44 PM but why remove the paper 20-Sep-20 11:45 PM I don't want to guess and be remembering wrong but hopefully it was a good reason 20-Sep-20 11:46 PM ❎ Doubt 20-Sep-20 11:50 PM Hmm I don't remember such a video from Ben showing that source... 20-Sep-20 11:51 PM https://www.youtube.com/watch?v=ccE8e-cyouI 20-Sep-20 11:52 PM Oh that's really old... Yeah I guess the betas might be too high energy for this? 20-Sep-20 11:52 PM Or simply the activity is too low 20-Sep-20 11:52 PM @adammunich I don't think that small glowing blob of air can be called a plasma, there isn't nearly enough current to keep the air ionized to a degree that it is fully conductive. Most of the light you see is probably from the excitation of nitrogen and recombination of ions and electrons, a bit like in a TEM laser 20-Sep-20 11:59 PM I bet it's conductive 20-Sep-20 11:59 PM I had the air around a glowing nichrome wire be conductive 21-Sep-20 12:00 AM Whether it is conductive enough is the question, strictly speaking the definition of plasma goes into debye shielding distance, but I think this is so far from that 21-Sep-20 12:02 AM I think most of the light is actually just from the filament source 21-Sep-20 12:02 AM Any bit of ionizing radiation passing through air creating ion and electron trails can make the air slightly conductive, but not enough to make the overall behavior change. With an industrial scale irradiator, making a non-thermal plasma is very possible though 21-Sep-20 12:02 AM there are a number of chemistry papers that suggest using non thermal plasma to facilitate a reaction and it looks to me like this could work as well 21-Sep-20 12:03 AM It would work very well for surface treatment too, if the power is higher 21-Sep-20 12:03 AM That window would be a dream window for an EDS detector... 21-Sep-20 12:03 AM Go get one with a popped window and find out 21-Sep-20 12:04 AM Hmm, hey if I ever get a HPGe detector and accidentally pop the window, this could be a nice replacement 21-Sep-20 12:05 AM I have a sili detector with a popped window 21-Sep-20 12:05 AM I haven't done anything with it as I picked up an Amptek detector instead of sorting it out 21-Sep-20 12:05 AM The SDD detector or the silicon PIN diode one? 21-Sep-20 12:06 AM Pin diode, the specs on the SDD didn't look like they were worth $2000 more at all 21-Sep-20 12:06 AM I regretted so much that I didn't get the SDD (XR-100CR I think) when they were like $500 21-Sep-20 12:06 AM There was a listing for a few XR-100CR at either $750 or $500 I swear 21-Sep-20 12:06 AM The resolution difference is really big... I think you need SDDs to really do XRF and so on properly 21-Sep-20 12:08 AM It didn't look like it was that different in their marketing materials 21-Sep-20 12:08 AM Well really big in terms of percentage change I guess 21-Sep-20 12:09 AM Like maybe, 10-20% narrower FWHM than PIN diode if I remember correctly. Its real advantage appears to be sample rate / relaxation time. 21-Sep-20 12:09 AM It's faster so for stuff like x-ray guns it can make more sense 21-Sep-20 12:10 AM Sorry, the XR-100CR is the PIN diode one. 21-Sep-20 12:10 AM Look at this plot, near the lower energies, the resolution really makes a difference. 21-Sep-20 12:10 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/energy-resolution-efficiency-x-ray-energy-6FB50.png 21-Sep-20 12:10 AM And yeah the count rate is really high as well, which is again a real advantage 21-Sep-20 12:12 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/received_291171008562517-F41E9.jpeg 21-Sep-20 12:12 AM Here's what 241am looked like 21-Sep-20 12:12 AM The 60keV line is reduced in height presumably because silicon is translucent there 21-Sep-20 12:13 AM But in XRF, you are not looking for peaks near 60 keV 21-Sep-20 12:13 AM Check out the K and L lines for most the light elements, the resolution improvement of SDD really shines there 21-Sep-20 12:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-26A17.png 21-Sep-20 12:13 AM You get like 50% better resolution or more, and for light elements with close energy separations, that makes it possible to distinguish them 21-Sep-20 12:15 AM Ya you're right 21-Sep-20 12:15 AM And I guess these detectors are only made for XRF as the main intended use 21-Sep-20 12:15 AM Efficiency for such a small thing is too low beyond a few tens of keVs... The other use would be EDS I guess 21-Sep-20 12:16 AM I couldn't find any good open source xrf software 21-Sep-20 12:16 AM For analyzing the plots and picking out what looks like what 21-Sep-20 12:17 AM Hmm well try InterSpec 21-Sep-20 12:19 AM Woah now that's what I'm talking about 21-Sep-20 12:19 AM Or just use that periodic table for most common elements 21-Sep-20 12:19 AM Should be good enough if you have some idea of what elemental composition of the thing you're looking at should have 21-Sep-20 12:19 AM For the K-edge peaks, just limit the search for nuclides to "x-rays" and enter the expected energy from the periodic table. Here's an example for silver: 21-Sep-20 12:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4749D.png 21-Sep-20 12:19 AM But with a calibrated detector, just double-clicking on the peaks and looking at the periodic table should tell you enough 21-Sep-20 12:19 AM What are you using as the x-ray source though @adammunich 21-Sep-20 07:39 AM @Mason_Yu I haven't figured that out yet 21-Sep-20 11:18 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5B3FB.png 21-Sep-20 11:18 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2F167.png 21-Sep-20 11:18 AM I can't exactly pinpoint why, but this body counter looks so cursed 21-Sep-20 11:18 AM is it because it looks like a coffin? 21-Sep-20 11:18 AM is it because it says DIY on it? 21-Sep-20 12:04 PM Well, that is definitely one way to do it. On a positive note, it isn't an actually coffin that's been repurposed, as one once was on the Marshall Islands. 21-Sep-20 12:11 PM https://en.wikipedia.org/wiki/File:Stand-up_WBC.JPG lol I love their dummy 21-Sep-20 12:11 PM those L-shaped rods are great 21-Sep-20 01:08 PM As long as the coffing used to make one was not pre-owned then it's not THAT bad. 22-Sep-20 08:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200922_172936-60C6F.jpg 22-Sep-20 08:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200922_173146-674D3.jpg 22-Sep-20 08:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200922_174314-92563.jpg 22-Sep-20 08:49 AM Time for a new detector build, it's a 40*40 mm NaI! 24-Sep-20 03:51 AM I got some trinitite ❤️ 24-Sep-20 03:51 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-948C2.png 24-Sep-20 08:28 AM Nice! 24-Sep-20 08:31 AM very nice indeed 24-Sep-20 08:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-28C1D.png 24-Sep-20 08:38 AM What’s the energy range there? 24-Sep-20 08:38 AM And those look really nice 24-Sep-20 08:38 AM Reminds me I need to get a nicer box for my non-powdered trinitite 24-Sep-20 08:45 AM the peak in the middle is ~662, the one on the right is ~14XX, either / and / or Lanthanum at 1435 / k40 at 1460 24-Sep-20 11:12 AM woohoo, I found Eu152 24-Sep-20 11:57 AM Cool! Would have expected to see Co60 too but actually, on second glace it might be in there just not resolved enough. 24-Sep-20 12:03 PM there is Co60 in there 24-Sep-20 12:03 PM but my LaBr is way too small to see that 24-Sep-20 12:03 PM too low efficiency at high energies 24-Sep-20 12:03 PM I am considering to switch to NaI for this night 24-Sep-20 12:03 PM plus there might just be too many peaks to properly resolve anything 24-Sep-20 12:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2CE11.png 24-Sep-20 12:03 PM have to see if it makes sense to order some new LN2... 24-Sep-20 12:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D1C0A.png 24-Sep-20 12:10 PM bargain 24-Sep-20 12:11 PM I mean yeah 24-Sep-20 12:11 PM this is fairly cheap as far as LaBr goes 24-Sep-20 12:11 PM but... 24-Sep-20 03:26 PM There’s my beauty 24-Sep-20 03:32 PM I so want one 24-Sep-20 03:32 PM that, plus a proper 2% SBA PMT 24-Sep-20 03:32 PM it'll be like 20k for the whole detector, that's just a tad out of my reach 24-Sep-20 03:32 PM 'tho, knowing my luck I'll get my hands on one at some point 24-Sep-20 03:41 PM Hopefully I can swing the budget for trying out growing a couple LaBr3(Ce) crystals in the next few months... lot of process points to still work out though. 24-Sep-20 09:55 PM Ohh that would be so cool! 25-Sep-20 02:08 AM Well, I switched to NaI, the LaBr just has too low efficiency 25-Sep-20 02:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5DFAF.png 25-Sep-20 02:08 AM X-rays, Am241, Eu152, Cs137 25-Sep-20 02:27 AM there sure are some pronounced peaks 25-Sep-20 02:27 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-0B586.png 25-Sep-20 08:29 AM Ok, HPGe experts, is my thinking on this correct: 25-Sep-20 08:29 AM Poor vacuum (saturated getter, not major leak) is the cause of a problem I’m seeing, where bias voltage can be raised for a while, and the detector operates like one would expect (a few tenths of a % FWHM @662 keV). 25-Sep-20 08:29 AM But then above a certain bias voltage the signal gets noisy, like 1.6% FWHM. 25-Sep-20 08:29 AM Continuing to raise further and the signal cuts out completely. 25-Sep-20 08:34 AM can you measure diode current with your preamp? 25-Sep-20 08:34 AM There is a test point that may be related. 25-Sep-20 08:34 AM 2002 preamp? 25-Sep-20 08:35 AM It’s rebranded PGT. 25-Sep-20 08:35 AM Pumping with a drag pump (no baking) put the threshold of good spectrum -> noisy spectrum around 400V. 25-Sep-20 08:36 AM what was it before? 25-Sep-20 08:37 AM Pumping with a turbo, but also no baking put the threshold around 2000V range. 25-Sep-20 08:37 AM so turbo and baking, problem solved? 25-Sep-20 08:37 AM The label on the detector says 4800V. 25-Sep-20 08:37 AM what the hell 25-Sep-20 08:37 AM oh is it the well one? 25-Sep-20 08:38 AM Yes. 25-Sep-20 08:39 AM hmmm 25-Sep-20 08:39 AM Initially, I pumped it with a turbo and baked it, but only for about 2 hours. A month later, operating at 4800 V was possible, but it was in the noisy 1.6% range. 25-Sep-20 08:39 AM About two years later, the threshold moved down to around 2000 V. 25-Sep-20 08:40 AM turbo, bake and 12 hours at least, also leak check if you can 25-Sep-20 08:40 AM Then, drag pumping without baking was done and I got the 400V threshold. (I didn’t know what a drag pump was. It looked like a turbo, so I assumed it was OK.) 25-Sep-20 08:40 AM Then, turbopumping without baking, and the 2000 V threshold. 25-Sep-20 08:40 AM Yeah, I’d really like to bake and turbopump. But I don’t have everything I need to do that, 25-Sep-20 08:40 AM Also, the cryostat passed a He leak test so any leakage has got to be minuscule. 25-Sep-20 08:46 AM which what you're supposed to find with a leak tester 25-Sep-20 08:46 AM it might just be contaminated on the inside causing leakage current 25-Sep-20 08:49 AM I’m trying to understand failure modes. Obviously I should properly bake and pump it, but that gets back to needing to repair that turbo, replace magnetic bearings, etc. 25-Sep-20 08:49 AM A helium leak tester sounds like the perfect tool for pumping down a HPGe Cryostat actually 25-Sep-20 08:49 AM what happend to your turbo that you have to replace magnetic bearings O.o 25-Sep-20 08:50 AM I am relying on other people’s labs and their generosity to troubleshoot. 25-Sep-20 08:50 AM The lab with the heat tape and turbopump was only available to me for a few hours. 25-Sep-20 08:50 AM And they were using a variac to control the heat tape, and a thermocouple to read it. 25-Sep-20 08:52 AM A few hours of pumping and baking might not be enough to desaturate the molecular sieve? 25-Sep-20 08:52 AM So I was standing there for a few hours playing human PID controller. 25-Sep-20 08:52 AM Yeah, I’d agree, a few hours wasn’t enough. 25-Sep-20 08:53 AM Did you measure the final pressure in the cryostat? 25-Sep-20 08:53 AM It was later opened to atmosphere and drag pumped in a different lab that had no heat tape. 25-Sep-20 08:53 AM oh 25-Sep-20 08:53 AM well then it's saturated for sure 25-Sep-20 08:53 AM They had a He leak checker. 25-Sep-20 08:54 AM Yeah there's the problem... Molecular sieve will quickly saturate and it would be as if you've done no pumping and baking before 25-Sep-20 08:54 AM They later turbopumped it without baking. 25-Sep-20 08:54 AM I kind of felt this was a problem, but it wasn’t my lab. 25-Sep-20 08:55 AM pumping without baking does nothing to the sieves 25-Sep-20 08:55 AM The only turbo I own is in pieces awaiting new bearings. 25-Sep-20 08:55 AM also the leak might just be in the pump port 25-Sep-20 08:55 AM You should also valve off the pump and measure pressure increase over time 25-Sep-20 08:55 AM I have a PID, thermocouple, and solid state relay, and will buy heat tape. 25-Sep-20 08:55 AM I don’t have a valve. 25-Sep-20 08:56 AM So how do you plan to seal off the cryostat after you're done pumping? 25-Sep-20 08:56 AM I have a valve opener that was homemade and may be part of the problem. 25-Sep-20 08:56 AM It doesn’t leak significantly. 25-Sep-20 08:56 AM Jostling the packing will cause a spike on a He leak detector but I imagine that’s to be expected with the mechanical feed through for the shaft that engages the detector plug. 25-Sep-20 08:56 AM But the issue is that the detector plug can’t be withdrawn all the way. 25-Sep-20 08:58 AM Oh so you're using the factory seal-off valve... That could be a major problem as well, depending on the style. What I'm suggesting is use a different valve to isolate the system from the pump and observe pressure increase with a gauge 25-Sep-20 08:58 AM So the vacuum path in and out requires navigating loose screw threads. Not good. 25-Sep-20 08:58 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-015FD.jpg 25-Sep-20 09:01 AM no high vacuum gauges?.. 25-Sep-20 09:01 AM I think all seal-off valves can't be pulled all the way out 25-Sep-20 09:01 AM all of mine can 25-Sep-20 09:01 AM It’s a PGT valve. 25-Sep-20 09:01 AM Like the entire valve body can be extracted from the pump and you can see into the cryostat? @GigaSquirrel 25-Sep-20 09:01 AM Aye 25-Sep-20 09:03 AM I think the problem is that this is a homemade valve opener. The plug diameter is larger than the machined part of the valve opener, so it cannot get pulled out. 25-Sep-20 09:03 AM I see. I have only seen two styles of seal-off valves, one which is a two-piece design and only goes part way out, and the other a simple pinched cap 25-Sep-20 09:03 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-34D39.png 25-Sep-20 09:04 AM oh that looks horrible to connect to 25-Sep-20 09:04 AM But definitely put a gauge on there and a simple kf valve @rdpierce 25-Sep-20 09:04 AM This is more horrible @GigaSquirrel 25-Sep-20 09:04 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4D472.png 25-Sep-20 09:05 AM oh wth 25-Sep-20 09:06 AM I think I could design and fabricate a better opener so the plug can be fully withdrawn into the body of the valve opener and withdrawn past the vacuum inlet so there’s nothing in the way of pumping. 25-Sep-20 09:06 AM Alternately, it was suggested that I buy a different design valve and commercially available opener and TIG weld it onto a plate. I pull out the original valve plug and bolt this thing on. 25-Sep-20 09:07 AM got a pic of your plug? 25-Sep-20 09:07 AM is it that style? 25-Sep-20 09:07 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3E96C.png 25-Sep-20 09:07 AM the valve sure looks like it 25-Sep-20 09:10 AM You said the valve opener doesn't leak significantly, does that mean you've helium leak tested it? @rdpierce 25-Sep-20 09:10 AM Yes, that style 25-Sep-20 09:10 AM Yes, the lab was using my opener. 25-Sep-20 09:10 AM When doing the helium leak testing and they shot helium at it. 25-Sep-20 09:11 AM Also, shouldn't you tilt the detector the other way so the molecular sieve is near the bottom and gets baked? 25-Sep-20 09:12 AM By wiggling the packing, they could see a barely perceptible amount of leak. But generally no, it was fine. 25-Sep-20 09:12 AM this is what my opener for this style looks like 25-Sep-20 09:12 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-0D9D2.png 25-Sep-20 09:12 AM the seal is indium btw 25-Sep-20 09:12 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-C95AF.png 25-Sep-20 09:13 AM That's so much more user friendly wth 25-Sep-20 09:14 AM That’s essentially the same as mine but the plug cannot be unscrewed completely and withdrawn beyond the brass block because the diameter is bigger than the copper pipe that makes up the body. 25-Sep-20 09:14 AM That's so much more user friendly wth @Mason_Yu this is the new canberra style 25-Sep-20 09:14 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/img_20200109_164823-FFE91.png 25-Sep-20 09:14 AM screw it in and pull it out 25-Sep-20 09:14 AM That’s essentially the same as mine but the plug cannot be unscrewed completely and withdrawn beyond the brass block because the diameter is bigger than the copper pipe that makes up the body. @rdpierce well then make a new adapter with a bigger pipe 25-Sep-20 09:15 AM Yeah I saw that on your blog, but it doesn't work on either of the styles I've encountered from Canberra detectors of the mid-80s 25-Sep-20 09:16 AM Again. A lot of stuff on the to do list.... fix turbo. Get all the fittings and a steel hose. Get valve to isolate pump from gauge and cryostat. Build better valve opener. 25-Sep-20 09:16 AM But I’m wondering if the electrical symptoms I’m mentioning are vacuum related and explained by what I mentioned. 25-Sep-20 09:16 AM You mentioned possibilities of crystal contamination. 25-Sep-20 09:16 AM Also, I’ve seen a pic of a detector Carl Willis refurbished with a dead fet. It had a mylar sheet insulator that had a hole burned through it from arcing. 25-Sep-20 09:21 AM Yep :D 25-Sep-20 09:21 AM Before I knew the characteristics, I was operating the detector in the 2000V range and seeing 1.6% FWHM. I kept increasing voltage until the signal stopped, at which point I turned off HV. I’m worried about whether that damaged something. 25-Sep-20 09:22 AM It does make sense that when you increase bias voltage, a detector with bad vacuum would have higher and higher leakage current. You'd get noiser signals and at some point it's just too much for the preamp even 25-Sep-20 09:22 AM But your FET is still alive isn't it? 25-Sep-20 09:22 AM if it wasn't he'd get no signal at all 25-Sep-20 09:23 AM In other words, I’m trying to get an idea of overall health of the detector, so I know whether investing in vacuum will fix it, or even with a perfect vacuum setup and valve opener, the HPGe is toast. 25-Sep-20 09:23 AM good way to test the fet is either the test input or just look for microphonics 25-Sep-20 09:23 AM Fet is definitely alive. I can get microphonics and signal at low bias voltages. 25-Sep-20 09:23 AM Signal looks pretty good at low bias. It’s only when a threshold is crossed that I see 1.6% FWHM. 25-Sep-20 09:23 AM Let me check notes, I did some measurements using the test point which I guess is diode current? 25-Sep-20 09:24 AM Leakage current generally increases exponentially with bias voltage 25-Sep-20 09:25 AM I followed the steps in the PGT manual. 25-Sep-20 09:25 AM While noise increases linearly with leakage current 25-Sep-20 09:25 AM So at some point the exponential increase may cause a fast transition. 25-Sep-20 09:25 AM Do you have a crystal temperature sensor output? 25-Sep-20 09:28 AM Following the procedure in the manual, page 3-4 Step 3 – white noise seems more like 300-400 mV. TP 0 to -0.001 V. Step 6 – bias to 100 V. Noise 80-140 mV. TP -0.009 V. Step 7: Bias: 500 V, Noise 30-50 mV. TP -0.024 V. Bias: 1000 V, Noise 20-30 mV. TP -0.032 V. Bias: 1500 V. Noise 15-25 mV. TP -0.036 V. 25-Sep-20 09:28 AM that looks fairly good 25-Sep-20 09:30 AM @rdpierce Can you link the PGT manual please? 25-Sep-20 09:31 AM I don't have a link but can upload. 25-Sep-20 09:31 AM Uploaded to #resources 25-Sep-20 09:31 AM I don't believe PGT has a crystal temp sensor. 25-Sep-20 09:34 AM Oh thanks for uploading that 25-Sep-20 09:34 AM I’ve been looking for PGT documentation 25-Sep-20 09:35 AM What is the preamplifier model? @rdpierce 25-Sep-20 09:35 AM Some of them seem to have a thermistor near the crystal 25-Sep-20 09:36 AM I think it's an RG-11 25-Sep-20 09:39 AM This may be a selectable option and not available on every preamp unfortunately 25-Sep-20 09:39 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-70E8C.png 25-Sep-20 09:39 AM I don't see any connected feedthrough for the termistor. 25-Sep-20 09:39 AM It's been a while, and I can't find a pic of the preamp, but I remember looking for what was wired on the feedthroughs and couldn't find it. 25-Sep-20 09:39 AM I have pics of the preamp but I think they're on my old phone 25-Sep-20 09:47 AM So the test point voltage never goes to 24V at any bias voltage right? 25-Sep-20 09:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B59FC.png 25-Sep-20 10:13 AM I only measured the TP up to 1500 V. The lousy resolution started happening at 2000 V. I didn't check the TP then. 25-Sep-20 10:13 AM Looking at my logs: 25-Sep-20 10:13 AM Attempted to raise voltage. At 2000 V, signal stopped. Backed off to 1750, signal resumed. 25-Sep-20 10:16 AM I think it may be a good idea to repeat this and check the test pin, since the preamplifier is not designed to work above a leakage current limit. 25-Sep-20 10:17 AM 1750 V had lousy FWHM,1600 V was a night and day difference. 25-Sep-20 10:17 AM That requires LN2. I can get it, but it's an ordeal. 25-Sep-20 10:17 AM Do you get LN2 from welding gas supply shops? 25-Sep-20 10:19 AM I have a source. But the detector is in my friend's home lab, I have to collaborate with him to pick up LN2, we have to drive the dewar to get it, pay through the nose for it, cart it up a flight of stairs, etc. 25-Sep-20 10:19 AM Based on existing data I have, I was trying to get an opinion on what's wrong. I'll certainly check this next time I chil it, but it will be a bit before I can chill it again, especially as I'm getting slammed in university with work. 25-Sep-20 10:19 AM Given what we know (saturated getter, awful vacuum) does it seem just vacuum is wrong, and it can explain all this, or are there other areas of concern? 25-Sep-20 10:28 AM I do think the symptoms corresponds to a hot crystal, high leakage current, and the root cause is most likely bad vacuum 25-Sep-20 10:28 AM Please be careful when raising bias voltage when you chill the detector next time, if the crystal is warm, the FET may be easily damaged. Definitely go slow and always check the output from the preamp 25-Sep-20 10:36 AM Speaking of HPGE detectors, would bad cryostat vacuum potentially cause a bias inhibit sensor to trigger? 25-Sep-20 10:36 AM sure 25-Sep-20 10:36 AM I assume it would if it means the detector just couldn't cool enough 25-Sep-20 10:36 AM thanks 25-Sep-20 10:37 AM bias inhibit just measures crystal temp 25-Sep-20 10:38 AM yeah, it just felt odd for whatever reason 25-Sep-20 10:38 AM mostly because it cooled enough for a few hours and then shut back down after a while a bit later 25-Sep-20 10:40 AM huh 25-Sep-20 10:41 AM yeah, was a bit concerning 25-Sep-20 10:41 AM 2002 preamp? 25-Sep-20 10:41 AM that's the only one I've got a circuit for 25-Sep-20 10:42 AM it's clear there is a vacuum issue so that's already going to have to be dealt with, if the issue is still around after that's another story 25-Sep-20 10:42 AM Not sure off the top of my head 25-Sep-20 10:42 AM would have to go check 25-Sep-20 10:43 AM posted my stuff in #resources 25-Sep-20 11:26 AM @GigaSquirrel How much is LN2 per liter delivered where you are? 25-Sep-20 11:27 AM ~2€/l at 50l, including delivery 25-Sep-20 11:28 AM Hmm, prices around here are about the same with delivery, and $1.4/L if I leave the dewar there and pick it up the next day 25-Sep-20 11:28 AM that sounds quite reasonable 25-Sep-20 11:29 AM Airgas prices are above that though 25-Sep-20 11:29 AM But I don't think anyone cares about that price difference, although we go through so many liters per day 25-Sep-20 11:29 AM I'm surprised you don't have your own liquefier 25-Sep-20 11:30 AM Probably upwards of 5 to 10 L/day with like 6 dewars and some other cryogenic systems that's supposed to be close loop 25-Sep-20 11:30 AM Nah, Airgas delivers everything... 25-Sep-20 11:30 AM How large is your campus? 25-Sep-20 11:31 AM I work at Phoenix Nuclear Labs 25-Sep-20 11:31 AM ohhh 25-Sep-20 11:31 AM Yeah I just meant how large is the physical space they take up 25-Sep-20 11:31 AM Liquefier systems are not usually small things for the scale at which they make financial sense to run from the little I know about them 25-Sep-20 11:31 AM At UCI it takes up a decent chunk of one of their buildings 25-Sep-20 11:33 AM There's three locations, the latest new headquarters is about to open, that place will have enough space for a liquefier 25-Sep-20 11:33 AM But yeah definitely not enough space at the current office... But say if we lose 10 L of LN2 per day at $3.5 per L delivered, it's a pretty trivial cost in the grand scheme of things 25-Sep-20 11:33 AM Trivial enough that they won't consider sending an intern like myself to pick up dewars from a welding shop 10 minutes away 25-Sep-20 11:37 AM Every time I get thinking that I would really like to have an HPGe the whole idea falls apart when thinking about keeping it supplied with LN2 as someone unaffiliated with any universities heh 25-Sep-20 11:37 AM Would have trouble passing on one that was a good enough deal even then...but running it would be a planned out thing for sure 25-Sep-20 11:38 AM LN2 cost is pretty insignificant compared to the cost of the detector itself imo... The effort to pick up the LN2 and keep it cold is not 25-Sep-20 11:38 AM The 50L and 30L long hold dewars should keep you going for a couple of weeks at least 25-Sep-20 11:38 AM Do they still manufacture most HPGe crystals in underground facilities? https://core.ac.uk/download/pdf/38618669.pdf 25-Sep-20 11:38 AM This sounds like something they only do for hyper-pure Ge detectors with enormous crystals measured in kg 25-Sep-20 11:38 AM But Canberra started efforts to move HPGe crystal production underground in the 80s, and I struggle to believe there's enough of a market for ultra-low background gamma detectors to warrant something like this 25-Sep-20 11:47 AM Very cool paper 25-Sep-20 01:35 PM aww it's so cute 25-Sep-20 01:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-EF903.png 25-Sep-20 02:35 PM Awww.... I want one. 25-Sep-20 02:35 PM Or a nice cascade of them. Even better. 25-Sep-20 02:35 PM https://twitter.com/nuclearkatie/status/1247005598777896960?s=21 25-Sep-20 02:37 PM the first part will bring way too many bad ideas to people 25-Sep-20 02:37 PM A friend of mine did that once and called his resulting ptfe container крошечный маяк (tiny majak) 25-Sep-20 02:51 PM So it’s not “my” reactor but I’ve ticked one of those boxes 25-Sep-20 02:51 PM I’ve certainly seen a few people doing that first thing though 25-Sep-20 03:08 PM Katie quickly followed up that tweet with a disclaimer not to break any NRC rules.... 25-Sep-20 04:21 PM Nrc ruins all the fun 25-Sep-20 06:20 PM The NRC: We've learned a thing or two because we've seen a thing or two. 25-Sep-20 06:20 PM Alternatively, The NRC: You know we were created to fix Seaborg's problems right? You think you're worse than Glenn? 25-Sep-20 07:05 PM I’m still not sure but if you stay on a low gram scale would that actually be illegal? I can’t quite figure out 10CFR40 on that 25-Sep-20 09:10 PM As I recall, the tables switch to activity and stop talking in terms of mass. It would be Alternatively, The NRC: You know we were created to fix Seaborg's problems right? You think you're worse than Glenn? @funranium is that a Challenge? 26-Sep-20 01:28 AM I want to build an AVLIS 26-Sep-20 01:28 AM (But I'll use it for the separation of Ca isotopes) 26-Sep-20 01:43 AM but it's easy to re-rig/re-configure for some other elements 26-Sep-20 01:43 AM and I'm talking about stupidly tiny amounts 26-Sep-20 01:43 AM only saw "AVLIS" - that's what triggered me 26-Sep-20 01:43 AM (cause I'm workin on such (super small scale) stuff) 26-Sep-20 01:49 AM is there any documentation on the stuff you're working on? 26-Sep-20 02:40 AM make docs 26-Sep-20 02:40 AM na 26-Sep-20 02:40 AM I document it here 26-Sep-20 02:40 AM my plan is making a youtube video about it 26-Sep-20 02:45 AM so we'll get bits of information over the next 5 years until it's finally all done and we get one two minute video where you go over everything? 26-Sep-20 03:06 AM you think it's that difficult? 26-Sep-20 03:06 AM I mean I'm talking about mW laser powers not MW 26-Sep-20 03:06 AM only for the demonstration of the principle 26-Sep-20 03:06 AM not for industrial grade enrichment or something 26-Sep-20 03:06 AM showing the fluorescence peaks for the different isotopes and if their ratio corresponds somehow to the presumed abundance of the sample, calling the experiment a success \o/ 26-Sep-20 03:15 AM you are posting very little, I have absolutely no means to judge your skills ^^ 26-Sep-20 03:16 AM don't assume any skills - expect only failure 26-Sep-20 03:16 AM that's the spirit 26-Sep-20 03:17 AM haven't posted anything on the channel yet 26-Sep-20 03:17 AM but I truly want to change that 26-Sep-20 03:19 AM always happy to see other peoples projects :) 26-Sep-20 08:46 AM I’m disappointed that #2 doesn’t include building your own Calutron. 26-Sep-20 11:42 AM well ... 26-Sep-20 11:42 AM a calutron for reference 26-Sep-20 11:42 AM if I find teh time for building a proper ion source ... 26-Sep-20 11:42 AM (huge for me if I'm considering what I've build so far in the vacuum context) 26-Sep-20 11:42 AM I would also use that calutron rig as a base for an ion implanter of course 26-Sep-20 11:42 AM not talking of x-ray probs 26-Sep-20 01:03 PM TIL a solenoid coil driving balls into a slotted foam board was used as a serious radiation analysis instrument: 26-Sep-20 01:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F7D3C.png 26-Sep-20 01:03 PM A mechanical MCA 26-Sep-20 01:03 PM Known as a kick-sorter 26-Sep-20 01:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3A028.png 26-Sep-20 01:04 PM wait this was actually used? 26-Sep-20 01:04 PM I always thought that it was just for demonstration 26-Sep-20 01:04 PM Yeah, I thought that was a lecture hall instrument / textbook example only 26-Sep-20 01:04 PM or assumed so 26-Sep-20 01:05 PM It's totally serious 26-Sep-20 01:05 PM I would love an oscilloscope that worked like that 26-Sep-20 01:05 PM rofl 26-Sep-20 01:05 PM love it 26-Sep-20 01:05 PM 0.001Hz refresh rate 26-Sep-20 01:05 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Mechanical_Kick-Sorter_MCA-4E8DC.pdf 26-Sep-20 01:06 PM someone should get technology connections one 26-Sep-20 01:06 PM Invented in the Cavendish lab, made as a cheaper alternative to electronic versions, namely sweeping SCAs and so on 26-Sep-20 01:06 PM Vacuum tubes in the beginning of the 50s were pricey, so it made sense 26-Sep-20 01:07 PM this but 8k channels 26-Sep-20 01:07 PM the oldest MCAs I've seen (that weren't a SCA and piece of paper) were the core memory ones 26-Sep-20 01:07 PM new pulse arrives MCA: 26-Sep-20 01:07 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/3q5w39-4963E.png 26-Sep-20 01:13 PM I think the earliest MCA is just made up of stacked SCAs 26-Sep-20 01:13 PM Not the most efficient way to do it, but this was in the 40s. Then there was the kick-sorter, and then Wilkinson invented the Wilkinson type ADCs, and MCA performance improved very quickly from there 26-Sep-20 01:31 PM I am so glad that good, modern ADCs are a thing now 26-Sep-20 01:32 PM Praise transistors 26-Sep-20 04:00 PM Decatrons. 27-Sep-20 10:37 AM Found a picture of my HPGe pumpout.... 27-Sep-20 10:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-C5525.jpg 27-Sep-20 10:40 AM heh I know that one 27-Sep-20 12:26 PM The problem is that my opener won’t allow the plug to come all the way out. 27-Sep-20 12:26 PM So the vacuum is having to work through threads which is really inefficient once vacuum gets low enough that the remaining air quits acting like a gas. 27-Sep-20 12:26 PM Suggestions range from: make a better valve opener to buy a different valve and commercial opener, and weld it to a plate that I can bolt onto this. 27-Sep-20 12:31 PM I vote for make a better opener 27-Sep-20 12:33 PM Something like this: https://www.cryocomp.com/products/vacuum-seal-off-valve-v1000-series/ 27-Sep-20 12:34 PM never change a running system 27-Sep-20 12:34 PM the valve you've got is great, you only need a proper opener for it 27-Sep-20 12:41 PM The other problem is that the spanner doesn’t have a positive lock on the plug, so when I pull it out, I am concerned about how it will fit back into the port. 27-Sep-20 12:41 PM And what orientation am I supposed to pump out in? I think @Mason_Yu implied something about the getter. 27-Sep-20 12:41 PM That pumping it flat on a table is a problem? 27-Sep-20 12:42 PM Oh you just want the heater to be around the molecular sieve 27-Sep-20 12:42 PM I’m assuming that’s at the bottom near the cold finger that goes into the dewar? 27-Sep-20 12:42 PM If you move the detector around, you should hear the particles moving around. Just make sure they are near the bottom 27-Sep-20 12:43 PM Particles? 27-Sep-20 12:43 PM I’ve never opened one of these up. What does it look like? 27-Sep-20 12:43 PM Yeah, you can tilt the detector slightly like you did, but put the block under the detector end, not the cold finger end. I meant molecular sieve balls 27-Sep-20 12:43 PM And with the detector at room temp, I’ve never heard any loose balls in this thing. 27-Sep-20 12:45 PM they may just be glued down 27-Sep-20 12:45 PM I have both here 27-Sep-20 12:45 PM So what way does it need to be tilted? 27-Sep-20 12:45 PM if they're not free moving it doesn't have to be tilted 27-Sep-20 12:45 PM Ok 27-Sep-20 12:45 PM Why would that be necessary for a detector that must operate in a known position and is likely very rarely getting moved? @GigaSquirrel 27-Sep-20 12:45 PM naybe lay it down in a position where the valve won't fall back in 27-Sep-20 12:45 PM Why would that be necessary for a detector that must operate in a known position and is likely very rarely getting moved? @GigaSquirrel @Mason_Yu good question, but no idea 27-Sep-20 12:46 PM Doesn't it just reduced surface area and add another component that can outgas or breakdown over time? 27-Sep-20 12:46 PM maybe they're held in a basket or something? 27-Sep-20 12:46 PM packed tightly so they can't move 27-Sep-20 12:46 PM I’m assuming they are in the lower portion of the dipstick near where the cold finger that goes into the LN2 is? And not up by the detector head? 27-Sep-20 12:47 PM yes 27-Sep-20 12:47 PM Yeah honestly just surround the whole dip stick with heat tape 27-Sep-20 12:47 PM also yes 27-Sep-20 12:47 PM That’s doable. I’ve got a PID now so I can bake it unattended. 27-Sep-20 12:48 PM just don't go over 80°C or the detector might take damage 27-Sep-20 12:48 PM at least that's the temperature I've been told and it worked for me 27-Sep-20 12:49 PM At work they bake HPGe cryostats at 80C maximum as well 27-Sep-20 12:49 PM that's good to know 27-Sep-20 12:49 PM Ok. What are the chances any of the insulators in the can have arced through like the pic from Carl’s HPGe? 27-Sep-20 12:50 PM if it arced through your fet is dead 27-Sep-20 12:50 PM ^ 27-Sep-20 12:50 PM since your fet isn't dead it won't have arced 27-Sep-20 12:50 PM That’s good to know. 27-Sep-20 12:50 PM Bottom line, I need to get a working turbo to pump this. 27-Sep-20 12:50 PM And fab a better valve opener. 27-Sep-20 12:52 PM exactly 27-Sep-20 12:56 PM @rdpierce So you have a working controller for your EXT70H right? 27-Sep-20 12:56 PM I believe so. 27-Sep-20 12:56 PM Is it 24V? If so consider this? https://www.ebay.com/itm/Edwards-Vacuum-Turbomolecular-Pump-EXT255H-24V-dc/114239080468 27-Sep-20 12:58 PM It’s not the 24V version. 27-Sep-20 12:58 PM And the desc for that says Unable to be tested in-house, unit is being sold as is. Some slight damage to the fan, but nothing serious. 27-Sep-20 12:59 PM Hmm, I'm actually tempted to pick one up myself actually, the seller is local to me 27-Sep-20 12:59 PM Must resist urge to pick up a third EXT255H though 27-Sep-20 01:00 PM As soon as I hear slight damage to the fan, I think crash. 27-Sep-20 01:00 PM Think they mean the cooling fan 27-Sep-20 01:00 PM Oh. 27-Sep-20 01:00 PM Which is not really needed unless you operate the thing 24/7 27-Sep-20 01:01 PM I also could strip the SEM for parts. I don’t want to mess with it as its vacuum is functional. But it’s an option. 27-Sep-20 01:22 PM If you make a reasonable offer on both the pump and the controller, you can probably get a working package for <$500 27-Sep-20 03:30 PM I will think about it. I’m also wondering if I can machine a puller for the ring to get the broken magnets out of the old pump. But I am worried about getting them back in and getting everything back together. 27-Sep-20 03:30 PM What I need to replace: outer and inner magnetic bearings, lower ceramic bearing (and machining spacers if it isn’t a standard size), new felt for the oil reservoir, and new oil. 27-Sep-20 03:32 PM I also have a 70-85V EXT255Hi pump 27-Sep-20 03:32 PM I am actually tempted to swap it for the 24V version 27-Sep-20 03:32 PM But I only have one 24V controller, which means I can't run both at the same time 27-Sep-20 06:17 PM Well this doesn't seem quite proper 27-Sep-20 06:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CD59F.png 27-Sep-20 06:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-67FD3.png 27-Sep-20 06:17 PM (yes it's been flagged by now) 27-Sep-20 06:23 PM that sticker is just a decoration 27-Sep-20 06:23 PM means nothing 27-Sep-20 06:23 PM ¯\_(ツ)_/¯ 27-Sep-20 06:23 PM /s 27-Sep-20 06:25 PM Glad to see eBay's listing checking algorithm and people are up to the task as always. 27-Sep-20 06:27 PM I'm just debating if I need to give the Florida Bureau of Radiation Control a call tomorrow 27-Sep-20 06:28 PM That would be polite. 27-Sep-20 06:28 PM yeah, will do then 27-Sep-20 06:33 PM Just in case someone in Florida is breathtakingly stupid enough to try to sell a stolen Troxler gauge on eBay. Ah, the Mother Swamp. [wipes tear] 27-Sep-20 06:37 PM There's a youtube video of the guy (who says flat out he has no idea what it is) going over it, it's been lying around somewhere for long enough the batteries have corroded to hell and back, but at least the handle is locked closed 27-Sep-20 08:02 PM [shudder] 27-Sep-20 09:02 PM i wonder if it would be possible to match it up on the incident map to some device that went missing 27-Sep-20 09:02 PM https://www.nti.org/analysis/articles/cns-global-incidents-and-trafficking-database/ 27-Sep-20 09:02 PM looks like a few missing troxlers in florida 27-Sep-20 09:13 PM It was reported stolen in 2015 27-Sep-20 09:13 PM So yeah, I'm contacting the Florida Bureau of Radiation Control tomorrow 27-Sep-20 09:13 PM https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2016/20160106en.html 27-Sep-20 09:13 PM Relevant report of it's theft 27-Sep-20 09:16 PM Nice find 27-Sep-20 09:27 PM Gold stars like this are awfully nice in the NE field. 27-Sep-20 09:28 PM Imagine stealing something so specific but you can only sell for $2000 27-Sep-20 09:28 PM Is this how art theft works? 27-Sep-20 09:29 PM Gold stars like this are awfully nice in the NE field. hm? 27-Sep-20 09:38 PM Just ruining all the fun ratting out fun stuff in the wild 27-Sep-20 09:40 PM I don’t have an emote appropriate for that statement 27-Sep-20 09:42 PM Lol 27-Sep-20 10:59 PM Having the regulators remember your name but for a good reason is worth its weight in gold in rad work. 27-Sep-20 10:59 PM That's not fun stuff @Treehouseman. That's a [words the filter won't let me say] liability. Those are registered sources we don't like to lose track of. Ever. 27-Sep-20 11:07 PM Oh I fully understand that, but I'd still love to have a source like that in my collection 28-Sep-20 12:06 AM Oh dang 28-Sep-20 12:06 AM that's a pretty hot source 28-Sep-20 12:21 AM I remember that Carl Willis had a 5 mCi Am-Be source he made himself 28-Sep-20 12:21 AM I'm pretty sure Carl did register with the NRC and has a general license 28-Sep-20 12:21 AM How much is too much though? For a person like Carl? 28-Sep-20 12:21 AM https://www.youtube.com/watch?v=ng6NOH8S7Bk&t=258s&ab_channel=CarlWillis 28-Sep-20 06:11 PM The NRC has a general license for small quantities of uranium under § 40.22 28-Sep-20 06:11 PM Does anyone know if one can purchase small U3O8 samples in powdered form? Depleted would be fine. 29-Sep-20 12:51 AM I have this atomic physics idea I want to roll by y'all. How would you make a programmable sensor? Something that can be super sensitive for one element in particular, not a spectrum of elements. Let's say you wanted to measure for lead, or for mercury contamination but not simultaneously. With light you can use a monochromator to selectively excite something and have it stand out. Presumably you could do that with x-ray florescence too? 29-Sep-20 12:54 AM that's atomic physics, not nuclear physics 29-Sep-20 12:54 AM also elements have more than one peak in their xrf spectrum and you want to view as many as possible to make sure you've got the right ones 29-Sep-20 12:54 AM also also what would be the advantage of this over a full spectrum sensor? 29-Sep-20 12:59 AM Photodiodes are really cheap but energy sensitive ones are not 29-Sep-20 12:59 AM Those NDIR co2 sensors are awesome, they selectively look for 4.2 micron light with a boring photodiode. how do we make one for lead? 29-Sep-20 01:03 AM we don't, they work on completley different methods 29-Sep-20 01:03 AM CO2 absorbes light at that specific wavelength, and it always does because it's always this one molecule 29-Sep-20 01:03 AM lead won't do that because it can be in all kinds of different chemical compounds 29-Sep-20 01:03 AM with xrf you send "white noise" to your sample and look what peaks come back due to fluorescence, but you have multiple peaks per element and want so look at as many of them as possible to be as sure as possible that we've got the right ones 29-Sep-20 01:03 AM you can use a monochromator and movable detector to tune it for a single energy, but those are huge and very, very expensive 29-Sep-20 01:03 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/4d9bef67b500f177fd02b8f29ba31c1e9a059b53-722B2.png 29-Sep-20 01:03 AM http://mcff.mtu.edu/acmal/electronmicroscopy/MA_WDS_Basic_Science.htm 29-Sep-20 01:03 AM also I kind of think it's a good thing that not every smartphone or whatever has an x-ray source to look for lead 29-Sep-20 01:03 AM for single element analysis it's way easier to go a chemical route, many organometallic complexes have a very specific color 29-Sep-20 01:21 AM you can use a monochromator and movable detector to tune it for a single energy, but those are huge and very, very expensive @GigaSquirrel Perfect, how do we make them cheaper? 29-Sep-20 01:24 AM by reading up on how they're produced, understanding the mechanics and then changing the one thing we've been looking for in the last 60 years or so on how to finally make crystal growth cheap and easy 29-Sep-20 01:36 AM would a quartz crystall work? 29-Sep-20 01:36 AM I mean many x-ray analyzers are made out of quartz, right? 29-Sep-20 01:38 AM wasn't it Ge something? 29-Sep-20 01:38 AM sapphire should also work and Si waferers? 29-Sep-20 01:39 AM LiF, Quartz or SiO2, InSb, Si, Ge, PET, ADP, Beryl, TlAP, RbAP, KAP and CsAP 29-Sep-20 01:39 AM yeah a Ge wafer would also be an idea? 29-Sep-20 01:39 AM I mean Si, SiO2, Ge, Al2O3 are pretty cheap - and a wafer should work, right? or are common wafers to thin? 29-Sep-20 01:43 AM no idea tbh 29-Sep-20 01:43 AM I haven't read much on WDX so far 29-Sep-20 05:20 AM https://www.crystals.saint-gobain.com/sites/imdf.crystals.com/files/documents/xray-crystals-spectroscopy.pdf 29-Sep-20 06:42 AM ah 29-Sep-20 07:54 PM Which is to say it's been happening, they* are *cheaper and in much wider variety than they once were. 29-Sep-20 11:54 PM but then again with one fixed crystal you only see one line 29-Sep-20 11:54 PM unless you build a complete wdx 29-Sep-20 11:54 PM in which case it's cheaper and easier to do every other test if you're just looking for lead 30-Sep-20 04:24 AM pewbee 30-Sep-20 04:24 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F5AF7.png 30-Sep-20 07:23 AM That’s better than just saying “pube” 30-Sep-20 07:25 AM Thank goodness for the words “howitzer source” 30-Sep-20 07:25 AM I got to read a wonderful description of a calibration procedure for a radioactive gas monitor yesterday 30-Sep-20 07:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-69319.png 30-Sep-20 07:27 AM oh no 30-Sep-20 07:27 AM so I guess calibration with radon isn't good enough? 30-Sep-20 07:28 AM Well we were specifically interested in argon-41 30-Sep-20 07:28 AM fair 30-Sep-20 07:28 AM The new meters specifically ignore radon 30-Sep-20 07:28 AM (New being rather relative) 30-Sep-20 07:29 AM mhh 30-Sep-20 07:29 AM I kinda dislike counters that just gut out parts of the spectrum 30-Sep-20 07:29 AM sure, high amounts of radon and high amounts of fission / activation products in the air are two very different issues, but I still want to know if I have dangerously high amounts of Rn in the air 30-Sep-20 07:32 AM There’s no conceivable way we’d be dealing with alpha contamination so it makes sense to subtract it out to get a clearer beta particle signal to tell if something important is being released. That and there’s already a ton of air turnover in that space 30-Sep-20 07:32 AM Somewhat relatedly it’s a shame that you can’t do alpha/beta pulse height discrimination in plastic scintillators. 30-Sep-20 07:35 AM you can't? 30-Sep-20 07:36 AM I’ve yet to see any reference to it being done 30-Sep-20 07:36 AM Unlike in liquid 30-Sep-20 07:36 AM hmm 30-Sep-20 07:36 AM I've only ever done beta / gamma, but alpha / beta should be possible, if not via phd maybe psd? 30-Sep-20 07:36 AM Maybe 30-Sep-20 07:36 AM alpha should be stopped much quicker 30-Sep-20 07:36 AM https://www.researchgate.net/publication/45504814_Alphabeta_pulse_shape_discrimination_in_plastic_scintillation_using_commercial_scintillation_detectors 30-Sep-20 07:37 AM How’d I miss that 30-Sep-20 07:38 AM or go phoswhich, ZnSe on Plastic 30-Sep-20 07:38 AM True 30-Sep-20 07:38 AM that's how the contamination monitors do it 30-Sep-20 07:39 AM True, I’ve been toying with how I’d do a scintillator based air particulate monitor 30-Sep-20 07:43 AM phoswhich, plus maybe some electrostatic collection 30-Sep-20 07:43 AM is how I'd do it 30-Sep-20 07:43 AM I’d probably have vacuum pump pulling through filter 30-Sep-20 07:43 AM But yeah 02-Oct-20 09:28 AM t h i c c 02-Oct-20 09:28 AM what is it, some glass? 02-Oct-20 09:29 AM Some sorta plastic 02-Oct-20 09:29 AM Just found it on a shelf 02-Oct-20 09:29 AM Density right about 1 02-Oct-20 09:30 AM oh ok 02-Oct-20 09:30 AM the fractures looked more... glassy 02-Oct-20 09:31 AM Yeah, but honestly I’ve got no clue. Might try and figure out so maybe someone can use it 02-Oct-20 12:13 PM (Repost to remove my ID) 02-Oct-20 12:13 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-128AE.jpg 02-Oct-20 03:50 PM Huh. Hunk of plastic scint? 02-Oct-20 05:25 PM Looks like it 02-Oct-20 05:25 PM There was a housing for a neutron detector near it and another much less transparent scintillator 02-Oct-20 07:54 PM Oh also, the gauge was successfully recovered 02-Oct-20 08:04 PM ❗️‼️❗️ 02-Oct-20 08:10 PM And I’ve got a nice email back from the agency I contacted thanking me 02-Oct-20 09:23 PM NICE! You have very much done a good deed. I have a gold star for you. 02-Oct-20 09:23 PM Seriously, cherish that email. 03-Oct-20 12:18 AM Woo! 03-Oct-20 12:18 AM also hm 03-Oct-20 12:18 AM I got my salary 03-Oct-20 12:18 AM and now I'm thinking about selling my 10x20 mm LaBr and building a new 25x25 mm one 03-Oct-20 09:22 AM The struggle is real. 03-Oct-20 09:43 AM it really is 03-Oct-20 09:43 AM but my lathe partly crapped out today (while building a case for another detector), so I'll first have to fix that 03-Oct-20 09:43 AM the nut holding the sled is made from zinc... 03-Oct-20 09:43 AM and since the thread it's running on is non Standard I can't just replace the nut but have to do both the nut and the spindle :v 03-Oct-20 10:16 AM nut holding the sled? i think something is being lost in translation from German there...possibly... 03-Oct-20 10:16 AM whatever part it is hopefully it is not too challenging a repair. parts made out of zinc are usually easily replaced with some oilite bronze or brass 03-Oct-20 10:19 AM the sled sits on the bed, with hte bed functioning as rails for it. It is moved along a threaded rod with some trapezoidal thread on it, there's a nut on the sled that engages with that thread 03-Oct-20 10:19 AM ahh so the carriage and half nut? 03-Oct-20 10:20 AM yeah I went with bronze for the nut 03-Oct-20 10:20 AM no half nut 03-Oct-20 10:20 AM full nut 03-Oct-20 10:20 AM http://www.metalartspress.com/sites/default/files/article-images/Inner-Workings-of-Lathes----Pix-3.jpg 03-Oct-20 10:20 AM are we talking about the cross feed 03-Oct-20 10:20 AM or the carriage 03-Oct-20 10:21 AM carriage 03-Oct-20 10:21 AM 'tho it's this lathe 03-Oct-20 10:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/maxresdefault-B3E09.png 03-Oct-20 10:21 AM "lathe" 03-Oct-20 10:22 AM ahhhh i have only seen those style lathes a couple times where you can move the carriage with that wheel on the right 03-Oct-20 10:22 AM yep 03-Oct-20 10:31 AM it's never too lathe 03-Oct-20 11:45 AM Sonny, true love is the greatest thing in the world. Except for a nice MLT, a mutton, lettuce and tomato sandwich, where the mutton is nice and lean and the tomato is ripe. They're so perky, I love that. But that's not what he said. He distinctly said "to lathe." And, as we all know, "to lathe" means "to turn a cylindrical piece of metal while machining it." So you're probably a grad student who needs a part fabricated for an experiment, and he’s the only machinist in the machine shop.... 03-Oct-20 10:17 PM @GigaSquirrel is that your lathe? 03-Oct-20 10:17 PM I have the same one, but the CNC version 03-Oct-20 11:37 PM It is! 04-Oct-20 07:19 AM Also I am very jealous of what looks to be a mill head or something hanging over the ways, is that what that is? 04-Oct-20 07:29 AM it is, but mine doesn't have it 04-Oct-20 07:29 AM mine is absolute Minimum, not even thread gears 05-Oct-20 02:16 PM https://shop.generationatomic.org/collections/and-all-the-rest/products/felines-for-fission-sweatshirt if that isn't the ideal clothing for @qualia I don't know what is 05-Oct-20 03:32 PM eee <3 05-Oct-20 03:32 PM i'm not usually a sweatshirt person but that mug tempts me 05-Oct-20 03:32 PM also, selling that LaBr3, huh? 05-Oct-20 03:38 PM I guess the price would be well into 4 digits? 05-Oct-20 03:38 PM These chunky 1" x 3" NaI(TI) + PMT combos are much more affordable, though not exactly spectroscopy grade. You get loads of counts though 05-Oct-20 03:38 PM https://www.ebay.com/itm/BICRON-SAINT-GOBAIN-CRYSTALS-AND-DETECTORS-1-12x1-12m3-1-12-l/223613927835 05-Oct-20 06:16 PM i think the LaBr that @GigaSquirrel has was like $350ish? 05-Oct-20 06:16 PM plus pmt, plus machining, etc etc. so probably 05-Oct-20 06:16 PM also i bought one'o those square scintillator assemblies once and it was.. very waterlogged 05-Oct-20 06:16 PM oozing yellow iodine-y slime 05-Oct-20 06:21 PM Ah I guess the crystal is the smallest one these guys sells and there was a pretty decent sponsorship/discount? https://www.ost-photonics.com/product-category/scintillation-crystal-2/labr3ce-scintillator/ 05-Oct-20 06:22 PM ah, $470ish 05-Oct-20 06:22 PM Yeah those NaI crystals were mounted on the bottom of trucks and so on, you have to get pretty lucky, waiting for mine patiently with fingers crossed 05-Oct-20 06:22 PM orly 05-Oct-20 06:22 PM interesting 05-Oct-20 06:22 PM i am highly prone to pulling exact-sounding numbers out of my ass on a whim and everything i say should be taken with a half-cup of salt 05-Oct-20 06:24 PM Shame they don't sell lithium glass scintillators 05-Oct-20 06:24 PM I tracked down a supplier in China for Li glass, but was bombarded with questions of what I am using it for and who am I affiliated with 05-Oct-20 06:53 PM Make your own lithium glass 05-Oct-20 06:53 PM Surely you too can find some improperly disposed of lithium? Or are you supposed to just put jars of it in the trash 05-Oct-20 06:53 PM Where do you get enriched lithium from? 05-Oct-20 06:53 PM Won't work with regular lithium 05-Oct-20 06:55 PM Ah 05-Oct-20 06:55 PM Lithium enrichment is a... dirty process to say the least 05-Oct-20 07:05 PM you can separate molecular isotopes with an optical centrifuge 05-Oct-20 07:05 PM molecules good 05-Oct-20 07:05 PM https://link.springer.com/chapter/10.1007%2F978-3-642-56546-5_95 05-Oct-20 07:08 PM Damn tearing bonds apart by centrifugal force alone 05-Oct-20 07:08 PM Is there an upper pressure limit for the optical centrifuge to work? 05-Oct-20 07:09 PM collisions are happening on the same timescale as the centrifuge at atmospheric pressure 05-Oct-20 07:09 PM so you kinda get screwed over there / lose a lot of molecules to collisions, but it works 05-Oct-20 07:09 PM the naive model for how molecular temperature affects things is "you need to apply enough torque to slow the molecule down, then spin it up" 05-Oct-20 07:09 PM in practice, for molecules like O2/N2 that are strongly bonded you can spin them out of all the occupied states at room temperature. as you heat them up and higher states populate, you need more centrifuge intensity to bring the molecules with it 05-Oct-20 07:09 PM but the centrifuge starts at 0Hz and decays as a half-gaussian 05-Oct-20 07:09 PM I think they tried spinning H2O at 100C and it didn't work, but that was probably because their method was to put water in a small vacuum chamber and bake it. 05-Oct-20 07:19 PM Unfortunately if the process depends on nearly no molecular collisions, cost-effective scaling will be nearly impossible, especially with the laser intensity this requires. Do you anticipate any industrial applications for the optical centrifuge outside the lab? @idmb 05-Oct-20 07:21 PM I imagine at some point someone will try to use it for enantiomer separation of one of those horrendously expensive molecules 05-Oct-20 07:21 PM I think some are like 100k+/gram? 05-Oct-20 07:25 PM I wonder how much a gram of Li-6 would cost 05-Oct-20 07:25 PM At like 95%+ purity 05-Oct-20 07:25 PM But that's like asking how much a gram of plutonium would cost 05-Oct-20 07:25 PM Unfortunately beyond the reach of anyone besides corporations and governments 05-Oct-20 07:29 PM DIY AVLIS is not recommended for the home enthusiast. 05-Oct-20 07:35 PM I hope someone will come up with a clean and scalable method for Li-6 enrichment and restart global production of Li-6 at an industrial scale, both for the sake of fusion energy and also cheaper neutron detectors 05-Oct-20 07:35 PM Behold the ultimate scintillator: https://www.berkeleynucleonics.com/cllbc-scintillators 05-Oct-20 07:35 PM Li-6 material and losses throughout production must account for a significant fraction of the cost of these new elpasolite scintillators 05-Oct-20 08:08 PM But that's like asking how much a gram of plutonium would cost About $4000 dollars last I checked 05-Oct-20 08:09 PM The problem is you can't get any even if you have $4000 to pay 05-Oct-20 08:09 PM So that cost mean nothing to us 05-Oct-20 08:09 PM I’m mostly joking 05-Oct-20 08:12 PM I wonder if you can get Li-6 from some sources somewhere as an individual though 05-Oct-20 08:12 PM I suspect not, even in tiny quantities, even though Li-6 is not an SNM itself 05-Oct-20 08:14 PM Not in America, not imported to America, and not without shenanigans. 05-Oct-20 08:14 PM As Charlie Stross once said, one of the enduring tragedies of the 20th century is that nuclear weaponry happened before commercial nuclear power. A lot of things went funny because of that. 05-Oct-20 08:22 PM is there a good history of nuclear oopsies that should have been catastrophic but weren't because of luck? 05-Oct-20 08:35 PM Wait a sec: 05-Oct-20 08:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-FAEBC.png 05-Oct-20 08:35 PM https://www.americanelements.com/lithium-6-chloride-20227-31-0 05-Oct-20 08:35 PM I wonder if that's just a standard copy pasta that simply replaces the element name 05-Oct-20 08:35 PM I can't find anything on their website that isn't "generally immediately available": https://www.americanelements.com/lithium-6-metal-isotope-14258-72-1 05-Oct-20 09:27 PM There's the DOE, NRC, and IAEA "near miss" incident logs. They aren't so much histories as a catalog. 05-Oct-20 10:03 PM Oh, and on the subject of chemicals for sale, I finally found yellowcake. I just had to broaden my scope of what yellowcake is. I was searching for U3O8, but realized I could find it in ammonium diuranate form. 06-Oct-20 12:03 AM also, selling that LaBr3, huh? @qualia Sorry, decided not to, for now ^^ 06-Oct-20 12:12 AM but I mean it would not be the first time that I make a detector for someone, in case you're interested ^^ 06-Oct-20 12:41 AM I can't find anything on their website that isn't "generally immediately available": https://www.americanelements.com/lithium-6-metal-isotope-14258-72-1 @Mason_Yu https://www.sigmaaldrich.com/catalog/search?term=20227-31-0&interface=CAS%20No.&N=0&mode=partialmax&lang=en®ion=US&focus=product 06-Oct-20 12:45 AM also there's this on ebay but sadly it's natural lithium and not enriched 06-Oct-20 12:45 AM https://www.ebay.de/itm/184382978379 06-Oct-20 12:45 AM https://scintacor.com/products/6-lithium-glass/ 06-Oct-20 12:46 AM I don't know if Sigma-Aldrich would sell that to individuals. Also I saw that eBay listing already 06-Oct-20 12:47 AM Looks like 6Li has a higher affinity for Hg than 7Li 06-Oct-20 12:47 AM Yeah, that's the principle behind the colex process 06-Oct-20 12:47 AM Similarly, it has a higher affinity for certain (very expensive) crown ethers as well 06-Oct-20 12:48 AM also the Li you can buy is a bit depleted fiy 06-Oct-20 12:48 AM Using crown ethers yields a cleaner process but the raw chemical cost is extremely expensive 06-Oct-20 12:48 AM Potentially doable at home if you have the patience and the cash 06-Oct-20 12:49 AM I bet you could electrolyze Li salts with an Hg electrode and get somewhere useful that way. 06-Oct-20 12:49 AM also if you want Li6 for neutron detection why not go with boron? ^^ 06-Oct-20 12:49 AM iirc natural boron has a higher cross section than natural lithium, saving you the enrichment 06-Oct-20 12:51 AM The decay time of lithium scintillators is extremely fast, it's the only real option for ToF spectroscopy without a super long beam line 06-Oct-20 12:52 AM ah I see 06-Oct-20 12:52 AM But for general detection, BF3 or Soviet He3 tubes are much more cost-effective just from an efficiency point of view 06-Oct-20 12:52 AM I'm actually tempted to get a quote on a tiny elpasolite scintillator 06-Oct-20 12:52 AM For use with a SiPM 06-Oct-20 12:52 AM https://www.dynasil.com/product-category/scintillators/cllbc-gamma-neutron-scintillator/ 06-Oct-20 12:53 AM I wonder if it's possible to boron load a fast anorganic scintillator 06-Oct-20 12:54 AM As far as I know they've only got good results with these Li-6 doped inorganic scintillators 06-Oct-20 12:55 AM oh I'm talking about getting results at all 06-Oct-20 12:55 AM Whether it's in NaI(TI+Li) or those elpasolite 06-Oct-20 12:55 AM not for tof or anything 06-Oct-20 12:56 AM Scintillator physics/chemistry is crazy man 06-Oct-20 12:56 AM Yeah... 06-Oct-20 12:56 AM I have no idea if it would work at all or why it wouldn't work 06-Oct-20 12:56 AM But if Li-6 is cheaper, than those new dual mode scintillators would absolutely outclass He-3 tubes in price and performance 06-Oct-20 12:56 AM My hypothesis is that boron is simply a hard material to incorporate into a crystal lattice without messing it up 06-Oct-20 01:05 AM Honestly with those new green laser diodes now, you can pump a tunable dye laser and do AVLIS if you really wanted to. 06-Oct-20 01:06 AM for inorganics sure, not gonna touch a lattice because I have no idea what I am doing, but inorganics aren't / don't have to be single crystal, right? 06-Oct-20 01:08 AM It doesn't have to be a single crystal, but microscopic defects within the crystal lattice might mess up the band structure and cause a decreased light yield 06-Oct-20 01:08 AM For all of these inorganic crystals, I think it is desirable to have a precisely controlled amount of one activator. Ce3+ is the best thing we've found yet, and they're essentially finding band structures in a crystal that creates the maximum amount of space for these activators 06-Oct-20 01:08 AM It is important to have one and only one activator. Boron is a common p-type dopant, so it would probably mess up the band structure somehow 06-Oct-20 01:08 AM Now if the boron is part of the crystal lattice (i.e not a dopant), that's another question 06-Oct-20 10:55 AM I had an idea, and it’s interesting but might be bad bordering on cursed. It does appear to be legal according to the general license in NRC § 40.22 so I think it’s safe to ask about it here. I wanted to ask here to get opinions. 06-Oct-20 10:55 AM I’m wondering about taking yellowcake in the form of ammonium diuranate, although other forms might work too, and putting it into a non-dispersible solid form by blending it into an epoxy. 06-Oct-20 10:55 AM Then casting the epoxy in small silicone molds into regular solids with, say, 4, 6, 8, 10, 12, and 20 faces. 06-Oct-20 10:55 AM The molds would have numbers engraved on the faces for easy identification. 06-Oct-20 10:55 AM I am wondering about risks here. If said solids were regularly dropped and rolled on a hard surface, would they be likely to leave any significant or measurable contamination? 06-Oct-20 10:55 AM And be safe to handle without gloves? (I’m assuming reasonable adults here, nobody is going to put them in their mouth or anything, but at the same time, I’d hope that they would be inert to such an extent that eating or handling food while also handling them would be safe.) 06-Oct-20 10:55 AM I’ve been thinking if it is possible to encapsulate them further in normal epoxy, but trying to do that in a larger mold would be tricky to do while keeping them centered, and I imagine brushing epoxy on to each face would make the faces uneven, impairing their ability to roll across a surface. Some kind of spray sealant might be a better option, but I’m out of my experience level here. 06-Oct-20 11:26 AM I think it’d probably be best to use depleted uranium if you can find it, just for reduced activity. Im mostly sure you couldn’t sell them (though that’s not really an issue) I’m not going to comment much on the legality other than having always felt weird about the interpretation versus wording of the general license in 10CFR40. I think you might have to just make one while being very careful about dust collection and contamination control then wipe test it for removable contamination once done. 06-Oct-20 11:30 AM To be clear, this is a non-commercial pursuit. I am certainly not proposing listing this on Etsy. 06-Oct-20 11:30 AM It’s also quite some time out if it were going to happen. 06-Oct-20 11:30 AM I’ve got a sensitive alpha scint designed for detecting surface contamination. So wipe testing the items, and checking the surface on which they roll is possible. But the effort involved in creating this is pretty high, so I was trying to get an idea of the probability of success vs. creating a contamination problem. 06-Oct-20 11:30 AM And, ultimately, it’s not a good way to keep friends if you are the reason their dining room table needs to be disposed of as rad waste. 06-Oct-20 01:16 PM Should be safe to handle without gloves once you finish and clean them off of the ambient contamination of your workshop. Really, the likelihood of shedding that is appreciable enough to be a heavy metals uptake concern (because radiological concerns aren't the driver here) which then transfers for food uptake is only slightly higher than the concern level as using Fiestaware or depression glass because of bioavailability of that particular chemical form. Deeper embedding would be better if you can and give them a complimentary felt lined rolling tray as long as you're making things; felt is quite good at catching shedding if there is any. 06-Oct-20 03:31 PM That’s a good thought. 06-Oct-20 03:31 PM Deeper embedding is something I’m thinking about how to achieve. I may reach out to some dice makers to find if there is any clearcoat compatible with epoxy resins. 06-Oct-20 03:35 PM Perhaps pre-encapsulation? Make a clear epoxy spherical mold and then form your dice around that? 06-Oct-20 03:35 PM This, incidentally, is how I've seen a variety of fuel fab samples presented. 06-Oct-20 03:37 PM The problem is keeping the piece centered in a mold while resin is poured around it. I also won’t have access to fiddle with it while it cures because it’s got to go in a pressure pot to keep out bubbles. 06-Oct-20 03:37 PM Pelletization! That's the term I was looking for. 06-Oct-20 03:39 PM Yeah, a spherical pellet would be cool but from what I’ve seen when people try to put things in dice, they seem to sink to the bottom, and are almost always off center. 06-Oct-20 03:40 PM Radial support spokes, that you can pretend are control rods, to the vertices to keep it in place maybe? 06-Oct-20 03:49 PM I’m also looking at biggest contamination risk while making them. Pouring powder into resin while mixing is one area of concern. The second is finishing. I don’t have direct experience here to know how the mold finish looks, and if flashing can be removed easily by cutting, or if sanding is necessary. If any kind of sanding is needed, I’d imagine doing it wet would reduce the possibility of airborne dust. And rinsing the dice in running water would get any mobile contaminants off? 06-Oct-20 04:38 PM For hpge preamps using 9 pin power supplies, how standard are the preamp voltages across manufacturers? 06-Oct-20 04:38 PM or more accurately pin positions 06-Oct-20 04:52 PM I think they’re fairly standard for +/- 12, +/- 24. I think I’ve seen a case where one of two grounds might not be connected. You may also have manufacturers try to stick something funny, like a detector temp pin, in there. I’m not very sure about +/- 6. 06-Oct-20 04:52 PM I remember being upset at a SpecTech UCS-20 box which supposedly had a 9 pin power connector, but it was missing a serious amount of stuff. I think it worked for my NaI but would be incompatible with my HPGe which was part of what prompted me to go NIM. 06-Oct-20 05:10 PM That plus UCS-20 was negative polarity only. 06-Oct-20 08:15 PM @rdpierce I have seen people cast powder specimens into resin inside clear pill capsules which might be an option for you. Have not seen it done in dice shape specifically though. You would have to do some testing to get the timing right for when to put the item in and when to pour the top layer with your specific choice of resins. 06-Oct-20 08:16 PM That’s an interesting thought. 06-Oct-20 08:16 PM The trouble is that I can’t just pour one layer, wait till it gets very viscous, embed an object, and pour another layer. 06-Oct-20 08:16 PM The resin gets poured and the whole thing goes into a pressure pot for curing. 06-Oct-20 08:19 PM Ahh I have not worked with that kind of resin before. Probably would need to find another option then 07-Oct-20 01:40 AM Hey does any else have one of those Amptek dp5 MCA boards 07-Oct-20 01:40 AM I got the python program actually working and can put up a git repo for it 07-Oct-20 01:40 AM Their original implementation was hella broken 07-Oct-20 10:13 AM Anyone have any guesses as to what the radiation trefoil is about on Russia's Su-57 jets? Just saw a photo of one that had it and there are a couple other examples too. Can't really come up with what a modern jet would have in it that is radioactive. https://www.thedrive.com/content/2020/10/FINAL-TOPSHOT.jpg?quality=85&width=1440&quality=70 07-Oct-20 10:13 AM Another one: https://cdn.jetphotos.com/full/6/88797_1586002756.jpg 07-Oct-20 10:14 AM Xrays from radar tubes? 07-Oct-20 10:14 AM I doubt that but the location matches 07-Oct-20 10:16 AM Definitely a possibility but you would hope that their radar systems do not produce ionizing radiation that close to the pilots and strong enough to require a warning 07-Oct-20 10:23 AM Russia 07-Oct-20 10:40 AM but russians are not thaat bad to highly trained HR 07-Oct-20 10:41 AM I say that's a death ray 07-Oct-20 11:01 AM I’d imagine it’s a warning for if the cover is being removed by ground crew 07-Oct-20 11:09 AM Radar tube TX protection trap's in many military radars are radiactive 07-Oct-20 11:09 AM In the west it was usually Tritium, but the soviets have also used Strontium and Cesium in that place. 07-Oct-20 11:09 AM The idea is to lower the breakdown voltage in the protective element, so that it arcs and the arc then acts as a short circuit, protecting the radar receiver from the transmitted pulse. 07-Oct-20 11:09 AM I gave the one I had to a friend. 07-Oct-20 11:09 AM Tho that one did not have any markings, and still reportedly was slightly active. 07-Oct-20 11:09 AM But that one would have likely been tritium filled and had mostly decayed. Got it along some other soviet radar parts in a surplus lot. 07-Oct-20 11:18 AM also DU weights perhaps? 07-Oct-20 11:18 AM alsoalso thorium in the turbines 07-Oct-20 11:32 AM Don't think it is DU weights, something related to the radar systems seems most likely given the location (saw another photo where the tail has the warnings too and there is radar gear there) 07-Oct-20 11:32 AM Just not sure if it is even possible to get ionizing radiation out of radar systems to the level of being a hazard. Have heard that the nonionizing radiation can be hazardous in the past but sorta different mechanisms involved 07-Oct-20 11:33 AM non ionizing radiation at enough power is just holding a 100W lightbulb in your hand or standing in a microwave, depending on the frequency 07-Oct-20 11:33 AM but a trefoil is for ionizing only 07-Oct-20 11:34 AM That is what has me confused 07-Oct-20 11:34 AM back in the day x-rays from radar were an issue, but I am not sure how it is today 07-Oct-20 11:35 AM https://en.wikipedia.org/wiki/Byelka_(radar) think this is the radar system used by the Su-57 07-Oct-20 11:35 AM so X band and L band...nothing about ionizing radiation though 07-Oct-20 11:36 AM early radar systems were tube based with high voltages involved, high voltages in vacuum always create x-rays 07-Oct-20 11:36 AM the issue was not the radar itself but the circuitry required to produce the microwaves 07-Oct-20 11:36 AM but I bet the modern stuff is all solid state now with nowhere close to the voltages required for spicy light 07-Oct-20 11:40 AM Yep which is exactly why the trefoil caught my eye and got me curious 07-Oct-20 11:43 AM hehe 07-Oct-20 11:56 AM https://www.radartutorial.eu/06.antennas/Branch%20Duplexer.en.html#p1 07-Oct-20 12:08 PM is that the modern method? 07-Oct-20 12:08 PM the radar kinds looks like a phased array to me, but this really isn't my area so I might be totally wrong 07-Oct-20 12:30 PM There could be other equipment there too 07-Oct-20 12:30 PM And other radars 07-Oct-20 12:30 PM like there is going to be some EW jammer stuff and others for self protection 07-Oct-20 12:30 PM And those have receivers too. 07-Oct-20 12:30 PM Who knows 07-Oct-20 12:32 PM I most certainly don't 07-Oct-20 12:37 PM Unrelated, I’ve got a detector that’s gone from working fine to after a repair not responding properly when i send pulses into it to check the calibration. It’s my personal gm detector and an internal piece of coax failed so I replaced it with what I thought would be a working replacement but now I’m wondering if that might have had something to do with it. 08-Oct-20 12:40 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201008_093829-413B0.jpg 08-Oct-20 12:40 AM woo new thingie for the lathe 08-Oct-20 12:40 AM not sure if the 3 mm was a good idea, maybe should have gone with 2 mm 08-Oct-20 12:40 AM the original thingie is drumroll 08-Oct-20 12:40 AM 2.5 mm 08-Oct-20 12:40 AM bleh 08-Oct-20 07:11 AM Clearly you just need to throw them on the lathe and turn them down 08-Oct-20 07:18 AM Are you sure it is 2.5 mm and not 2.54mm? 08-Oct-20 07:44 AM Yes, because the scale on the knob to turn said spindle is marked to 2.5 08-Oct-20 07:44 AM and I live in Germany and everything here is metric 08-Oct-20 10:08 AM This reminds me of the annoying Soviet ICs with 2.50 mm pin spacing.... 08-Oct-20 10:33 AM I guess that works with 8 pin, but will be a close call with 14 or bigger 09-Oct-20 01:27 PM It looks like I'm getting two HPGe detectors 09-Oct-20 01:27 PM UC Davis surplus 09-Oct-20 01:27 PM hell yeah, congrats! 09-Oct-20 01:27 PM In what condition are they? 09-Oct-20 01:27 PM Low energy ones, both have beryllium windows, condition unknown 09-Oct-20 01:27 PM ohh neat 09-Oct-20 01:28 PM Windows look fine 09-Oct-20 01:28 PM Need to find the right dewar now and well, build up a better NIM bin lol 09-Oct-20 01:28 PM just feed the preamp signal into a pitaya 09-Oct-20 01:28 PM Home made shaping amps won't do it probably 09-Oct-20 01:28 PM Or that 09-Oct-20 01:28 PM Having HPGe is a good excuse for NIM bin though 09-Oct-20 01:29 PM oh absolutely 09-Oct-20 01:29 PM congrats! 09-Oct-20 01:30 PM Not 100% confirmed yet, but it should be confirmed over the weekend 09-Oct-20 01:30 PM good luck 09-Oct-20 01:30 PM I am still waiting on some parts for my low energy one 09-Oct-20 01:30 PM No idea what the crystal size is, looks like both are planar detectors 09-Oct-20 01:30 PM got any pics you can share? 09-Oct-20 01:37 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-99342.png 09-Oct-20 01:37 PM Detector 1 with big window 09-Oct-20 01:37 PM Two with a slightly smaller window 09-Oct-20 01:37 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2FD8C.png 09-Oct-20 01:38 PM ohh old style 09-Oct-20 01:39 PM From the 80s I believe or early 90s 09-Oct-20 01:39 PM No part number on either, stickers are gone 09-Oct-20 01:39 PM sure they're not Ge(Li)? 09-Oct-20 01:39 PM Yep confirmed they are HPGe 09-Oct-20 01:39 PM great 09-Oct-20 01:40 PM Unless I've been lied to lol 09-Oct-20 01:40 PM One has 2008 preamp, the other is 2002 09-Oct-20 01:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B4C78.png 09-Oct-20 01:40 PM well there's a chance at least one is Ge 09-Oct-20 01:41 PM Canberra I assume looking at them 09-Oct-20 01:41 PM Yep 09-Oct-20 01:41 PM Anyone got details on model numbers for those detectors? 09-Oct-20 01:41 PM It looks like both have been fixed at some point 09-Oct-20 01:41 PM I don't think they attach beryllium windows with epoxy from the factory? 09-Oct-20 01:42 PM (And hmm, how do I convince my boss to get rid of any of the old detectors) 09-Oct-20 01:42 PM The orange epoxy? 09-Oct-20 01:42 PM That's normal 09-Oct-20 01:42 PM Good to know actually! Hopefully they are not detectors that needed frequent repairs 09-Oct-20 01:42 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-4BCF1.jpg 09-Oct-20 01:43 PM I tried convincing my boss, but realized it was futile... 09-Oct-20 01:43 PM Big window on that guy 09-Oct-20 01:43 PM I kind of want to poke that 09-Oct-20 01:43 PM no 09-Oct-20 01:43 PM Me too lol 09-Oct-20 01:43 PM Can you see the vacuum pulling down on it 09-Oct-20 01:43 PM bad Gigabecquerel 09-Oct-20 01:43 PM It does have the tiniest bit of inward bend if I remember correctly 09-Oct-20 01:43 PM I need to stick a cover on that one 09-Oct-20 01:44 PM I hope both of these detectors have good cryostat vacuum... Both of them have the strange stubby seal off valve as the old detector I've seen at work 09-Oct-20 01:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B5577.png 09-Oct-20 01:44 PM This kind 09-Oct-20 01:45 PM oh so that's where you got them 09-Oct-20 01:45 PM Not from work lol 09-Oct-20 01:45 PM They wouldn't give it to me 09-Oct-20 01:45 PM sure they're not Ge(Li)? you wouldn't know how to confirm one way or the other would you? 09-Oct-20 01:46 PM not sure, no 09-Oct-20 01:46 PM I tried convincing my boss, but realized it was futile... there are so many inoperable detectors on a shelf, but it's not like I have the space or money for the rest of the equipment needed (Patrick, you didn't see anything) 09-Oct-20 01:46 PM I have absolutely no idea how far the stuff drifts, maybe it's completely ohmic, maybe it's a terrible diode? 09-Oct-20 01:46 PM They would rather just put the detector on a turbo all the time 09-Oct-20 01:46 PM idiot me didn't think about measuring that when I got my GeLi 09-Oct-20 01:46 PM install a permanent ion getter 09-Oct-20 01:47 PM I'll just have to dig into model numbers and probably make some phonecalls 09-Oct-20 01:48 PM I think most GeLis are probably dead if kept at room temp for a really long time right? It should drift a lot worse than HPGe? 09-Oct-20 01:48 PM yes 09-Oct-20 01:48 PM yes 09-Oct-20 01:49 PM HPGe should be ok stored at room temperature if voltage wasn't applied warm, GeLi is most likely dead if it warms up even briefly 09-Oct-20 01:50 PM a few hours warm should work 09-Oct-20 01:50 PM not good but no death sentence 09-Oct-20 01:50 PM Man this would be great as an EDS (I hope) 09-Oct-20 01:50 PM Oh, certainly 09-Oct-20 01:50 PM I have a free port on the side of the SEM 09-Oct-20 01:51 PM oh yes 09-Oct-20 01:51 PM Need digital acquisition first 09-Oct-20 01:51 PM After I bought the Red Pitaya yesterday everything seems like it can be solved by a Red Pitaya 09-Oct-20 01:52 PM you did get the -14 version, right? 09-Oct-20 01:52 PM also yes 09-Oct-20 01:52 PM Yeah 09-Oct-20 01:52 PM Only needed 14 bits for the camera 09-Oct-20 01:53 PM and for the Ge 09-Oct-20 01:53 PM You don't need a shaping amplifier at all? 09-Oct-20 01:53 PM Just literally preamp straight into the MCA is good??? 09-Oct-20 01:54 PM it can do what they call averaging which basically works as a digital filter 09-Oct-20 01:54 PM haven't tried it with the HPGe yet, but with the LaBr it definitely does something 09-Oct-20 01:54 PM I still want stuff like baseline restoration and so on 09-Oct-20 01:55 PM got within 0.03% to the system with nim amp and shaper 09-Oct-20 01:55 PM Hmm, yeah really good for something handheld 09-Oct-20 01:57 PM I really need to get some more ln2, but I don't want to do that before I repaired my Planar 09-Oct-20 01:58 PM I might put a dewar in the back of a Uber and go to the airgas store to fill it... 09-Oct-20 01:58 PM Just slightly sketchy 09-Oct-20 01:59 PM should work just fine 09-Oct-20 01:59 PM just don't have an accident 09-Oct-20 01:59 PM which is generally a good tip when driving 09-Oct-20 02:00 PM And open the windows just in case 09-Oct-20 02:00 PM yes, absolutely 09-Oct-20 02:02 PM I kept hearing horror stories from a liquid nitrogen ice cream shop with employees handling LN2 with basically no ppe 09-Oct-20 02:02 PM And transporting small dewars in personal vehicles to events the company was catering 09-Oct-20 02:10 PM While the DOT answer is OMG DO NOT DO THIS, your choice of dewar will make things a bit safer. Also, be prepared for your Uber to leave you there. 09-Oct-20 02:10 PM DOT? 09-Oct-20 02:10 PM my friend used to work at one of those places, they have a port for Airgas fillups right on the front of the building. 09-Oct-20 02:10 PM The dewar will likely be there overnight 09-Oct-20 02:10 PM department of transit 09-Oct-20 02:11 PM Different driver then. Less likely to leave you standing there. 09-Oct-20 02:11 PM as far as I'm aware no one has gotten hurt yet, the leidenfrost effect at LN2 temps is really strong 09-Oct-20 02:12 PM You do not tempt fate with gas expansion in confined spaces if you don’t have to. 09-Oct-20 02:12 PM Especially with an innocent bystander (the driver) 09-Oct-20 02:12 PM suffocation risk with N2 is real I hope people keep their windows open 09-Oct-20 02:13 PM hey at least we have the little gates to block off elevators when sending dewars up and down 09-Oct-20 02:13 PM That is indeed why you don’t ride with them. 09-Oct-20 02:13 PM I like to fill thermos with liquid oxygen and hand people a glass of fresh air 09-Oct-20 02:14 PM The former cryotech is not impressed. 09-Oct-20 02:15 PM I don't really have many other options without paying hundreds of dollars in transport alone 09-Oct-20 02:15 PM sometimes that's the cost 09-Oct-20 02:16 PM The former cryotech is not impressed. @funranium one of my bucket list projects is to make the brightest camera flash in history with a cloud of O2 droplets and Mg powder, to take a nighttime flash photo of mount diablo 09-Oct-20 02:17 PM That would be deeply inconsiderate, Adam. 09-Oct-20 02:19 PM mazda used to make enormous Mg flash lamps for this purpose, taking photographs from airplanes 09-Oct-20 02:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/wwR1L8hlzeW2WaCh4beqXJ86XfIRdar4nmUOhfC5Zt-CB576.png 09-Oct-20 02:20 PM I don't really have many other options without paying hundreds of dollars in transport alone @Mason_Yu doesn't your supplier offer delivery? Here it's like 20 bucks and they'll drive their 1000 liter dewar everywhere in the city 09-Oct-20 02:20 PM Nope, unfortunately not to a home address 09-Oct-20 02:21 PM :/ 09-Oct-20 02:21 PM got a company physically close to you? 09-Oct-20 02:21 PM maybe ask them if you can arrange some deal 09-Oct-20 02:21 PM They deliver 1000 L dewars to work at 60 cents/L, but they won't let me fill there 09-Oct-20 02:21 PM And universities gives this stuff out for free 09-Oct-20 02:21 PM To students who know the techs well only of course 09-Oct-20 02:23 PM or students with pis that don't care 09-Oct-20 02:23 PM someone made their own joule thomson N2 generator with home depot parts http://homemadeliquidnitrogen.com/ 09-Oct-20 02:24 PM The swinging pressure nitrogen separator can't really be scaled down 09-Oct-20 02:24 PM Not too excited to work with super high pressures, I am also a terrible welder 09-Oct-20 02:24 PM didn't you get that cryo setup? 09-Oct-20 02:24 PM That too 09-Oct-20 02:24 PM the one I originally bought but the seller bodged the delivery? 09-Oct-20 02:25 PM It was literally still on its way to you when it was sold to me 09-Oct-20 02:25 PM rofl 09-Oct-20 02:25 PM still got my address on it? XD 09-Oct-20 02:25 PM It got stuck at the logistic company, had all of your paper work with it 09-Oct-20 02:25 PM Yep 09-Oct-20 02:25 PM Well they taped over it with my paperwork at least 09-Oct-20 02:26 PM glad it landed with someone sensible 09-Oct-20 02:26 PM what happened to that sniping rule 09-Oct-20 02:26 PM It's still a pain to run 09-Oct-20 02:26 PM fair 09-Oct-20 02:26 PM I think you stated on here that you couldn't get it? 09-Oct-20 02:26 PM what happened to that sniping rule @idmb sniping is still not allowed, this was a different situation 09-Oct-20 02:26 PM Yeah, I bought it, the seller didn't care about anything and shipped it in a way there it had no chance of ever getting to me and after the first thing messed up ebay automatically refunded me and the seller put it back up for sale 09-Oct-20 02:42 PM I do want me a counter or three 09-Oct-20 02:42 PM Just bought a new radio, so might as well consider something similar with counters. 09-Oct-20 02:43 PM four! 09-Oct-20 02:45 PM Lol 09-Oct-20 02:45 PM The radio was a 200eur impulse purchase. It's a Yaesu FT-817 with the TCXO option installed. Neat little thing and perfect for my uses. 09-Oct-20 02:46 PM I see you're getting radio-active 09-Oct-20 02:47 PM lol 09-Oct-20 02:47 PM I'm somewhere between 50-100 radio's 09-Oct-20 02:47 PM And yea I'm more into non-ionizing radiation 09-Oct-20 02:47 PM But I should finish that counter built around that cheap and deaf soviet GM tube. 09-Oct-20 02:47 PM And then start thinkign about the tubes for the next GM counters 09-Oct-20 02:47 PM And maybe building an ion chamber detector 09-Oct-20 02:48 PM Never too many radios huh 09-Oct-20 02:48 PM Air ion chamber is pretty easy to build 09-Oct-20 02:48 PM But not exactly a counter 09-Oct-20 02:50 PM yeah, not really 09-Oct-20 03:33 PM 817 is a nice radio too 09-Oct-20 03:33 PM If slightly long in the tooth 09-Oct-20 04:00 PM Yeah 09-Oct-20 04:00 PM But still a decent IF radio for microwave stuff. Especially after I MARS/CAP mod it >:) 09-Oct-20 05:56 PM yeah, certainly 10-Oct-20 04:16 PM https://www.youtube.com/watch?v=j-tjRh_l0Do&ab_channel=CarlWillis 10-Oct-20 04:16 PM Finally, a new video from Carl, and a good one too. Makes me sad I didn't get to operate the reactor at my school before it was shut down 10-Oct-20 07:35 PM wow, that's simultaneously really foreign and incredibly familiar 10-Oct-20 07:35 PM @DeltaMed910 10-Oct-20 07:36 PM Haha 10-Oct-20 07:36 PM That AGN-201 has an tube going down the center for sample irradiations 10-Oct-20 07:36 PM And it's called the glory hole 10-Oct-20 07:47 PM I mean they also have control rods that add reactivity to their core 10-Oct-20 07:51 PM Are there any other reactors that can operate with power larger than a few milliwatts and uses HDPE as the core moderator? 10-Oct-20 07:51 PM It does make a really compact core due to the high slowing down power, but it looks like neutron capture is so significant that they need these ~20% enriched fuels 10-Oct-20 07:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image-9688F.png 10-Oct-20 07:51 PM Data pulled from ENDF/B-VIII, with realistic material densities. Graphite here is nuclear grade 10-Oct-20 07:51 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image-DF6B6.png 11-Oct-20 01:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/YAP-Ce20Detector-B5B04.png 11-Oct-20 01:49 PM YAP:Ce Scintillators for Fast X-Ray Spectroscopy 11-Oct-20 01:49 PM man, that is sexy 12-Oct-20 03:03 AM Aww 12-Oct-20 03:03 AM I ordered one beautiful 30x30x30 mm CaF2:Eu cube from ost photonics 12-Oct-20 03:03 AM just 70 bucks what a bargain 12-Oct-20 03:03 AM just got an email 12-Oct-20 03:03 AM they made a mistake, original price is 700 bucks and they asked me if I want a refund or pay the rest 12-Oct-20 03:03 AM kinda not worth it 12-Oct-20 03:07 AM what a bargain! 12-Oct-20 03:07 AM compared to 700 bucks it is a bargain 12-Oct-20 03:07 AM If only ain't it 12-Oct-20 03:07 AM yep :v 12-Oct-20 03:07 AM good thing I already ordered another detector with a CaF2 scintillator 12-Oct-20 08:32 AM speaking of stuff I want 12-Oct-20 08:32 AM https://scionix.nl/wp-content/uploads/2019/02/CLLBC-datasheet.pdf 12-Oct-20 08:32 AM Oh damn that’d be cool 12-Oct-20 08:33 AM look at that resolution! 12-Oct-20 08:33 AM That’s wild 12-Oct-20 08:33 AM By the way, anyone have any ideas on what I might need to do to fix that detector of mine that’s gone weird 12-Oct-20 08:33 AM Probably just going to try replacing the connector and using a different piece of coax and keep it as short as I can 12-Oct-20 08:43 AM quick refresher on what was the problem? 12-Oct-20 09:01 AM Oh right 12-Oct-20 09:01 AM https://discord.com/channels/513115950501855256/597334400618725385/763485225215852564 12-Oct-20 09:02 AM the coax was dead, you replaced that and now it no longer ticks? 12-Oct-20 09:02 AM I assume that's the coax to the detector, right? 12-Oct-20 09:03 AM It ticks but won’t tick all the way 12-Oct-20 09:03 AM It’s an internal piece from the connector to the capacitor/hv 12-Oct-20 09:04 AM what do you mean all the way? 12-Oct-20 09:04 AM also I assume of the coax died it might have blown the capacitor / amplifier, just swap the cap and first transistor 12-Oct-20 09:04 AM Yeah, that might do it 12-Oct-20 09:04 AM All the way meaning that if I put feed in negative pulses it doesn’t respond properly and I can’t even get it to full scale 12-Oct-20 09:08 AM and how's the amplitude sensitivity? 12-Oct-20 09:09 AM Mostly unchanged but I’ll need to check again and compare it to my old notes 12-Oct-20 09:09 AM hmm ok 12-Oct-20 09:09 AM yeah, swap those two and see if that fixes it 12-Oct-20 09:10 AM Thanks, will try that 12-Oct-20 09:11 AM good luck! 12-Oct-20 03:07 PM I remember someone, maybe @GigaSquirrel posted a picture of an unrncapsulated and decently large germanium crystal a while back (maybe on Twitter?) im trying to track it down because it would be really good in a lecture I’m giving for the reactor training program 12-Oct-20 03:08 PM Aye, was me 12-Oct-20 03:08 PM was a Ge(Li) 12-Oct-20 03:08 PM you want pics? 12-Oct-20 03:08 PM Yes 12-Oct-20 03:08 PM Thank you 12-Oct-20 03:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201013_000941-36CB5.jpg 12-Oct-20 03:10 PM that's the one, I'll take better pics tomorrow, was about to go to bed right now ^^ 12-Oct-20 03:11 PM It’s okay, that works well 12-Oct-20 03:11 PM Thanks 12-Oct-20 03:11 PM I can remove the plastic shell, just tell me if you want a cleaner background or sth for scale etc 12-Oct-20 03:12 PM I’m giving the lecture this evening, now that I know it’s you it’ll be way easier to find the picture you posted before. 12-Oct-20 03:12 PM This was just a last minute addition 12-Oct-20 03:13 PM if you can't find it at all tell me, I think I can go down to the basement in the next half hour or so 12-Oct-20 03:20 PM Found it 12-Oct-20 03:30 PM Well then hereby I allow you to use my pics in a presentation 12-Oct-20 03:58 PM Thanks 12-Oct-20 03:58 PM I do suppose I should have asked first 13-Oct-20 01:08 AM I've seen my pictures of my stuff in all kinds of places 13-Oct-20 01:08 AM I don't really mind, some sources would have been nice to be mentioned, but that's the internet for 'ya 13-Oct-20 01:08 AM just wanted to explicetly state that you can use them because I know that sometimes it can cause troubles if I don't 13-Oct-20 04:10 AM https://twitter.com/GigaBecquerel/status/1315970879713619968 13-Oct-20 06:26 AM Mine should arrive today, pretty excited! 13-Oct-20 06:26 AM And I wonder how much access to the FPGA is available on a platform like this 13-Oct-20 06:26 AM All the schematic is available, and it looks like you can generate your own bitstream in Vivado and have it be compatible with the hardware on board, getting it to run well is probably going to require a lot of effort 13-Oct-20 06:29 AM fairly deep afaik 13-Oct-20 06:30 AM Did you get a quote for the CLLBC crystal? 13-Oct-20 06:30 AM I think I'm being ghosted by dynasil/RMD 13-Oct-20 06:34 AM oh, no, I didn't even ask 13-Oct-20 06:34 AM regular high rez stuff like LaBr and CeBr are ~$100 per cm³, so I bett that CLLBC will be at least 1.5 times that 13-Oct-20 06:37 AM I wanted to get a super small one and put it on a SiPM, but then the resolution would not get down to ~3.5%... Also they probably don't sell in small sample quantities unless you're a company 13-Oct-20 06:38 AM I don't exactly see the point of tiny scintillators tbh... 13-Oct-20 06:38 AM You can make the tiniest radiation everything detector that fit in the palm of your hand! 13-Oct-20 06:38 AM Get a pico power supply, use the red pitaya board, put a small touchscreen 13-Oct-20 06:39 AM I would not want to go below my 10x20 mm LaBr, the efficiency is just terrible 13-Oct-20 06:40 AM Neutron detection efficiency is pretty good actually, and you're not doing super high resolution spectroscopy with this, the red pitaya is already overkill, 1K channel is more than enough 13-Oct-20 06:40 AM and you loose all high energy efficiency 13-Oct-20 06:40 AM measurements take hours 13-Oct-20 06:40 AM if you don't want high resolution I'd go with LiI or similar 13-Oct-20 06:45 AM Well the price limits everything, bigger crystals are out of reach for mostly everyone right now for a reason. Although it would be neat to have a detector like that now, I think we'll have to wait a few years until thicker crystals come out for mounting on small special bialkali PMTs or high performance SiPMs 13-Oct-20 06:45 AM It looks like these crystals may have inherent radioactivity problems as well, in addition to the usual hygroscopic problems 13-Oct-20 06:47 AM intrinsic background is very visible in LaBr 13-Oct-20 06:47 AM cllbc will have the same issue, CeBr has almost none 13-Oct-20 06:49 AM La-138 seems to be the big problem? 13-Oct-20 06:49 AM Yep 13-Oct-20 06:49 AM I have ~2.2 cps intrinsic background in my tiny one 13-Oct-20 09:33 AM Eventually, I’d love to have my own portable home brew gamma spec setup.... 13-Oct-20 09:33 AM Red Pitaya looks awesome. 13-Oct-20 09:46 AM On the subject of scintillators... anyone have some slightly easier process ideas for making LaBr3 or CeBr3? Been looking at and planning out a couple tests with the ammonium bromide route using La or Ce oxides but that is going to be a lot of work. Especially the cerium which has to be converted from one oxide form to another before the ammonium bromide route is possible 13-Oct-20 09:46 AM The real plus of the ammonium bromide route is that it is all anhydrous so you do not have to deal with solutions but if there are easier ways I am overlooking that someone is familiar with I would love to know 13-Oct-20 10:01 AM Bridgman seems to be the go to method for small scale scintillator production 13-Oct-20 10:03 AM Yeah I am less concerned about that than the tribromides (which are prohibitively expensive to buy for an experiment on scale) so I was looking into making them 13-Oct-20 10:04 AM trichlorides also work, but with a bit less Resolution 13-Oct-20 10:09 AM That reminded me of a paper using CeCl3 for fast neutrons: https://sci-hub.st/10.1109/TNS.2010.2046911 13-Oct-20 10:09 AM Would prefer to stick to the tribromides though because the trichlorides seem to be a lot less efficient with photon production 13-Oct-20 10:16 AM fair 13-Oct-20 10:16 AM also if you want exotic high rez stuff 13-Oct-20 10:16 AM maybe try SrI:Eu? 13-Oct-20 10:24 AM I would rather not work with strontium at all heh thats one of the real bonuses for doing the lanthanum and cerium tribromides 13-Oct-20 10:24 AM La and Ce both have very little risks of bioaccumulating or toxicity... strontium not so much 13-Oct-20 10:29 AM strontium salts are toxic? 13-Oct-20 10:29 AM didn't know that 13-Oct-20 10:29 AM also also apparently mixing Cl and Br yields best results resolutionwise 13-Oct-20 10:29 AM https://www.berkeleynucleonics.com/lanthanum-bromochloride 13-Oct-20 10:29 AM pure LaBr has bad resolution below 100 keV, LBC fixes that 13-Oct-20 10:35 AM Well I am surrounded by neighbors with small kids and strontium LOVES bones 13-Oct-20 10:35 AM Basically replaces calcium biologically and can cause all kinds of issues 13-Oct-20 10:35 AM Thats why the radioisotopes of Sr are so dangerous...but the nonradioactive Sr is not great either 13-Oct-20 10:36 AM I know that it's easily built into the body, just didn't know that it causes such bad issues 13-Oct-20 10:37 AM Yeah it is not really a concern for adults afaik but I try to keep stuff I am working with nonbioactive 13-Oct-20 10:37 AM At least as far as metals go 13-Oct-20 01:07 PM So how can we make a robot that identifies ppm quantities of pollutants? 13-Oct-20 01:07 PM It seems to me like something the nuclear industry could do which would really help a lot of people. 13-Oct-20 01:11 PM the thing you're looking for is called air (activity) monitor 13-Oct-20 01:12 PM Not radioactive pollution, but things like lead, cobalt, cadmium, and ideally lower-z pollutants too but that's tougher. 13-Oct-20 01:12 PM So like for example if you have chickens how do you know if they are laying eggs that don't contain some bioaccumulative poison? 13-Oct-20 01:12 PM You can't just take them to CVS and have the 1 hour photo machine spit out numbers for you, at least, not yet. 13-Oct-20 01:14 PM an air pollution monitor? 13-Oct-20 01:15 PM Air would be nice too, cities have lots of air pollution, but solids are a good start. 13-Oct-20 01:17 PM I think the only real way to do that sort of environmental sampling requires either very long sample times or manual collection of a sample that is then processed 13-Oct-20 01:17 PM Lead contamination around battery factories shows up in the soil and on almost every surface afaik 13-Oct-20 01:18 PM Yeah I'm assuming manual sample collection like you say, where you bring the sample to the pharmacy and give them $20 for an analysis. 13-Oct-20 01:19 PM Isn't that already possible but the costs are more in the $100s range than $20? Assay labs do that for mineral samples all the time so I bet there is an environmental sample equivalent 13-Oct-20 01:19 PM Had a neighbor with a gold mine down in Mexico and the reports he was getting were incredibly detailed 13-Oct-20 01:19 PM And expensive... 13-Oct-20 01:20 PM Yup $100s is out of range of most people, but $20-$50 would be huge for accessibility and cause enough people to recognize the problem that there's pollution everywhere, that something needs to be done about it. 13-Oct-20 01:21 PM Lot of material and labor costs that would have to be worked out if you wanted to make it cheaper...and none of the analysis processes that I am aware of are particularly environmentally friendly 13-Oct-20 01:21 PM Would be nice if you could find a way but I am not sure it is a viable goal without some massive leap in disposable technology 13-Oct-20 01:22 PM I'm assuming the machine costs $10,000 and handles enough for you that some barely trained teenager can run it. 13-Oct-20 01:22 PM Maybe the sample containers are standardized, like falcon tubes. 13-Oct-20 01:23 PM the quote I just got for an OCS monitor was $125,000 13-Oct-20 01:23 PM 5 parts per trillion tho 13-Oct-20 01:24 PM PPM is probably good enough for the purpose of health monitoring. 13-Oct-20 01:26 PM Depends what you are looking for... a lot of environmental pollutants have regulatory limits in the tens of PPB don't they? 13-Oct-20 01:27 PM I mean you probably don't want to test for everything all at once like theranos tried to do, or you end up being completely unable to test for anything. 13-Oct-20 01:27 PM So whatever the most common and damaging pollutants are like heavy metals, would be a good start. 13-Oct-20 01:27 PM Yeah I am just thinking heavy metals... Arsenic was what came to mind immediately 13-Oct-20 01:27 PM Yeah Berkeley has lots of it... 13-Oct-20 01:27 PM Limits for drinking water are like 10 PPB iirc 13-Oct-20 01:28 PM My friend suggested NAA as a good methodology for this sort of testing. 13-Oct-20 01:28 PM Take a DD fusion tube and activate the sample, then gamma spec afterwards. 13-Oct-20 01:28 PM because NAA can be done out in the field and is cheap and easy... 13-Oct-20 01:28 PM ?? 13-Oct-20 01:29 PM I think parts per trillion would be more "if you're wanting to see if this is a byproduct of a reaction" type stuff 13-Oct-20 01:29 PM https://www.epa.gov/criteria-air-pollutants/naaqs-table <-- seems like a pretty wide range for the common air pollution stuff 13-Oct-20 01:29 PM @GigaSquirrel see that's the opportunity now isn't it? At one point everything cheap and easy was once expensive. 13-Oct-20 01:30 PM rofl 13-Oct-20 01:30 PM the DD tube will cost you a few 100 bucks, same goes for the power supply 13-Oct-20 01:30 PM https://www.epa.gov/wqc/national-recommended-water-quality-criteria-human-health-criteria-table <-- water chart 13-Oct-20 01:30 PM the license to spew neutrons around will cost a lot more than that 13-Oct-20 01:30 PM and then there's the detector 13-Oct-20 01:30 PM which will run you a few ten k, not including LN2 supply, and if you want ln2 ln2 free add another 5-10k 13-Oct-20 01:30 PM lead has been around for quite a while and will not get any cheaper with time, and you'll need a lot of lead for that 13-Oct-20 01:32 PM @GigaSquirrel your inner engineer is showing. Engineer's first response is to always find the problems :-) 13-Oct-20 01:32 PM Beam on target deuterium fusion tubes are not that much different from cathode ray tubes. You can put everything in a sealed box just like you do with x-ray sources so people can't hurt themselves. Making boxes that hold water isn't hard. 13-Oct-20 01:32 PM oh I'm sorry am I showing too much realism 13-Oct-20 01:33 PM No such thing as objective reality. To someone at spacex, reality is very different from a nuclear hobbyist. 13-Oct-20 01:33 PM never mind the source or shielding, that price dissapears in comparasion to a HPGe 13-Oct-20 01:34 PM So it looks like the detector is the biggest challenge then huh. 13-Oct-20 01:35 PM yes 13-Oct-20 01:35 PM Sample prep too...and disposal 13-Oct-20 01:35 PM Sample selection bias would be a bit factor in this too if the prep is not done well 13-Oct-20 01:35 PM @LRM the 1 hour photo labs had disposal problems also, you just factor it into the cost. 13-Oct-20 01:37 PM Assuming you are going the NAA route disposal for chemical wastes from photo developing and disposal of samples you are activating require entirely different levels of consideration don't they? 13-Oct-20 01:37 PM Just something to consider 13-Oct-20 01:37 PM well once you activated your sample you have to dispose of it in big yellow barrels 13-Oct-20 01:37 PM been there, done that 13-Oct-20 01:38 PM As long as it's a procedure people can follow it's not impossible. 13-Oct-20 01:38 PM oh, no, it's far from impossible 13-Oct-20 01:38 PM These places already have biomedical waste disposal. 13-Oct-20 01:38 PM it's just very, very expensive 13-Oct-20 01:38 PM The disposal costs would end up being close to the equipment costs 13-Oct-20 01:38 PM yeah but biomedical you can burn 13-Oct-20 01:39 PM So factor it in too, maybe it makes up half the cost, who knows. 13-Oct-20 01:39 PM Biomedical also uses fairly shortlived isotopes for the most part but there is no telling what you will activate in an environmental sample 13-Oct-20 01:39 PM What other techniquies besides NAA do you think are viable here? 13-Oct-20 01:40 PM mass spectrometry? 13-Oct-20 01:40 PM XRF but the same and more sample preparation concerns 13-Oct-20 01:40 PM I don't know enough about mass spec stuff to guess if you could run disposable columns for each sample or not 13-Oct-20 01:40 PM @LRM I assume you need a super bright x-ray source and monochromator to see things like PPB arsenic. 13-Oct-20 01:41 PM And extremely expensive detector 13-Oct-20 01:41 PM starting to see a pattern here 13-Oct-20 01:41 PM More expensive than SDD? 13-Oct-20 01:42 PM I am not aware of what exactly the resolution is possible with your average SDD but I would assume you need the higher end of what is available for sensing things at the level of environmental contamination/pollution 13-Oct-20 01:42 PM @GigaSquirrel I operate on the assumption money is this fake bologna that the federal reserve prints and gives to rich people to preserve the social order, it is irrelevant if you know how to pull the right strings. 13-Oct-20 01:42 PM Just look at Tesla's balance sheet if you want an example lol. 13-Oct-20 01:42 PM well then just give out samples for free 13-Oct-20 01:43 PM Money in these cases is less fiat and more time/physical/process investments required to produce the expensive equipment 13-Oct-20 01:43 PM make a company that has all the expensive machines and let people just send in samples, pay for shipping yourself 13-Oct-20 01:44 PM Anyone know a good place to source rare earth metals in metallic form? The company I had a quote from before the pandemic started does not seem to exist anymore 13-Oct-20 01:44 PM @LRM I don't understand the physics enough to comment about them, but presumably bringing a regular one down to LN2 temperature will reduce the dark current just like any other piece of silicon. 13-Oct-20 01:45 PM it's called leakage current 13-Oct-20 01:45 PM Do not think the dark current is the limiting factor as much as the resolution between the different energies too 13-Oct-20 01:46 PM Anyone know a good place to source rare earth metals in metallic form? The company I had a quote from before the pandemic started does not seem to exist anymore @LRM for low quantity stuff we have onyxmet in europe 13-Oct-20 01:46 PM @adammunich you need ln2 temps to get the leakage current low enough so that you can get your bias voltage high enough to fully deplete the crystal 13-Oct-20 01:47 PM I have given up on finding a USA based source that is a reasonable price but would rather avoid Chinese suppliers for this too...may have no choice in the end if the price differences are too drastic 13-Oct-20 01:52 PM @GigaSquirrel A stirling cryo cooler can do that 13-Oct-20 01:53 PM yes 13-Oct-20 01:53 PM but then there's the issues of microphonics 13-Oct-20 01:53 PM there are non-ln2 variants of cooling but as I said, that adds another 5 to 10 k 13-Oct-20 01:53 PM trust me, people have tried getting the price of HPGes down for decades 13-Oct-20 02:30 PM What about CdTe? 13-Oct-20 02:30 PM Amptek has some that run from TEC stacks 13-Oct-20 02:32 PM not even close to the needed resolution 13-Oct-20 02:32 PM plus they're small, so you need manymany of them 13-Oct-20 02:32 PM ideally you'd want with pgaa, not naa, as it's way more versatile 13-Oct-20 02:32 PM but that's easily in the >5 MeV range, and you need huge crystals for that 13-Oct-20 02:41 PM I think even NISTs PGAA system is only good down to the ppm level for the vast majority of elements... This shows it can detect 1-10ug of stuff like As in a 1gram sample (1-10ppm) but a much narrower range of things it can sense below that: https://www.nist.gov/laboratories/tools-instruments/prompt-gamma-ray-activation-analysis-pgaa 13-Oct-20 02:42 PM 35% HPGe in lots of lead surrounded by a compton suppressor 13-Oct-20 02:42 PM well 13-Oct-20 02:42 PM haha neat 13-Oct-20 02:42 PM they're doing that here with 10^14 n/s*cm² 13-Oct-20 02:44 PM Noob question, why do we use germanium instead of Si? 13-Oct-20 02:45 PM Density 13-Oct-20 02:46 PM But a large boule of silicon isn't that expensive anymore 13-Oct-20 02:47 PM it still is at the kind of purity you need for this 13-Oct-20 02:47 PM the HP in HPGe stands for high purity 13-Oct-20 02:47 PM high being 12 to 15 nines after the comma 13-Oct-20 02:47 PM at that point the refining is the expensive part and it doesn't matter if you use Si or Ge 13-Oct-20 02:47 PM smaller stuff works at lower bias voltages where leakage current isn't much of an issue and it doesn't need much stopping power, that's why SDDs are SDDs and not GeDDs 13-Oct-20 02:49 PM Seems like we would need to take a step back and rethink detectors entirely 13-Oct-20 02:50 PM I wish you the best of luck with that. 13-Oct-20 02:52 PM Same, totally seriously... It would be nice to do away with the need for the super high purity single crystal detectors...but I doubt that is going to be possible without some equally complex/resource intensive option 13-Oct-20 02:53 PM Well so basically what we need is something with uniform stopping power and a way to detect where the particle comes to rest, right? 13-Oct-20 02:54 PM Assuming you can somehow limit all activity in the "something" to a single uniform direction and a bunch of other caveats that would appear with more time thinking on it than I have to spare at the moment 13-Oct-20 02:56 PM We need something that takes high energy phtons and converts them to something we can easily detect, either low energy photons or charge 13-Oct-20 02:56 PM What is the purpose of the ultra high purity requirements in a crystal detector? 13-Oct-20 02:56 PM getting leakage current down 13-Oct-20 02:57 PM Ah ok removing stray charge carriers 13-Oct-20 02:57 PM In the scintillators you need high purity to keep your low energy photons from being absorbed before they are reflected into the PMT/detector 13-Oct-20 02:58 PM Ok here is my immediate wacky idea . Structured light. Take hundreds of layers of scintillation material and view them edge-on with a camera. The relative penetration of the particles thorough the layers will tell you the energy. 13-Oct-20 02:59 PM you're assuming there's no scattering, no secondary particles are produced, no paar production happens 13-Oct-20 02:59 PM no x-ray fluorescense in the detector 13-Oct-20 02:59 PM nothing 13-Oct-20 02:59 PM Shielding concerns alone make that nonviable imo 13-Oct-20 02:59 PM All the activity would have to come from a single direction or your measurements will have no value 13-Oct-20 03:00 PM Wdym? Imagine you have a plastic scintillator sheet, and you vapor deposit some high Z on it, then roll it up like a jelly roll and look at it edge-on. 13-Oct-20 03:00 PM The relative brightness across the thickness will represent energy vs count rate at that energy 13-Oct-20 03:01 PM no it won't 13-Oct-20 03:01 PM photons get scattered 13-Oct-20 03:01 PM your material will fluoress 13-Oct-20 03:01 PM with the energies we're talking about secondary particles will be produced 13-Oct-20 03:01 PM which will all fly in random directions 13-Oct-20 03:02 PM So you want to supress that effect also then 13-Oct-20 03:02 PM which you can't 14-Oct-20 02:29 PM https://twitter.com/GrantWTrent/status/1316486151327408144 Spectroscopic TV! 14-Oct-20 02:29 PM back when there still was good stuff on... 14-Oct-20 02:52 PM Grant likes bringing nice things from the archives. 14-Oct-20 02:56 PM oh yes 14-Oct-20 02:56 PM too bad that often there's not much info on them 14-Oct-20 02:56 PM http://www.iki.kfki.hu/about_us/archive/photos_hu.shtml That's where the pics are from 14-Oct-20 02:56 PM man that looks nice 15-Oct-20 02:03 AM PGAA seems like a viable and safer alternative to DNAA for pollutant detection. 15-Oct-20 02:03 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Sensitivity-of-PGAA-for-the-elements-9-Sho-E2843.png 15-Oct-20 03:42 AM safer how? 15-Oct-20 07:47 AM Part of the issue is complexity and sample throughput id imagine 15-Oct-20 07:47 AM And ease of frying your detector 15-Oct-20 07:47 AM Unrelated, why have I never seen amateur liquid scintillation counting 15-Oct-20 08:38 AM the fluors seem kinda yucky 15-Oct-20 08:38 AM idk if those are DIYable, that seems the hard part really 15-Oct-20 09:05 AM I know there’s at least one that’s sold by a company that sells to individuals but it is an older psuedocumene based cocktail 15-Oct-20 09:16 AM Also the calibration counting vials and internal source of the LSC unit. There is comparatively less toxic cocktail which you can get, but none of it is really go down the drain safe. That said, tinkering to create your own quench curves is becoming a lost art. 15-Oct-20 09:37 AM Yeah I suppose a carbon 14 source/tritium source is going to be a bit of a pain to come by 15-Oct-20 09:38 AM Just make your own from those little H3 lights 15-Oct-20 09:38 AM Sorry, I had to 15-Oct-20 09:38 AM please don't do this 15-Oct-20 10:49 AM safer how? @GigaSquirrel from what I have been reading you can frequently get a sample identified fast enough that residual activation is not significant and you don't end up with something radioactive afterwards. 15-Oct-20 10:49 AM Or at most, negligibly radioactive. 15-Oct-20 10:51 AM well you still have to capture neutrons 15-Oct-20 10:51 AM transmuting your stuff 15-Oct-20 10:51 AM which results in radionuclides 90% of the time 15-Oct-20 10:54 AM Yeah but the required quantity/activity of long lived radionuclides is lower than delayed activation techniques. So PGAA is the preferred NDT method when the sample must be returned to its original situation instead of destroyed. 15-Oct-20 10:55 AM there is no prompt or delayed activation 15-Oct-20 10:55 AM (these terms are according to the NIST literature) 15-Oct-20 10:55 AM it's called prompt because you look at the prompt gammas that are a result of the capture reaction 15-Oct-20 10:56 AM Prompt = look at it during irradiation Delayed = look at it afterwards 15-Oct-20 10:56 AM prompt = look at the prompt gammas 15-Oct-20 10:57 AM If you look at the sample /while/ it's being irradiated you can get meaningful data with much less neutron activation according to what I've been reading. 15-Oct-20 10:59 AM but you also need way higher flux 15-Oct-20 11:00 AM What sort of pollution are you hoping this would be able to look for? Water? Air? Soil? Because that chart is for a 1 gram sample afaik and if you are testing water or air I am not sure you will be getting enough resolution to really even monitor things for the EPA limits in water for arsenic...the air sampling I am less clear on how exactly the sample size calculations work for pollution limits 15-Oct-20 11:01 AM 10^12 and 10^13 Bq are numbers I've seen thrown around which is just about at the upper limit of what a D-D ion beam thing can get you. 15-Oct-20 11:01 AM @LRM Soil to start with 15-Oct-20 11:03 AM Soil has a lot more disposal concerns because of the whole activation part of PGAA or NAA :/ but good luck 15-Oct-20 11:04 AM PGAA here is done with 10^14 nv thermal 15-Oct-20 01:28 PM And while there are some very nice D-D generators out there, getting to the 10^12 n/s flux remains QUITE aspirational. 15-Oct-20 01:28 PM This is also what NAA of any kind is generally regarded as destructive testing. 15-Oct-20 04:32 PM https://www.youtube.com/watch?v=H1ckdTlgvlU 15-Oct-20 04:32 PM Lots of interesting footage in this and some nice demonstrations for explaining basic concepts to people. 15-Oct-20 04:32 PM Gonna have to reuse the golf ball putting analogy about fast vs slow neutrons 15-Oct-20 08:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/download-053CF.webp 15-Oct-20 08:17 PM What ever became of the sandia labs neutristor? Haven't heard anything about it in a decade. 15-Oct-20 08:39 PM My understanding of that is they do not produce enough neutrons to do a whole lot with so far 15-Oct-20 08:39 PM Also they have to be pulsed 15-Oct-20 08:40 PM Yeah I wouldn't have expected much from a field emission tube 15-Oct-20 08:40 PM Looking them up really quick it seems like they do around 1000 neutrons per 500ns pulse? 15-Oct-20 08:40 PM https://arxiv.org/ftp/arxiv/papers/1308/1308.0327.pdf 15-Oct-20 08:43 PM Yeah I don't know what you would do with that 15-Oct-20 11:25 PM They are looking to use a 1e9 n/s D-T tube to detect explosives underground, but factors like soil moisture, density and low detector efficiency for a compact size makes that really difficult 15-Oct-20 11:25 PM Californium isn't really an option for these types of applications since no amount of physical shielding would be acceptable near IEDs, also it would just be very heavy with shielding 15-Oct-20 11:25 PM I think the pyroelectric neutron sources have demonstrated much better success than the neuristor on a similar sort of scale 15-Oct-20 11:25 PM But yeah still well below 1e5 n/s, and it can't be run at 100% duty cycle since it relies on a temperature change 15-Oct-20 11:31 PM Wonder if triboelectricity would work better like that defunct x-ray startup had tried 15-Oct-20 11:31 PM Doesn't it only produce x-rays? 15-Oct-20 11:31 PM They basically took some adhesive and glued it to a vibrating reed 15-Oct-20 11:32 PM You can't ionize and accelerate deuterons with it right? 15-Oct-20 11:32 PM @Mason_Yu it makes electric field which then produces xrays so presumably a neutron source could work too 15-Oct-20 11:36 PM As far as I can see in the papers that describes the generator, the adhesives are only providing a source of high energy electrons due to the difference in triboelectric potential 15-Oct-20 11:36 PM Which is not exactly the same as a strong localized electric field with a large gradient and potential difference > 30kV 15-Oct-20 11:36 PM Those electrons would be much more efficient charge carriers than any ions 15-Oct-20 11:36 PM And since the two material are in contact, those electrons would quickly transfer between the two and very little acceleration on the ions could be generated 15-Oct-20 11:40 PM So you suspect that field emission of the electrons would carry away so much charge that no ions move 15-Oct-20 11:40 PM I could believe that 15-Oct-20 11:41 PM It's not exactly field emission either though is it? It's just a difference in local electron density essentially 15-Oct-20 11:41 PM *free electron density 15-Oct-20 11:43 PM Now you have me thinking about wacky ideas like kelvin droplet generators in a vacuum 15-Oct-20 11:44 PM how would that work 15-Oct-20 11:45 PM https://en.m.wikipedia.org/wiki/Kelvin_water_dropper Same way it always would but in a low pressure neon environment you might get a nice light show 15-Oct-20 11:45 PM I know how the generator works, but liquid drops and vacuum don't exactly work well together 15-Oct-20 11:46 PM I've seen a video long ago that showed mercury splashing in a low pressure environment, makes enough triboelectricity to ionize the fill gas. 15-Oct-20 11:46 PM dunno what happened to the video but here is the sample https://theodoregray.com/periodictable/Samples/080.9/index.s15.html 15-Oct-20 11:55 PM I'm sure that that'd work and give a nice lightshow, but I don't see any practical applications in it 15-Oct-20 11:56 PM sometimes the neatest discoveries are made by accident 15-Oct-20 11:56 PM sure, sometimes they are 15-Oct-20 11:56 PM i like trying odd things 15-Oct-20 11:57 PM but the quota is terrible 16-Oct-20 03:39 PM I know how the generator works, but liquid drops and vacuum don't exactly work well together @GigaSquirrel Depending on the desired pressure many liquids may have a suitable vapor pressure. Petroleum raffinates go rather far and one may have a bit left after a rotary vane's oil change Mercury and GalInStan have a very low vapor pressure and some ionic liquids do too 16-Oct-20 04:56 PM @adammunich thats my way of doing things lol 17-Oct-20 03:32 AM https://www.reddit.com/r/chernobyl/comments/e4ldxu/latest_work_of_illegal_stalkers_from_the_abo_group/ I cannot express enough hatred towards these people 17-Oct-20 03:32 AM At least now it fits the theme 17-Oct-20 03:32 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1t612z84jbi41-6E161.png 17-Oct-20 04:48 AM what the heck 17-Oct-20 06:37 AM aaaaaa 17-Oct-20 08:50 AM The swear filter is not letting me express my full feelings on this matter. 17-Oct-20 09:44 AM I was not enlightened 17-Oct-20 09:44 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screen_Shot_2020-10-17_at_9.42.00_AM-2A74D.png 17-Oct-20 10:10 AM https://www.youtube.com/watch?v=C9npqRJ_9P8 17-Oct-20 10:18 AM Sad they vandalized/destroyed that piece of history...and probably gave themselves a decent amount of contamination in the process 17-Oct-20 10:18 AM https://www.youtube.com/watch?v=clN1p4dtm2E 17-Oct-20 10:18 AM Wonder how much nasty crap the spray paint put up in the air 17-Oct-20 10:21 AM oh 17-Oct-20 10:21 AM @LRM now someone painted it yellow-gold... 17-Oct-20 10:21 AM https://www.youtube.com/watch?v=w2YjpC4kJfE 17-Oct-20 10:21 AM ;>_> 17-Oct-20 10:23 AM I love how they don't have any PPE at all 17-Oct-20 10:24 AM check out bionerd23 17-Oct-20 10:24 AM she doesn't seem too concerned 17-Oct-20 10:27 AM must... not.... hurt... people 17-Oct-20 10:27 AM she doesn't seem too concerned @sushi while she's taking more risks that I'd recommend she knows what she's doing. You don't need to be too concerned if you just know where to stand and what (not) to touch 17-Oct-20 10:29 AM wonder where she tossed the radioactive napkin (she wiped the inside of the claw and measured it then paper disappeared off camera) 17-Oct-20 10:31 AM From what I've seen bionerd23 actually knows her stuff quite well and generally they do wear ppe when appropriate in her videos 17-Oct-20 10:31 AM She also has a lot of university/academic connections which I am sure helps with waste disposal from things like that 17-Oct-20 10:32 AM She also has a lot of university/academic connections which I am sure helps with waste disposal from things like that @LRM she does? 17-Oct-20 10:32 AM That was my impression...? I have only ever talked to her briefly online 17-Oct-20 10:33 AM >disposal put it in your radioactive collection cabinet at home 17-Oct-20 10:33 AM "claw dust" 17-Oct-20 10:33 AM I know that eg. her measurement stuff is done by a hobbyist 17-Oct-20 10:33 AM the alpha and gamma spec 17-Oct-20 10:36 AM Hmm...thought I was facebook friends with her but the account is disabled now 17-Oct-20 10:36 AM Oh well 17-Oct-20 10:38 AM I'm good friends with her measurement guy but have never actually talked to her directly 17-Oct-20 10:40 AM shes secretive uwu 17-Oct-20 10:40 AM is this the channel for ionized gas posting? 17-Oct-20 10:48 AM post whetever you feel is appropriate ^^ 17-Oct-20 10:48 AM #general is appropriate for pretty much anything remotely related to vacuum stuff 17-Oct-20 10:48 AM is vacuum? yes. Has vacuum? yes. could be used with vacuum? yes. 17-Oct-20 11:32 AM I mean you can't really expect any different from a country with minimal economic activity. 17-Oct-20 11:32 AM People are bored and when they're bored they do silly things. 17-Oct-20 11:32 AM I bet you the pink taggers are gonna be annoyed that their work got buffed and will spray over the gold team fairly soon. 17-Oct-20 11:40 AM There is a culture of incredible stupidity that goes on in the exclusion zone so I do not think it is so easy to brush off as just bored people doing "silly things". Could be but my feelings are that this is not just that 17-Oct-20 11:47 AM This to me just seems like your average graffiti war. Perhaps eventually the whole claw will become so encased with paint it becomes safer. 17-Oct-20 11:47 AM I saw kreyosan went to work refurbishing one of the apartment flats in the exclusion zone, they did a pretty good job but I think they got discouraged after some vandalism ruined it. 17-Oct-20 11:55 AM For redacted sake what 17-Oct-20 11:59 AM kreosan did WHAT? XD 17-Oct-20 11:59 AM Can you really blame them? Local wage in Ukraine is so low, but meanwhile some folks in mountain view will pay you 10x that number to get some halff-baked carpentry work done in an abandoned flat for the ad clicks. A lot of people in their shoes would have done the same. 17-Oct-20 12:01 PM I mean, a fair part of it’s the contamination concern now 17-Oct-20 12:02 PM They also have a project to get the ferris wheel running again I am not sure what the latest news is on that. 17-Oct-20 12:04 PM I think we have a fundamental disagreement about the nature of what kreosan et al are up to 17-Oct-20 12:05 PM Oh I agree with you it's reckless but what I'm saying is you need to understand where they're coming from. It's really easy to live in a developed country and point fingers but for these people it's like, the best economic opportunity around. 17-Oct-20 12:06 PM I understand "where they're coming from" and it transcends stupidity and into reckless disregard for themselves, others, the environment, and history fairly often in what I have seen 17-Oct-20 12:08 PM To me this problem pales in comparison to what's going on right now in Agbogbloshie. 17-Oct-20 12:08 PM That's a situation that needs to be unf_cked yesterday. 17-Oct-20 12:10 PM Just because one thing is worse does not make this other thing happening in a literal "exclusion zone" set up for very good reasons (that last thousands of years) okay or any less bad. 17-Oct-20 12:10 PM Anyway, it is okay to disagree on this and I do not think either of us are going to convince each other either way 17-Oct-20 12:11 PM Correct, but for any change to happen you need to set the incentives for the local people in a productive direction. Otherwise they just ignore you, or at worst, do more of it out of spite. 17-Oct-20 12:11 PM Like if you really wanted to stop kreyosan's shenanigans here, buy them some equipment and give them a contract to develop a radio repeater or something for sensor networks. Then they won't need to screw around in the exclusion zone for ad $. 17-Oct-20 12:14 PM https://www.youtube.com/watch?v=shV2qoZShV0 17-Oct-20 12:14 PM ^^^ 17-Oct-20 12:15 PM You might enjoy the videos where they take some magnetrons and make them into electromagnetic rifles 17-Oct-20 12:18 PM lol in this video they're worried their xrays may have induced radioactivity in their hand ... you'd ... need uh about 2MeV photons for deuterium or 10MeV> higher for other heavier nuclei... 17-Oct-20 12:21 PM If you followed their videos over the years it becomes clearly obvious that doing this wacky stuff on YouTube has greatly improved their economic situation. These guys used to live in a building that didn't even have a roof or windows that worked properly. 17-Oct-20 12:21 PM In that x-ray gun video, now they have this really nice wood panel laboratory situation with tons of equipment and like, a roof that doesn't leak. 17-Oct-20 12:21 PM Every so often though you still hear a bomb fall and explode, in the background of their videos. 17-Oct-20 12:43 PM @sushi That one is actually pretty terrifying. I hope they get smarter about shielding that x-ray tube. 17-Oct-20 12:47 PM yeah 17-Oct-20 12:47 PM i'd like to know what their accel voltage and tube current was 17-Oct-20 01:06 PM I've run a lot of those tubes, looks to me like 60kV and 2-3mA 17-Oct-20 01:06 PM The tubes without Be windows usually don't start emitting anything until 40kV. 17-Oct-20 01:06 PM Ground glass ones, maybe can get down to 30kV. 17-Oct-20 01:06 PM Uranium ore and fusors are fun and all, but those coolidge tubes can really f you up if you're not careful. A few cm from the aperture, you may measure dose rates as high or higher than 1 Sv / minute. 17-Oct-20 01:06 PM Be window tubes, they are a whole different kind of scary. Try 10+ Sv/min on for size. 17-Oct-20 04:22 PM Their recklessness inspires others. And that's the real problem 17-Oct-20 05:22 PM I know bionerd23. I've done three zone trips with her, and she's visited us in Chicago. 17-Oct-20 05:22 PM She knows her stuff. 17-Oct-20 05:22 PM The statements about the claw being ridiculously dangerous and one touch would kill are complete rubbish. 17-Oct-20 05:22 PM I've visited the claw on two separate occasions. 17-Oct-20 05:24 PM would like to hear what happened to the two women sitting in it earlier 17-Oct-20 05:25 PM It is one of the hotter accessible items. But as long as you don't touch the parts with mobile contamination, you are safe. 17-Oct-20 05:25 PM I want to know what happened to the women sitting in the claw. My guess is they probably lit up the portal monitors and contaminated the floor and possibly seats of their tour vehicle. 17-Oct-20 05:25 PM I am effing furious that anyone would spray paint it. 17-Oct-20 05:36 PM Their recklessness inspires others. And that's the real problem @rfs it's true but "let them eat cake" sort of policies isn't going to help. What will help is increasing the opportunity that these people have to work on more productive things 17-Oct-20 05:37 PM Sure. 17-Oct-20 06:24 PM I have an... interesting view about the Zone that I don’t think everyone will agree with. 17-Oct-20 06:24 PM I view it not as a time capsule, or museum, but as a living, evolving thing. 17-Oct-20 06:24 PM So, changing things in it can be positive, and it can be negative. 17-Oct-20 06:24 PM It’s just like the rest of the world. 17-Oct-20 06:24 PM I’ve seen artists make changes to the Zone that I approve of. 17-Oct-20 06:24 PM Some people repainted the faded Soviet hammer and sickle sign on top of a building. That’s cool. 17-Oct-20 06:24 PM But spray painting the claw pink like that? That’s just vandalism. No. 17-Oct-20 06:24 PM I’m mixed in my view of Kreosan. 17-Oct-20 06:24 PM On one hand, I see fixing up the flat as, generally, cool. 17-Oct-20 06:24 PM On the other hand, he’s publicizing too much. Bringing too much of the wrong kind of attention that is going to cause problems. 17-Oct-20 06:24 PM Like the Ferris wheel. 17-Oct-20 06:24 PM The Zone administration is really reactionary. 17-Oct-20 06:24 PM They don’t do stuff until someone forces their hand. And the consequences are then bad. 17-Oct-20 06:24 PM Like Bionerd’s judgment lapse in taking bicycles into the basement of the hospital along with an infamous street cyclist, riding around down there, and posting it online where it went viral. 17-Oct-20 06:24 PM There’s been plenty of hospital basement footage online. I’ve been in the hospital basement. 17-Oct-20 06:24 PM But the bicycles were too much. Too much risk of kicking up contamination. 17-Oct-20 06:24 PM After that went viral, the Zone administration drove a dump truck through the hospital door and buried the main stairwell. 17-Oct-20 06:24 PM This doesn’t stop people from going down there, but it makes it harder and sends a message to the Zone guides who run private tours that maybe they should consider it off limits. 17-Oct-20 06:24 PM Likewise, Duga. 17-Oct-20 06:24 PM Some poor stalker got himself killed climbing it in the night in winter. 17-Oct-20 06:24 PM So they chopped off the ladders up to a height of about 10 meters. 17-Oct-20 06:24 PM I’m glad I got a chance to climb it before that happened. Now, it’s still possible, but it requires free climbing the first 10 meters or so, which puts it out of the athletic range of a lot of people, and sends a message to the private tour operators that it’s no longer a “we’ll look the other way” place. 17-Oct-20 06:24 PM To that end, I’m effing terrified of what Kreosan is doing to the Ferris wheel. 17-Oct-20 06:24 PM There have been at least two videos of people moving it. 17-Oct-20 06:24 PM Kreosan wants to motorize the thing again. 17-Oct-20 06:24 PM This could easily get the Zone administration’s attention, cause them to declare it too dangerous and dismantle it. 17-Oct-20 06:24 PM Kreosan is also exposing way too much stalker tradecraft. 17-Oct-20 06:55 PM Yeah 17-Oct-20 06:55 PM Also, I'm sad to hear that the ladders have been chopped. And so high too 17-Oct-20 06:55 PM I was hoping to one day climb to the middle of it, hook up a radio via a balun to the existing ladderline feeds and seeing how it would work for some 3.5MHz or 7MHz amateur operating. 17-Oct-20 07:07 PM Turn the Russian woodpecker on again... 17-Oct-20 07:11 PM all the hams are going to get angry lol 17-Oct-20 07:16 PM I’m more thinking about the OMs who recognize it and then fall out of their chairs 17-Oct-20 07:19 PM It should go without saying that if there's someone I have a dimmer view of than styro, it's kreosan. Bionerd, less so but in the ballpark. The Japanese authorities working on the Fkushima Hard-To-Return-To Area pay attention to all of this and look at it with absolute horror. Not just for the contamination control issues but the thing that that strikes home for them is the *disrespect. Preventing the stalker culture from spreading to Japan is one of their high priorities. They've done their best and are quite clear that they blame Americans for treating their tragedy like a playground. 17-Oct-20 07:38 PM @rfs I overestimated the distance. The ladders appear chopped to the first level. There are 20 levels with antennae and there appear to be the distance of two more to get to the top. So 150 m / 22 is about 6.8 m. 17-Oct-20 07:38 PM Still a very bad drop 17-Oct-20 07:40 PM “Shiey” (who also is exposing way too much stalker tradecraft) did a YouTube video of a Duga climb after the ladders were removed. 17-Oct-20 07:40 PM https://youtu.be/AlAS_Ecmx_0 17-Oct-20 07:40 PM Now I believe he free climbs onto and inside of one of the antenna elements. That’s just... insane.... 17-Oct-20 07:40 PM Now I remember, that is why I’m unhappy with him.... It’s the kind of thing that is too extreme and goes viral. 17-Oct-20 07:50 PM Yep 17-Oct-20 07:50 PM Leave nothing but footprints. Take nothing but photographs. Be sure to survey out. 17-Oct-20 07:51 PM And be careful where you post the damn photos... 17-Oct-20 07:59 PM OPSEC is important in all walks of life. 17-Oct-20 08:01 PM Exactly.... 17-Oct-20 08:02 PM also, i'm just going to laugh a bit at what the profanity filter decided to get rid of earlier 17-Oct-20 08:02 PM Oh, the name of the location in Japan where there was a nuclear meltdown? 17-Oct-20 08:05 PM yes 17-Oct-20 08:05 PM f​ukushima (threw a zero width joiner in there) 17-Oct-20 08:06 PM I remember having a problem with a former employer’s email server discussing condiments for hot dogs and bratwurst. It didn’t like the word sauerkraut. 17-Oct-20 08:07 PM ouch 17-Oct-20 08:07 PM I also had a problem with a twitter content monitor thinking I was saying something obscene when I was talking about soldering. It didn’t like the acronym SMD. 17-Oct-20 08:08 PM amazing 17-Oct-20 08:08 PM that's hilarious 17-Oct-20 08:09 PM Also, Bionerd likes to make her videos look more edgy and provocative, when she generally is fairly conservative around the risks she takes. 17-Oct-20 08:09 PM A lot of people think she recklessly had herself injected with Tc-99m when it was for a necessary medical procedure. 17-Oct-20 08:09 PM People see her dig around in dirt for hot particles with her bare hands. And... off camera, there’s scrubbing with bottled water and surveying. Quite a lot of surveying for everybody prior to getting back into the vehicle. 17-Oct-20 08:13 PM how would you even get Tc-99m as an individual? 17-Oct-20 08:20 PM She did a video a number of years ago where she dipped her fingers in Tc-99m solution, tried various decon methods, and surveyed the results. I believe she had an academic connection to a medical institution to get that. All things considered, the videos have a high “squick factor” designed to get attention, but the total dose is utterly negligible compared to what one gets when that stuff is injected for a procedure. 17-Oct-20 08:20 PM She actually pulled back the curtain on herself when she ate the Chernobyl apple, but most people glossed over that part. HPGe showed 40 Bq/kg which is a small fraction of what the Eu considers safe for food. And, it’s not like her diet consists of those apples exclusively. 17-Oct-20 08:20 PM That’s the problem with understanding dosimetry, you get into arguments with people who don’t. I really got into it with a UChicago prof running an event around F*kushima. The scientists in a documentary video puréed some fish, showed a scint registering gamma counts that was supposed to be positively terrifying to the viewers, but I caught the Bq/kg result and protested that this fish would be legal to sell as food. 17-Oct-20 08:35 PM Yeahhhhh, while linear no threshold might make regulatory sense it does terrible things to public perception 17-Oct-20 08:37 PM F*kushima sushi +️ 17-Oct-20 08:39 PM yes 17-Oct-20 08:39 PM wait what? 17-Oct-20 08:39 PM oh i thought someone called me 17-Oct-20 08:39 PM lol 17-Oct-20 08:41 PM I remember trying to persuade someone that radiation wasn’t that bad as it’s already around us, and it backfired. I then had to talk him out of pulling all the smoke detectors out of his home. 17-Oct-20 08:41 PM everything and everyone is radioactive 17-Oct-20 08:41 PM lol @ the smoke detectors 17-Oct-20 08:41 PM dad's the same way 17-Oct-20 08:41 PM he thinks he's gonna get cancer from sitting next to a 1uCi Am241 source 17-Oct-20 08:43 PM well he will 17-Oct-20 08:43 PM we all will 17-Oct-20 08:43 PM The irony is that the guy had a red granite dining room table. Absolutely beautiful. 17-Oct-20 08:43 PM sure theres some gamma from it but it isn't that hot 17-Oct-20 08:43 PM xD 17-Oct-20 08:43 PM that's sort of how cancer works 17-Oct-20 08:47 PM I whacked my CDV-700 w/ pancake on the door on the way in. I was worried about it. Set it down on the table. Turned it on. It was reading about 2x background. That spooked me, as I thought I damaged something, but my mental troubleshooting was coming up short about what could be wrong with it. That’s when I noticed the table was red granite. 17-Oct-20 08:47 PM Later, I demonstrated the activity of his table. He turned pale. Like, seriously freaked, and was worried that his kids ate breakfast at it. He seriously wanted to get rid of it. 17-Oct-20 09:00 PM @idmb hmm? 17-Oct-20 09:00 PM @rdpierce too bad bananas don't really show up to a GM too well 17-Oct-20 09:00 PM "time to stop eating potassium" 17-Oct-20 09:00 PM xD 17-Oct-20 09:02 PM You’re retracing the conversation..... 17-Oct-20 09:02 PM I was giving an impromptu Chernobyl tourism talk at his house for some mutual friends. 17-Oct-20 09:02 PM i am? im distracted, sorry 17-Oct-20 09:03 PM (No, you’re retracing the way my conversation with him went..... Nothing wrong!) 17-Oct-20 09:03 PM He basically told me I was insane for wanting to be around anything radioactive. So I showed him that his table was radioactive. 17-Oct-20 09:03 PM I then had to convince him not to discard it. 17-Oct-20 09:05 PM sounds like a nice way to get a table 17-Oct-20 09:05 PM but also, damn 17-Oct-20 09:05 PM I told him bananas were radioactive and his response was that he knew there was a reason he didn’t like bananas. 17-Oct-20 09:05 PM I told him that his smoke detector was radioactive and he said he’d remove them all and I really had to argue with him. 17-Oct-20 09:06 PM I'm happy? that I haven't ever run into anyone like that so far 17-Oct-20 09:07 PM ive run into some people who think RF is the same as ionizing radiation 17-Oct-20 09:08 PM @Addison-110m yeah, that was a very nice table, the thought did cross my mind. 17-Oct-20 09:08 PM i spent about 4 hours explaining to him and his wife and kids about the electromagnetic spectrum 17-Oct-20 09:08 PM ive run into some people who think RF is the same as ionizing radiation @sushi OMG 5G causes cancer aaaaahhhhh 17-Oct-20 09:09 PM This...this is unfortunately part of my job. In Berkeley. [pours fresh cocktail] 17-Oct-20 09:09 PM unfortunately, we had an incident where someone called the regulatory bodies against a ham radio operator 17-Oct-20 09:09 PM his wife and kids understood me and were like "waow i wanna be like him when i grow up" he was sorta like deflated but still somewhat sutbborn "uhm... well okay i think you know what you're talking about but I still want to believe microwaves are dangerous" 17-Oct-20 09:09 PM because "aahhhhhh radiation" 17-Oct-20 09:10 PM then i told him "uh they are dangerous... but just not in the way you're thinking" then i went on a lecture about high power RF safety and what types of damage it could do and what plasma is and what RF is 17-Oct-20 09:10 PM then he seemed less confused and a little happy 17-Oct-20 09:10 PM @SleepyOwl Joyce yeah exactly 17-Oct-20 09:12 PM I spend an inordinate amount of time teaching people, staff and members of the public, the differences between radiation (ionizing vs. non), radioactive materials, activation, and contamination. 17-Oct-20 09:12 PM It DOES NOT HELP that I am fighting against certain members of faculty committed to pseudoscience. 17-Oct-20 09:13 PM Pseudoscience? 17-Oct-20 09:13 PM Having to convince someone that 0.8 uCi Am-241 outside their bedroom door is preferable to, oh, DYING in a FIRE was not fun. I don’t want it on my conscience if he actually ripped out his smoke detectors. 17-Oct-20 09:13 PM Hormesis or something else 17-Oct-20 09:13 PM y'know a good analogy to "aaaah radiation"? "radiation" is like saying "vehicle" instead of specifying "car" or "plane" or "train" a car can probably stop before it kills you a train wont and will probably kill you 17-Oct-20 09:13 PM the best part in that incident is that the National Environment Agency here actually brought radiation meters and things like that to the location 17-Oct-20 09:14 PM Hormesis is a nice starting point but also very committed to “wifi eats babies”. 17-Oct-20 09:14 PM (then explain the car is non ionizing and the train is ionizing) 17-Oct-20 09:14 PM Oh. Berkeley has faculty like that too? I thought it was confined to UChicago. 17-Oct-20 09:14 PM I’ll take hormesis over babies, 1 might have a little bit of data behind it 17-Oct-20 09:15 PM Oh goodness no. A certain public health professor is responsible for the particularly dodgy WHO paper on 5G. 17-Oct-20 09:15 PM wait who 17-Oct-20 09:15 PM i don't know this paper 17-Oct-20 09:16 PM Oh goodness no. A certain public health professor is responsible for the particularly dodgy WHO paper on 5G. @funranium wth? 17-Oct-20 09:17 PM Where if you read enough of these reports you can see the desire of the committee to not issue this but, well, it is true we can’t definitely say $THING doesn’t cause cancer. Proving negatives is hard and the worst argument position. 17-Oct-20 09:19 PM Yeah @Addison-110m it’s my impression that it’s so hard to get data about biological effects of low doses that hormesis can’t be differentiated from LNT. 17-Oct-20 09:19 PM Oh that's entirely the case 17-Oct-20 09:19 PM This one. https://www.iarc.fr/wp-content/uploads/2018/07/pr208_E.pdf 17-Oct-20 09:20 PM When I say "little bit" I mean some interesting animal studies I recall seeing. nowhere near enough to say things about humans 17-Oct-20 09:21 PM It is remarkable how much BS on Whole Foods bulletin boards points back to this document. 17-Oct-20 09:22 PM There’s some stuff about a Taiwanese apartment building made from recycled “lost source” steel. And a study about nuclear vs. non-nuclear Navy ship welders. 17-Oct-20 09:22 PM https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477708/ 17-Oct-20 09:25 PM oh great 17-Oct-20 09:25 PM rf "possibly" carcinogenic to humans 17-Oct-20 09:25 PM |: 17-Oct-20 09:25 PM is this like how Disney is known to the State of California to cause cancer? :^) 17-Oct-20 09:25 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/CAlifornia-Prop-65-sign-CCAE2.png 17-Oct-20 09:26 PM To be clear, I don’t believe in hormesis, but I also think it’s bad science to draw a straight line back to the origin and say that has to be true without the data to back it up. 17-Oct-20 09:27 PM don't worry the sign causes cancer too 17-Oct-20 09:27 PM DO NOT lick things at Disney. 17-Oct-20 09:27 PM @rdpierce agreed 17-Oct-20 09:27 PM hey can i have a bigger version of your profilepic funranium? 17-Oct-20 09:29 PM Nope 17-Oct-20 09:29 PM Filling in that gap down to the origin has been the work of 80 years of health physicists. What started as a legal argument is holding up quite nicely. Personally, I wouldn't be surprised if there is threshold but every time we think we've fond it, we push it a little further down the line. 17-Oct-20 09:31 PM I got into an argument recently with someone that said a friend got cancer from Chernobyl when they just happened to be in Europe some distance away at the time. Ehhh.... just being human gives you a 40% chance of getting cancer and 20% chance of dying of it. Causality doesn’t work like that. 17-Oct-20 09:34 PM Yeah there’s always the fun reactor training slide of no, reactor training won’t give you cancer but you probably will get it anyway 17-Oct-20 09:34 PM The mod was upset that I was insensitively contradicting a victim’s narrative. I was upset that people aren’t listening to science, and this is a really big deal because people are needlessly DYING right now all because some people think they know better than public health officials. Not to mention other issues like global warming, vaccines causing autism.... 17-Oct-20 09:34 PM That got the mod’s attention. 17-Oct-20 09:45 PM Indeed it will. You'll also get flagged when you say "This is all Thoreau's fault." 17-Oct-20 09:45 PM shakes angryfist at Transcendentalism 18-Oct-20 08:20 PM If humans lived long enough we would all get some form of cancer eventually! Every male on earth has cancer cells in his prostate at some point. Reasonable caution is the key but humans are so binary in behavior. After all. We are politicizing a virus and the nature of hydrocarbons and chemistry. 18-Oct-20 08:20 PM I blame evangelicals and extreme environmentalists. The crappy two verniers on the plywood of society screwing up the ways forward. 19-Oct-20 08:15 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-AF986.png 19-Oct-20 08:15 AM let's see if this works out 19-Oct-20 08:15 AM the caps on the right give a nice snap, and if that doesn't work out I can still replace the caps with amplifiers and use the thing as proporional counter like the ludlum 43-44 19-Oct-20 09:56 AM Alpha spark detector? 19-Oct-20 09:58 AM Yipyip! 19-Oct-20 10:00 AM Have not seen one done on a PCB before, will be interesting to see if it works 19-Oct-20 10:00 AM http://www.griffithobservatory.org/exhibits/edgeofspace_cosmicrays.html 19-Oct-20 10:00 AM A spark chamber would be a cool project too 19-Oct-20 10:04 AM oh yes 19-Oct-20 10:05 AM https://halverscience.net/Spark_Chamber/Spark_chamber_files/Spark_chamber_files.html 19-Oct-20 10:05 AM also now that I'm thinking about it I've never seen a cloud chamber in a magnetic field? 19-Oct-20 10:05 AM Think that is from the refurb of that Griffith observatory one 19-Oct-20 10:05 AM Peltier driven cloud chambers are way underdone... 19-Oct-20 10:05 AM Some day I gotta throw one together 19-Oct-20 10:07 AM I'd love to have one hanging on a wall 19-Oct-20 10:07 AM but that doesn't seem doable 19-Oct-20 10:14 AM so many detectors I still want to build 19-Oct-20 10:28 AM Trying to remember where I have seen spark chambers IRL before is driving me nuts... I know I have seen the Griffith Observatory one...but also remember one somewhere in the eastern half of the USA? Just can't place it and it was probably 20yrs ago now because I was just a kid... 19-Oct-20 10:33 AM never seen one irl 19-Oct-20 01:33 PM i saw one at DESY 19-Oct-20 01:33 PM pretty impressive i think it was something like 4-5m^3 19-Oct-20 01:34 PM geez 19-Oct-20 01:34 PM still have to visit DESY 19-Oct-20 01:34 PM know some people there (I think we know the same ones?) that offered me a tour 19-Oct-20 01:34 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190915_182641-9C7ED.jpg 19-Oct-20 01:34 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190915_182719-A847E.jpg 19-Oct-20 01:34 PM that's the biggest detector I've seen so far, bubble chamber at cern 19-Oct-20 01:53 PM https://en.wikipedia.org/wiki/Georgia_Nuclear_Aircraft_Laboratory The site was used for irradiating military equipment, as well as the forest 19-Oct-20 01:53 PM wht the hell 19-Oct-20 02:59 PM It's a very cool place. 19-Oct-20 03:00 PM I mean I don't doubt that 19-Oct-20 03:00 PM but 19-Oct-20 03:00 PM irradiating the forest 19-Oct-20 03:38 PM Seems like an interesting research project 19-Oct-20 03:38 PM Like one of those agricultural fields set up with a strong source that can be raised up in the middle for mutation breeding/research 19-Oct-20 03:38 PM http://www.naro.affrc.go.jp/archive/nias/eng/org/GR/IRB/ 19-Oct-20 03:38 PM https://www.google.com/maps/search/2425,+Kamimurata,+Hitachiohmiya,+Ibaraki+319-2293,+Japan/@36.527282,140.392935,463m/data=!3m1!1e3?hl=en 19-Oct-20 09:48 PM I had a chance to work with a chilled cloud chamber. It was pretty nifty. 19-Oct-20 09:48 PM Pump for the ethanol, heated trough to vaporize it, HV electric field to push the tracks down, I think the table itself was Peltier cooled, or chilled via some other means. 19-Oct-20 09:48 PM We built a lead target for it and tried to demonstrate pair production. 19-Oct-20 09:51 PM The exploratorium has a really nice cloud chamber table 19-Oct-20 09:51 PM I guess I could make one too now that I have a ton of heat pumps 19-Oct-20 09:51 PM I think we tried putting the equivalent of a refrigerator magnet on the base to bend the tracks. 19-Oct-20 09:51 PM It didn’t have enough strength. 19-Oct-20 09:51 PM This was for a science museum in Aurora, IL. I used to work for them when I was in high school and helped build exhibits. 19-Oct-20 10:17 PM I wish every high school had a cloud chamber 19-Oct-20 10:17 PM It is such a visceral science demonstration 19-Oct-20 10:43 PM For a while decades ago, most every school in CA did have one. Luis Alvarez, his students, and Oppenheimer's boys cranked them out for anyone and everyone that wanted one. The one at the Exploratorium is one of theirs and still kicking. 20-Oct-20 08:02 AM Soviet schools had them. We found one at the technical school at Mashevo, in the northern part of the Chernobyl Exclusion Zone near the Belarus border. 20-Oct-20 08:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSCN2133-60C65.JPG 20-Oct-20 08:13 AM The needle sources were interesting. 20-Oct-20 08:13 AM I believe we identified a Ra-226 source. But the alpha source was Pu. It's interesting that Soviets have so much Pu they can use it for industrial smoke detectors and high school science experiments. 20-Oct-20 08:22 AM one of those smoke detectors is definitely on my want list 20-Oct-20 08:25 AM Carl Willis did a really amazing analysis of the isotopic composition of Soviet smoke detector Pu. 20-Oct-20 08:25 AM Totally practical, all things considered. Kids in the US get Po-210 alpha sources that have to be regularly replaced. A Pu source doesn’t have that problem. 20-Oct-20 08:36 AM I know about carls page 21-Oct-20 05:59 PM I just saw this was published. 21-Oct-20 05:59 PM http://fuel-design.com/publishing/chernobyl-stalkers-guide/ 21-Oct-20 05:59 PM I don’t own this / haven’t read this so no opinion. 21-Oct-20 08:35 PM sigh 22-Oct-20 12:40 PM https://www.youtube.com/watch?v=w_6K6arW3h4 A nice view for the evening 23-Oct-20 05:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201023_141841-89775.jpg 23-Oct-20 05:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201023_141856-99D23.jpg 23-Oct-20 05:20 AM owo 23-Oct-20 11:53 AM What's inside? 23-Oct-20 11:55 AM 16x16 CZT array 23-Oct-20 11:55 AM plus preamps and readout 23-Oct-20 11:55 AM and all asics 23-Oct-20 07:49 PM Cool old meter 23-Oct-20 07:49 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-6F357.jpg 24-Oct-20 12:33 AM nwat! 24-Oct-20 12:33 AM what detector does it take? 24-Oct-20 12:34 AM I think it’s a scintillator actually 24-Oct-20 12:35 AM oh wow 24-Oct-20 12:35 AM These would attach to the pmt 24-Oct-20 12:35 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-E5645.jpg 24-Oct-20 12:35 AM that range kinds indicates ionisation chamber 24-Oct-20 12:35 AM attach to the pmt how? I am not even sure what the pic is showing 24-Oct-20 12:36 AM Yeah, that had been my thought too but I think those have a small scintillator at the tip and then a light pipe down to the brass disk 24-Oct-20 12:36 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-5440B.jpg 24-Oct-20 12:36 AM ohh, lol 24-Oct-20 12:37 AM It’s meant to go inside things (including body cavities) 24-Oct-20 12:37 AM kinky 24-Oct-20 12:37 AM at 25 R/H do you really need to do an internal measurement 24-Oct-20 12:39 AM I found a paper that used it that was measuring dose rates from Brachytherapy sources 24-Oct-20 12:39 AM But I have no idea why we have it 24-Oct-20 12:43 AM do you produce those sources in the reactor? 24-Oct-20 12:46 AM Not recently 24-Oct-20 12:46 AM Might have 40 years ago 24-Oct-20 12:46 AM More likely it was something someone got for free 24-Oct-20 12:46 AM Because the darn thing is old enough to be vacuum tube based 24-Oct-20 12:48 AM ohh cool 24-Oct-20 12:48 AM I don't think I've ever seen a tube based meter irl 24-Oct-20 12:48 AM my oldest stuff are my ludlum m12, and they're from the 60s 24-Oct-20 12:48 AM no wait I did 24-Oct-20 12:48 AM work place of otto hahn 24-Oct-20 12:48 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/3_angekommen_Vitrine_besser_159-59149.png 24-Oct-20 12:48 AM big, tube based geiger counter 24-Oct-20 12:50 AM Oh wow 24-Oct-20 12:50 AM look at those anode batteries down there! 24-Oct-20 12:53 AM I know there was at least one research reactor with a vacuum tube based console up until recently 24-Oct-20 12:54 AM I am not sure between "never change a running system" and "this could fail any second now" 24-Oct-20 12:55 AM Eh, it was a triga 24-Oct-20 12:55 AM Worst case scenario they cut power and it’s safe 24-Oct-20 12:56 AM fair 24-Oct-20 12:56 AM but still 24-Oct-20 12:56 AM Yeah, doesn’t matter anymore 24-Oct-20 12:58 AM I’m sure many people still have tube-based HVPSUs running 24-Oct-20 12:58 AM They closed up shop for good in 2018 though they’d been defuled for a while prior due to regulatory issues after the company technically became foreign owned 24-Oct-20 01:00 AM so many research reactors get closed down but none are opened up 24-Oct-20 01:01 AM Don’t remind me 24-Oct-20 01:01 AM don't tell me yours is going down as well 24-Oct-20 01:01 AM We aren’t 24-Oct-20 01:01 AM phew 24-Oct-20 01:01 AM Just hired a new director 24-Oct-20 01:02 AM oh fun 24-Oct-20 01:09 AM Yeah, and we just finished license exams today for a bunch of people 24-Oct-20 01:09 AM That was a fun time 24-Oct-20 01:17 AM honestly, that actually sounds like fun 24-Oct-20 01:18 AM Ehhhh, it’s stressful because the exams are given by people from the NRC 24-Oct-20 07:20 AM Judging by the components used that is from the 20’s and a couple of the tubes in the back were replaced with ST types in the 30’s or so. The globe shaped ones with the magnesium getters would have been only been available for a short window of time in the 20’s and very early 30’s and the world VERY QUIcKLy moved away from those types when barium getter versions became available. 24-Oct-20 07:20 AM Also those old Pertrix batteries, otherwise known as Hittlers Choice. They were known for using forced labor. Those are 90 volt with multi taps each. 24-Oct-20 10:46 AM https://www.youtube.com/watch?v=gEKHP2fnWOk 24-Oct-20 11:15 AM That radiation induced color change in the glass is really interesting 24-Oct-20 11:16 AM I have one sample that has suffered the same fate 24-Oct-20 11:16 AM although it just turned brown 24-Oct-20 11:16 AM Today was a good day, I sorted through all my active stuff and cataloged it, measured dose rate and packed it in tins 24-Oct-20 11:16 AM now I am looking for a safe to store them in 24-Oct-20 11:43 AM Oh the purple color change? 24-Oct-20 11:43 AM I learned recently table salt will turn yellow after high doses of radiation 24-Oct-20 11:46 AM and KCl will exhibit thermoluminescense! 24-Oct-20 11:46 AM As will NaCl if I’m correct 24-Oct-20 11:46 AM Might try that this afternoon because I found a bottle of irradiated salt 24-Oct-20 11:46 AM right, NaCl as well 24-Oct-20 11:47 AM I’m going to be doing some water analysis just as practice so I’ll be in the radiochem lab anyway 24-Oct-20 11:47 AM oh NaCl turns yellow orange and KCl turns purple! 24-Oct-20 11:47 AM http://www.nuclearphysicslab.com/npl/npl-home/experiments/thermoluminescence/ 24-Oct-20 11:47 AM I wonder if one can do the same with a commercial x-ray system 24-Oct-20 11:51 AM Depends on if there’s a minimum photon energy needed or not 24-Oct-20 11:51 AM And if you can run the x-ray long enough 24-Oct-20 11:52 AM yep 24-Oct-20 11:53 AM The long xray use is probably the sticking point I’d imagine 24-Oct-20 11:53 AM The dose needed is kinda insane 24-Oct-20 11:53 AM although I don't think that the minimum energy is that high 24-Oct-20 11:53 AM run time is what concerns me 24-Oct-20 11:53 AM yep 24-Oct-20 12:33 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-A38BB.jpg 24-Oct-20 12:33 PM I’m only Millhouse when he gets hurt. 24-Oct-20 12:33 PM Still one of the best simpsons episodes ever 24-Oct-20 01:00 PM Yeah.... Carl found something spicy.... 24-Oct-20 01:02 PM I'm surprised how relaxed he is around it 24-Oct-20 01:02 PM 120 mg of Ra in equilibrium with its daughters does gives 3 mSv/h at 50 cm 24-Oct-20 01:14 PM I believe that was 120 uCi / ug. 24-Oct-20 01:19 PM what? 24-Oct-20 01:19 PM Ra is 1 Ci per g 24-Oct-20 01:19 PM that's the definition of Ci 24-Oct-20 01:19 PM so 120 mg of Ra are 120 mCi 24-Oct-20 01:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D99C1.png 24-Oct-20 01:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6D30D.png 24-Oct-20 01:42 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-9DC5A.png 24-Oct-20 01:42 PM Micro not milli. 24-Oct-20 01:43 PM ohh, then I misunderstood him 24-Oct-20 01:44 PM Still 120 uCi is nothing to sneeze at, but it’s not DROP AND RUN levels of spice, either. 24-Oct-20 01:44 PM yeah 25-Oct-20 03:17 AM dang it 25-Oct-20 03:17 AM I need a good dosimeter 25-Oct-20 03:17 AM dose rate measurement thingie 25-Oct-20 03:17 AM my stuff only starts at 2 µSv/h 25-Oct-20 04:00 AM what is the point of pressurizing an ion chamber? 25-Oct-20 04:02 AM higher density / macroscopic cross section? 25-Oct-20 04:02 AM just more stuff to interact with 25-Oct-20 04:04 AM oh, guess that makes sense 25-Oct-20 04:04 AM was thinking that higher pressure would mean a correspondingly higher breakdown threshold 25-Oct-20 04:06 AM also that, but since there's no amplification in an ion chamber it doesn't matter much at what voltage you drive it 25-Oct-20 11:37 AM Pressurized is also are a design prereq for RF shielding your ion chamber for accelerator applications/pulsed systems. AKA "the nice ion chamber" that people keep on hiding when you need it. 25-Oct-20 11:38 AM oh! 25-Oct-20 11:38 AM why's that? 25-Oct-20 11:42 AM Because they're more expensive, you tend to have one pressurized RF shielded ion chamber to every 10+ normal atmospheric chambers. But if you need that one all the time for your work, you tend to hold on to it and hide it to make sure it doesn't go walking. There's never enough of them and when someone else needs one, it's almost always been squirreled away. Very annoying but I am also totally guilty of doing that. 25-Oct-20 11:43 AM nono, I get why they're hidden, but why is pressurized better in RF 25-Oct-20 11:46 AM Nothing complicated. You have a sealed chamber body that you can then make your shielding around. Not as easy to get away with that with atmospheric. 25-Oct-20 11:47 AM ahh 25-Oct-20 11:47 AM pressurized needs a thicker wall because of mechanical stability, and that thicker wall is inherently better at shielding 25-Oct-20 11:51 AM Also, for older meters you need to do some work on the meter movement and electronics themselves to protect from RF. I had an old Bicron that politely let me know it was useless in the accelerator environment by how the needle fully deflected and came back to zero to the Rhythm of the Drivers. Until, of course, it broke. 25-Oct-20 11:51 AM rip 25-Oct-20 12:26 PM ooh, interesting! 25-Oct-20 12:54 PM kinda wanna build an ion chamber now 25-Oct-20 12:54 PM kinda don't wanna build an ion chamber preamp 25-Oct-20 12:54 PM pA / nA level stuff is hard enough as it is but with long term stability... :v 25-Oct-20 01:21 PM time to mod one of those ion gauges 25-Oct-20 01:22 PM There's an ion chamber I have that uses about 2kv and a high pressure propane chamber 25-Oct-20 01:22 PM I've got some pA and nA stuff going on now with nanopore r&d... It's surprisingly easier than I thought... Just using the Texas Instruments suggested layout for their transimpedance amplifier 25-Oct-20 01:24 PM oh wait, no, that just calls itself an ion chamber but is actually a proportional tube, nevermind 25-Oct-20 01:24 PM This layout https://www.ti.com/tool/LMP7721MAEVALMF_NOPB#technicaldocuments 25-Oct-20 01:24 PM i have an ancient and uncalibrated keithley 26000 logarithmic picoammeter that i don't know how to use, or if it works still 25-Oct-20 01:24 PM but i did kind of get it with that and/or a faraday cup application in mind 25-Oct-20 01:25 PM I've also got some keithley rackmount picoammeter that I was thinking of using for a faraday cup in my FIB for milling endpoint detection 25-Oct-20 01:25 PM someday 25-Oct-20 11:29 PM there’s a funny moment skimming back through messages on a server and seeing the word AMBE come up and getting very confused about a neutron source before realizing they meant the radio voice codec 26-Oct-20 12:56 AM has anybody here ever tried laser cutting plastic scintillators? 26-Oct-20 12:56 AM esp. the PVT kind 26-Oct-20 12:56 AM BC408 / 412 26-Oct-20 08:08 AM Do you have the chemical composition of the scint? 26-Oct-20 08:08 AM Never laser cut any plastic containing chlorine. 26-Oct-20 08:08 AM Produces chlorine gas. Even if you’ve got excellent fume extraction, the Cl gas will destroy the laser lens. 26-Oct-20 08:09 AM yes, PVT and some fluor 26-Oct-20 08:09 AM Even worse. 26-Oct-20 08:10 AM not sure what the latter is but prretty much none has chlorine 26-Oct-20 08:10 AM fluor, not fluorine 26-Oct-20 08:10 AM I don’t want fluorine gas anywhere near a lens. 26-Oct-20 08:10 AM fluor is the "active component" 26-Oct-20 08:11 AM Fl is in an even worse spot on the periodic table than Cl. 26-Oct-20 08:11 AM what? 26-Oct-20 08:11 AM no fluorine involved 26-Oct-20 08:11 AM https://en.wikipedia.org/wiki/POPOP 26-Oct-20 08:11 AM stuff like this 26-Oct-20 08:11 AM in lots of PVT 26-Oct-20 08:12 AM Oh sorry. 26-Oct-20 08:12 AM That sounds safe then. But the next question is what the heat affected area will do to the optical properties. 26-Oct-20 08:12 AM I’m assuming this is not for spectroscopy, so it may not matter so much. 26-Oct-20 08:16 AM plastic is never for spectroscopy ^^ 26-Oct-20 08:16 AM I’ve heard of people improving resolution by all sorts of custom polishing and treating of edges, etc. but that doesn’t sound applicable. 26-Oct-20 08:16 AM It sounds like it’s worth a try. 26-Oct-20 08:16 AM Also how thick is the scint and how powerful is the laser? 26-Oct-20 08:17 AM the laser I currently have access to is 30W CO2, but 150W is also possible 26-Oct-20 08:17 AM and scinti... haven't looked at anything yet, am just thinking about it as there are many bigger ones on ebay 26-Oct-20 08:19 AM Most hobbyist lasers are going to be thickness limited. They’re designed for sheet goods, like 1/8” to 1/4”. 26-Oct-20 08:20 AM I've been told 10 mm of PMMA is possible if I don't care about the edge finish (will be somewhat triangular) with the 30W one 26-Oct-20 08:20 AM I think a half" scintillator should be possible to cut 26-Oct-20 08:20 AM if it cuts anything like PMMA 26-Oct-20 08:20 AM if it's more like PS it might melt back together after cutting 26-Oct-20 08:22 AM Have you given thought to CNC milling? Even a small Shapeoko could do a good job. 26-Oct-20 08:22 AM I did but I just recently got permission for the cutter and now I want to play with it 26-Oct-20 08:34 AM Ahhh ok. 26-Oct-20 08:34 AM Unless you have small inside corners, I’d think you’d get better results with a CNC router. 26-Oct-20 08:34 AM But... when your only tool is a hammer, all of your problems suddenly seem to look like nails. 26-Oct-20 08:36 AM also with CNCed stuff I'll have to polish afterwards 26-Oct-20 08:36 AM which I don't when using the laz0r 26-Oct-20 08:38 AM Fire the lazzor! pew pew 26-Oct-20 09:22 AM @GigaSquirrel the guy who sells it on eBay cuts it with a bandsaw into chunks 26-Oct-20 11:35 AM So if I was doing alpha particle spectroscopy, is there a way to work out how much peak broadening I'll get at various levels of vacuum or does it have to be done experimentally. 26-Oct-20 11:37 AM I’d be interested in seeing those results. 26-Oct-20 11:46 AM oh wait nevermind, answered my own question 26-Oct-20 11:46 AM https://www.stuk.fi/en/web/en/services/aasi-program-for-simulating-energy-spectra-in-alpha-spectrometry 26-Oct-20 11:46 AM now just to get it running 26-Oct-20 11:46 AM https://www.stuk.fi/web/en/services/aasi-program-for-simulating-energy-spectra-in-alpha-spectrometry/thank-you-for-your-registration-download-the-aasi-program 26-Oct-20 11:46 AM lol 26-Oct-20 11:46 AM download page is just open 26-Oct-20 12:40 PM IDK about alpha particle stuff, but collisional broadening in general is one of the easier line broadening things you can calculate? 26-Oct-20 05:59 PM Silly little beta particle induced xrf test 26-Oct-20 05:59 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-7C9CE.jpg 26-Oct-20 05:59 PM Bismuth and lead with the main peak being bismuth 27-Oct-20 12:29 AM https://www.youtube.com/watch?v=UK8RIJn88Y0 27-Oct-20 12:29 AM @Addison-110m very clean spectrum, HPGe? 27-Oct-20 12:29 AM what source did you use? 27-Oct-20 12:39 AM Yeah HPGe, it was just with a ~3kbq 90Sr source 27-Oct-20 12:39 AM so 3kbq 90Sr plus an equal quantity of 90Y 27-Oct-20 12:39 AM i'm surprised I had a strong signal at all with such a small source 27-Oct-20 12:39 AM though that was after half an hour 27-Oct-20 12:40 AM oh neat 27-Oct-20 12:40 AM gotta try that, my Sr/Y90 source is a bit hotter than that 27-Oct-20 12:41 AM yeah I could have got a warmer source but this was fast 27-Oct-20 12:41 AM would be interesting to try with 32P... 27-Oct-20 01:34 AM fascinating, that hasn't got any gammas either 27-Oct-20 10:22 AM yeah, just using the beta particles to cause it, and it means less interference potentially 27-Oct-20 10:28 AM you've basically built a spectral x-ray tube 27-Oct-20 10:28 AM something like that 27-Oct-20 10:28 AM an insanely weak one at that 27-Oct-20 10:29 AM I bet @funranium still would have some issues with it 27-Oct-20 10:30 AM lol 27-Oct-20 12:30 PM I mean, I own three of those coins . The activation was timed to be cool enough by the time you walked out of the museum. Or World Expo, as the case maybe. Depends where the "neutron howitzer" demo was set up. You have all the fun you want making your source based "tube". Now you can have all the filtration experiments you've ever wanted. 27-Oct-20 12:48 PM filtration experiments? 27-Oct-20 12:48 PM I mean, I could and honestly might, scale this up and see if it's reasonable to be something that could be used for anything practical. (perks of working at a reactor) There are a bunch of nonactive metal samples that I need to identify 27-Oct-20 01:53 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/ElXISWgU0AEUasu-A5AA1.png 27-Oct-20 06:29 PM Wow 27-Oct-20 06:29 PM And yikes, not a room I’d be thrilled to work in 27-Oct-20 06:29 PM Even with solid safety design 27-Oct-20 09:34 PM It is very much one of those “This happened decades ago and not anymore because we learned a lot of valuable lessons over those decades” situations. 28-Oct-20 02:14 AM I always imagine curie as grams of radium 28-Oct-20 02:14 AM and the thought of an 13 kg Radium brick is... scary to say the least 28-Oct-20 11:46 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_3248-F9F9B.jpg 28-Oct-20 11:46 AM TRIGA reactor power channel neutron detector (came across it at work a few days ago, not mine) 28-Oct-20 11:46 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_3247-EE178.jpg 28-Oct-20 11:46 AM ohhh 28-Oct-20 11:46 AM self powered? 28-Oct-20 11:46 AM It's a compensated ion chamber with two chambers, one boron lined one not 28-Oct-20 11:46 AM or ion chamber? 28-Oct-20 11:46 AM ahh 28-Oct-20 12:21 PM https://www.youtube.com/watch?v=VWYOt2PiQR4&feature=emb_title Retro computing and radioactivity! 28-Oct-20 01:38 PM oh that's cool :D didn't know the 2200 had a whole RS-232 interface 28-Oct-20 01:38 PM i lent an amber-screen VT-420 dumb terminal out to a friend years ago and i only slightly regret it now bc it would make a nice ROI tagging punchin/punchout interface for my Series 35+ MCA 28-Oct-20 01:41 PM can't you get it back? I mean if it's just lent 28-Oct-20 01:41 PM unfortunately she's also using it pretty frequently and i might just try and get another one 28-Oct-20 01:41 PM ah well 28-Oct-20 01:41 PM (go get a red pitaya) 28-Oct-20 01:42 PM it has tempted me a few times now! 28-Oct-20 01:42 PM but, then, i'm also only a ribbon cable or two from having a third MCA, so maybe i don't need more.. 28-Oct-20 01:42 PM although, portable.. 28-Oct-20 01:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201026_204035-9B84B.jpg 28-Oct-20 01:45 PM common you want it 28-Oct-20 01:45 PM I finally got to order the HVPS for this thing 28-Oct-20 01:45 PM now if the prototype PCBs weren't stuck in customs I could test it all and order the proper PCBs for the case 28-Oct-20 01:45 PM and the it would be done 28-Oct-20 01:45 PM finished 28-Oct-20 01:45 PM I don't know for how many years I wished I had a portable gammaspec 28-Oct-20 01:45 PM if it wasn't for The Pandemic ™️ I'd probably visit this place first and take spectra of their cubes https://www.youtube.com/watch?v=xVG5lWn4hd8 28-Oct-20 02:18 PM heh 28-Oct-20 02:22 PM starting to get a bit frustrated tbh 28-Oct-20 02:22 PM so many things I wanted / want to do this year that just won't happen 28-Oct-20 10:39 PM @qualia don't feel bad... DEC terminals are stupid common... I have a whole shelf of them :P 28-Oct-20 10:39 PM I think I have more DEC terminals than turbo molecular pumps? 29-Oct-20 10:47 AM https://youtu.be/PEgCZLvfgX8 29-Oct-20 10:47 AM I love the little robot doggo anti-contamination paw covers. 29-Oct-20 10:47 AM No sign of it twerking to Uptown Funk. 29-Oct-20 01:03 PM I may or may not have gotten a chance to x-ray my HPGe 29-Oct-20 01:03 PM the planar one I still need to repair 29-Oct-20 01:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2020-10-29_18-06-15-9305E.jpg 29-Oct-20 01:03 PM now I kind of know what to expect in there, I think I can see the fet 29-Oct-20 02:06 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/P1030966-13660.JPG 31-Oct-20 01:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Eln3aRxU0AAJIa4-8D783.png 31-Oct-20 01:55 AM What am I looking at and should I be concerned? :P 31-Oct-20 01:57 AM yes 31-Oct-20 01:57 AM :P 31-Oct-20 01:57 AM https://www.sciencemag.org/news/2017/06/near-disaster-federal-nuclear-weapons-laboratory-takes-hidden-toll-america-s-arsenal 31-Oct-20 02:02 AM What in the? 31-Oct-20 02:02 AM This is scary to read 31-Oct-20 02:06 AM which makes this pic I posted even worse 31-Oct-20 04:00 AM Boi 31-Oct-20 04:00 AM It's almost like, workers don't listen to training 31-Oct-20 04:00 AM Who would have thought 31-Oct-20 04:00 AM It's for this reason primarily I don't have much faith in nucelar industry 2.0 being a viable green energy provider. Humans are prone to error and the errors here are way more expensive than the alternatives. 31-Oct-20 04:00 AM A DC arc fault from a string of PV panels is bad but not like, criticality in a 5 gallon bucket bad. 31-Oct-20 04:36 AM https://www.youtube.com/watch?v=VE8FnsnWz48 31-Oct-20 10:23 AM There’s a bit more than “it’s a training issue” to this particular incident. It’s much more an problem of bringing profit motive to things like stockpile stewardship. There are things you don’t make a profit on and, in fact, seems rather immoral to think you can. In LANL’s latest near miss there, it’s because they’d more or less gutted their criticality safety program. You know, the people who’d have said “Don’t do that!” before the thing they did. At last check, it was still a skeleton crew too. 31-Oct-20 11:18 AM https://twitter.com/GovNuclear/status/1322591786632728576 31-Oct-20 11:18 AM Nice little video but there could have been more footage of actual testing... 31-Oct-20 04:01 PM a lot of the national labs' social media/youtube teaser video fare from at least the last couple of years leaves a whole lot to be desired.. too much fluff 31-Oct-20 04:01 PM shame, really, the tech is often way too cool to keep putting tired soulless minutes-before-retirement ppl in front of cameras to play natsec butt-kiss when actually talking about the tech would ostensibly work so much better for recruitment anyways 31-Oct-20 04:01 PM dear sandia plz pander to my interests harder love qualia 31-Oct-20 04:16 PM I liked Linus tech tips ligo and triumf 31-Oct-20 06:54 PM Interesting alpha spectroscopy simulation. 5MeV particles 1cm from the detector. From left to right a 0.001225g/cm3 N2 (regular air density), 0.0001225g/cm3 N2, and a pure vacuum. Interesting how much of a difference even a relatively weak vacuum makes 31-Oct-20 06:54 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-FB5EA.png 01-Nov-20 07:11 AM I had a friend who worked at Los Alamos during those years. She said it was an Us vs them attitude that went all the way back to the Manhattan project days. They did not want too many smart people working at technicians. Only the anointed brains from Cal (which she was one of) we’re allowed to know what was really going on. Exit thoughts before she completely changed fields were basically the only people who should be working there were actual professional engineers from the managers down to the guy sweeping the floor but that goes against the way they do things. That will not happen until there is political will to make it happen. 01-Nov-20 07:11 AM She also worked at white sands for a while. She changed her field from Geology/Chemistry to Geology/gemology when she realized her only options in that field were in African or Russian uranium mines! 01-Nov-20 09:18 AM That’s interesting, @Addison-110m I was trying to get a reasonable estimate of vacuum on my alpha spec but the Pirani gauge was messed up beyond possibility of calibration. 01-Nov-20 10:17 AM Oh blegh. For me I was mostly interested in how much resolution loss I’d get using something like a water aspirator vacuum or an air sampling pump. Probably not enough that I’d really notice all that much, especially if I could bring the distance down to mm or two 01-Nov-20 10:22 PM hmmm some place is selling one of these 01-Nov-20 10:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/morgan_mini_900_scintillation__1600067312_-E32FD.png 01-Nov-20 10:22 PM hmmm I wonder 01-Nov-20 10:22 PM Gamma and X-rays only 01-Nov-20 10:22 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5E5DD.png 01-Nov-20 10:22 PM I wonder how you'd even calibrate one of these 01-Nov-20 10:26 PM @ funranium hates those 01-Nov-20 10:26 PM You disconnect the gm tube internally and feed in pulses 01-Nov-20 10:26 PM Can you see the probe on the end? 01-Nov-20 10:28 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/morgan_mini_900_scintillation__1600067312_-F7DFB.png 01-Nov-20 10:29 PM hmm, that doesn't look right 01-Nov-20 10:29 PM that looks busted 01-Nov-20 10:29 PM is that your picture? 01-Nov-20 10:29 PM no 01-Nov-20 10:29 PM that's the seller's picture 01-Nov-20 10:29 PM Ah 01-Nov-20 10:31 PM there are some of these things floating around 01-Nov-20 10:31 PM there are also personal pocket sized radiation meters around 01-Nov-20 10:32 PM interior of one, you disconnect two of those wires, can't remember which, and feed in pulses to make sure them meter reeds correctly 01-Nov-20 10:32 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/M6wxWssON8Db1Rl0fc9sTMZYJR1Wdda8TjnCTn1TW5-F2406.png 01-Nov-20 10:32 PM there are about a million variations of mini-monitors 01-Nov-20 10:32 PM but that one looks like it's got a broken gm tube 01-Nov-20 10:32 PM fixable but annoying to do 01-Nov-20 10:33 PM looks like the National University of Singapore got rid of it 01-Nov-20 10:33 PM maybe that's why 01-Nov-20 10:33 PM ¯\_(ツ)_/¯ 01-Nov-20 10:36 PM maybe, though that's usually a repairable issue 01-Nov-20 11:28 PM that tube is very much dead 01-Nov-20 11:28 PM but they usually can be replaced 02-Nov-20 01:18 AM I am trying to get a group buy together, anybody interested in a 25x3 mm NaI with Be window? 02-Nov-20 01:18 AM NaI(Tl) scintillator for X-ray spectroscopy Crystal size: Dia. 25 mm x 3 mm Encapsulation: Aluminum housing, K9 glass window, beryllium entrance window will be $200 a pop, plus shipping 02-Nov-20 01:38 AM wow, super thin 02-Nov-20 01:38 AM great for <100 keV stuff 02-Nov-20 01:38 AM 3 mm is ~1/8" 02-Nov-20 01:38 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-19178.png 02-Nov-20 01:38 AM currently trying to figure out if they're vacuum compatible 02-Nov-20 01:45 AM know the thickness of the Be window? 02-Nov-20 01:45 AM or area density 02-Nov-20 01:47 AM eh 02-Nov-20 01:47 AM good point 02-Nov-20 01:48 AM i'm .. more interested than i should be for someone as not-employed as i am 02-Nov-20 01:48 AM seems like it could potentially make a good x-ray leakage detector probe 02-Nov-20 01:50 AM at three pieces it would be 180 a pop, plus 50 bucks shipping to me, plus whatever it costs to get it to your place 02-Nov-20 09:38 AM I might be interested as well 02-Nov-20 09:46 AM Great ^^ 02-Nov-20 09:46 AM how many sigma certainty you'll get one? :P 02-Nov-20 10:00 AM I do, indeed, hate those @SleepyOwl Joyce. If you get the Mini-Monitor, you are going to get the chance to become VERY proficient at cracking it open for calibration. If you look at it funny, it loses cal. If the food you had for dinner the previous night was too spicy, it loses cal. The complimentary thing I have to say about them is that their speaker has a good clicky noise, when it bothers to actually detect something. Probe performance vs. meter display are in passing agreement at best. 02-Nov-20 10:00 AM They are the finest of shoddy 1970s British design and, in very British fashion, have seen no need to improve it. 02-Nov-20 10:01 AM spicy food can be compensated with Background substraction 02-Nov-20 10:02 AM interesting. 02-Nov-20 10:02 AM @GigaSquirrel what happens if I ate a whole bunch more bananas? 02-Nov-20 10:03 AM you'd need a lot of bananas 02-Nov-20 10:03 AM Thank you for this birthday gift to share my hate for Mini-Monitor anew. 02-Nov-20 10:04 AM and also Happy Birthday :P 02-Nov-20 10:04 AM Happy birthday? 02-Nov-20 10:04 AM Thank you! 02-Nov-20 10:04 AM you'd need a lot of bananas @GigaSquirrel speaking of which there is this video 02-Nov-20 10:04 AM https://www.youtube.com/watch?v=z9LgUlKNGFg 02-Nov-20 10:05 AM https://www.youtube.com/watch?v=OGldNpngDws 02-Nov-20 10:05 AM you'd go bananas quick 02-Nov-20 10:05 AM (also I admit I might have fallen asleep watching that video I posted) 02-Nov-20 10:05 AM RadioactiveASMR 02-Nov-20 10:12 AM the sound of the mini Monitor is one of my favorite Things about it! 02-Nov-20 10:12 AM https://youtu.be/WbKoB_4QQ5U 02-Nov-20 10:12 AM https://youtu.be/1X6NKbSn-T8 Also to be heard here, at a bit higher radiation levels 02-Nov-20 10:12 AM ...man this was a scary source, I loved working with it 02-Nov-20 10:16 AM how do you get your hands on sources like that anyhow? 02-Nov-20 10:19 AM ask nicely 02-Nov-20 10:19 AM show people you can be trusted 02-Nov-20 10:20 AM fair 02-Nov-20 12:16 PM Happy birthday! @funranium 02-Nov-20 03:14 PM Thank you! 02-Nov-20 10:22 PM https://tenor.com/bhWT3.gif 04-Nov-20 10:49 PM What should I do with this 04-Nov-20 10:49 PM https://adammunich.com/nuclear-bomb-detector/ 04-Nov-20 10:49 PM It's been more than a decade and it hasn't been turned into anything cool yet 04-Nov-20 11:01 PM Send it to me 04-Nov-20 11:01 PM :P 04-Nov-20 11:02 PM no send it to me 04-Nov-20 11:02 PM along with some fissile material 04-Nov-20 11:02 PM then soon I will hold the world hostage muahahahahahahahahaha 04-Nov-20 11:02 PM knocking on the door 04-Nov-20 11:02 PM Ma'am please follow us to the mental institution, we suspect you might be in need of mental health care 04-Nov-20 11:04 PM Send it to me Or me, I’ll turn it into a delayed neutron activation analysis setup 04-Nov-20 11:05 PM honestly, don't send it to me 04-Nov-20 11:05 PM Which I just read about and now really want to try and get set up at work 04-Nov-20 11:05 PM the police will be up my butt real quick lol 04-Nov-20 11:05 PM But I can find a detector in our back room somewhere 04-Nov-20 11:05 PM Singapore is awful paranoid about lots of stuff 04-Nov-20 11:05 PM so non-radiation related - my uncle was really into Chinese culture and history 04-Nov-20 11:05 PM so he once tried ordering books about communism in China 04-Nov-20 11:05 PM post office asked him to go down to collect the package for some reason 04-Nov-20 11:05 PM but he was out of town so he got his brother to do it 04-Nov-20 11:05 PM guess what? His brother shows up and immediately gets arrested 04-Nov-20 11:05 PM I am pretty sure nuclear bomb detectors... 04-Nov-20 11:05 PM ehhhhh 04-Nov-20 11:13 PM the great part about science/tech hobbies is that you have a decent shot of being ignored as an eccentric but not really dangerous/threatening/etc as long as you keep away from drugs and energetic materials 04-Nov-20 11:14 PM is that so? 04-Nov-20 11:14 PM 'cause I have to say if someone had my ebay search history... 04-Nov-20 11:14 PM thats been my experience but i do have a knack for talking my way out of things 04-Nov-20 11:15 PM never had to talk my way out of legal things so far 04-Nov-20 11:16 PM mostly just trespassing issues for me plus a couple times when i wasn't doing anything wrong but was "suspicious" 04-Nov-20 11:17 PM ah, heh 04-Nov-20 11:17 PM easy to make people brush you off as an eccentric overly interested person if you ask them some questions about the area you are not supposed to be in 04-Nov-20 11:17 PM A fishing pole gets you a free pass on any coastal property in america lol 04-Nov-20 11:17 PM I only was searched for drugs a few times by the police, because I usually was out late and look(ed?) like I was done with this sh't 04-Nov-20 11:17 PM my favorite was the time that backfired on me completely and i had to convince a group of cops my purple flashlight (UV) really was to find scorpions 04-Nov-20 11:18 PM only time things ever escalated beyond just explaining why i was where i was 04-Nov-20 11:18 PM Singapore is awful paranoid about lots of stuff @SleepyOwl Joyce how about radium chewing gum 04-Nov-20 11:19 PM I'd be paranoid about that, too 04-Nov-20 11:20 PM scorpions? 04-Nov-20 11:21 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/44bc3f765f3e41d1c43038190971880b-66D30.png 04-Nov-20 11:21 PM all the fluorescence 04-Nov-20 11:21 PM ah 04-Nov-20 11:22 PM I wonder if they scintillate 04-Nov-20 11:22 PM i used to sell them heh 04-Nov-20 11:22 PM now i just catch them for my girlfriend hehe 04-Nov-20 11:23 PM build a giant cosmic shower telescope by pointing PMTs down towards the scorpions 04-Nov-20 11:23 PM why do people buy them? 04-Nov-20 11:23 PM to keep as pets mostly 04-Nov-20 11:23 PM @adammunich Posession of 3He detectors shouldnt be an issue, however trying to export it from US definitely might be problem. I know that our "radiation detection team" had to do some serious paperwork to get 3He detectors bought... 04-Nov-20 11:24 PM i donated a handful of specimens to a research project too revising a genus of scorpions but i think they had issues processing them 04-Nov-20 11:24 PM none of the sequences ever got posted that i saw from my specimens anyway 04-Nov-20 11:24 PM It would be news to me that Neutron detectors were export controlled 04-Nov-20 11:24 PM ohhh did not even think of that 04-Nov-20 11:24 PM ITAR and other arms control stuff reach far and wide 04-Nov-20 11:25 PM Nah 04-Nov-20 11:25 PM usually things with you can easily determine enrichment are export controlled 04-Nov-20 11:25 PM HPGes, Alpha spectrometers, etc 04-Nov-20 11:26 PM how about radium chewing gum @adammunich tbh I was thinking of ordering rock samples of stuff that contain radioactive elements for future stuff 04-Nov-20 11:26 PM (also mass spectrometers that go above 230 amu!) 04-Nov-20 11:26 PM but I am paranoid of them being paranoid 04-Nov-20 11:26 PM I never got that, since you can easily determine enrichment with NaI as well 04-Nov-20 11:26 PM @SleepyOwl Joyce if you're looking for stuff to test geiger counters look for old watches with radium, or uranium glass etc 04-Nov-20 11:27 PM yeah 04-Nov-20 11:27 PM but I am thinking it would show up on X-ray machines and stuff like that 04-Nov-20 11:28 PM ordering mineral specimens is probably pretty safe as long as you are not buying extremely large samples 04-Nov-20 11:28 PM you should be able to get that local 04-Nov-20 11:28 PM I don't think so 04-Nov-20 11:28 PM i got some autunite from china and shockingly had zero problems 04-Nov-20 11:28 PM here literally every flea market and antique store has some 04-Nov-20 11:28 PM they're just old watches 04-Nov-20 11:28 PM or vases etc 04-Nov-20 11:28 PM seller wrapped it in aluminum foil in the box and i could pick it up on my geiger counter about half way across the room with one of the soviet pancake probes 04-Nov-20 11:29 PM yikes 04-Nov-20 11:29 PM that's warm 04-Nov-20 11:29 PM i got some autunite from china and shockingly had zero problems @LRM they're glad to get rid of it 04-Nov-20 11:29 PM I was expecting issues on the USA side of things but probably true haha 04-Nov-20 11:29 PM gets listed under crazy names 04-Nov-20 11:29 PM "green mica" and etc 04-Nov-20 11:29 PM ...wow 04-Nov-20 11:29 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-80134.png 04-Nov-20 11:30 PM lol 04-Nov-20 11:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-CE941.jpg 04-Nov-20 11:30 PM Speaking of uranium 04-Nov-20 11:30 PM Saw an amazing entry in the chem department database today 04-Nov-20 11:30 PM bwahaha 04-Nov-20 11:31 PM ️ 04-Nov-20 11:31 PM thats awesome haha 04-Nov-20 11:31 PM the fluorescence of autunite is shockingly vivid btw for anyone who has not experienced that first hand 04-Nov-20 11:33 PM I haven't 04-Nov-20 11:33 PM I have collected a few warm to hot stones but they only had a few mm² of weak fluorescence at max 04-Nov-20 11:33 PM was mostly pitch blende 04-Nov-20 11:34 PM my chunk of pitchblende is solid black...wish i knew where it came from originally 04-Nov-20 11:34 PM was a random rock sample i was given mixed in with some others 04-Nov-20 11:35 PM oh boy 04-Nov-20 11:35 PM one of the many reasons to always carry a geiger counter with you 04-Nov-20 11:35 PM didnt even know i owned it until i got one actually so i cannot argue with that at all 04-Nov-20 11:36 PM I need to get a smaller detector 04-Nov-20 11:37 PM smaller than? 04-Nov-20 11:37 PM my current one 04-Nov-20 11:37 PM which is rather large 04-Nov-20 11:37 PM well 04-Nov-20 11:37 PM average size 04-Nov-20 11:37 PM (I was hoping for a model number :P) 04-Nov-20 11:37 PM oh 04-Nov-20 11:37 PM build one around a LND714 tube like i did....will tell you if something is fiestaware or not 04-Nov-20 11:37 PM and if clocks have radium or not 04-Nov-20 11:37 PM Johnson GSM-10 04-Nov-20 11:37 PM and possibly extra spicy uranium glass haha 04-Nov-20 11:37 PM i am a little underwhelmed by it 04-Nov-20 11:38 PM I'm toying with ideas for a small scintillator 04-Nov-20 11:38 PM oh that one looks cute 04-Nov-20 11:38 PM whole lot of ideas possible there if you are willing to spend the $$$ 04-Nov-20 11:38 PM if you're looking for some scintillators there's a very good deal in #swap-meet 04-Nov-20 11:38 PM albeit they're not very small 04-Nov-20 11:42 PM I'll probably go with a small CsI, LYSO, or BGO crystal 04-Nov-20 11:43 PM SIPM or PMT? 04-Nov-20 11:43 PM not sure yet, have a few months to figure things out before i start working on it 04-Nov-20 11:50 PM would you be interested in a small-ish LaBr3 perhaps? 05-Nov-20 12:01 AM unfortunately not 05-Nov-20 12:01 AM This is meant to be something that can go out into the desert with me when it's not the primary reason I'm out there 05-Nov-20 12:02 AM heh 05-Nov-20 12:02 AM I'm (again) thinking about going with a bigger crystal and selling my current one 05-Nov-20 12:03 AM makes sense 05-Nov-20 12:03 AM but I'm not sure I could sell it 05-Nov-20 12:05 AM just wouldn't be able to find a buyer? 05-Nov-20 12:05 AM yeah 05-Nov-20 12:05 AM from what I've seen this is a bit outside of what most want to spend on their hobby 05-Nov-20 12:06 AM Don't get me wrong, it's a very tempting thought 05-Nov-20 12:07 AM I was thinking ~700 for the complete detector (3.2% @ 662 keV), since the 1x1" would be just over a grand 05-Nov-20 12:07 AM So like new radio prices, and for a built detector 05-Nov-20 12:08 AM very high frequency radio wave reciever 05-Nov-20 12:08 AM lol 05-Nov-20 12:08 AM I might be trying to break the unofficial world record for highest frequency amateur radio contact 05-Nov-20 12:11 AM communicating via gamma ray bursts? 05-Nov-20 12:12 AM not quite that intense 05-Nov-20 12:13 AM what's the current record? my guesstimation is ~100 GHz? 05-Nov-20 12:16 AM somewhere around 240 EHz 05-Nov-20 12:16 AM I think 05-Nov-20 12:20 AM X-ray tube modulator? 05-Nov-20 12:20 AM lead shutter over gamma source 05-Nov-20 12:20 AM cw only 05-Nov-20 12:21 AM I see 05-Nov-20 12:21 AM but at that point 05-Nov-20 12:21 AM is that amateur radio anymore? 05-Nov-20 12:21 AM or is that amateur radiation 05-Nov-20 12:22 AM There was an article published at one point in some radio magazine with a record using maybe Co60 05-Nov-20 12:22 AM So I need to pass that 05-Nov-20 12:22 AM have fun 05-Nov-20 12:22 AM Thanks 05-Nov-20 12:30 AM Gamma morse lamp? 05-Nov-20 12:30 AM sounds like a crazy project 05-Nov-20 12:33 AM yep, that's the plan 05-Nov-20 12:34 AM if there isn't a distance requirement it would be a slightly more reasonable idea than it initially seemed 05-Nov-20 12:34 AM tabletop distance with check sources could be a way to do more than one setup quickly without needing a whole lot of shielding 05-Nov-20 01:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190221_152903-1C8F0.jpg 05-Nov-20 01:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20190221_152958-9D714.jpg 05-Nov-20 01:08 AM has anybody got the manual for this detector? 05-Nov-20 02:47 AM Heh... If I had an x-ray tube with a control grid I would be very interested in modulating it with some music 05-Nov-20 03:01 AM You're listening to X-RAY FM 05-Nov-20 03:01 AM Music you literally can feel 05-Nov-20 03:01 AM "Yo! Get a load of these sick beats" 05-Nov-20 03:01 AM albeit hours, weeks or even years later 05-Nov-20 03:02 AM Falls sick from acute radiation sickness 05-Nov-20 03:02 AM Down with the radiation sickness 05-Nov-20 03:03 AM @iz we totally need to do this 05-Nov-20 03:36 AM ooohh yea 05-Nov-20 03:49 AM oh my god 05-Nov-20 03:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-24320.png 05-Nov-20 03:49 AM it is so big 05-Nov-20 03:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D9BB5.png 05-Nov-20 03:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2C9F3.png 05-Nov-20 03:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5902C.png 05-Nov-20 05:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B9A0D.png 05-Nov-20 05:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-95983.png 05-Nov-20 05:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CD652.png 05-Nov-20 10:29 AM hrm, looks like this thing only outputs counting pulses, no spectroscopic data 05-Nov-20 10:30 AM so this is as a good as a geiger counter then? 05-Nov-20 10:30 AM or X-ray intensity counting? 05-Nov-20 10:34 AM yeah basically as good as a geiger 05-Nov-20 10:34 AM of which I have plenty 05-Nov-20 10:34 AM I own one of those. 05-Nov-20 10:34 AM I'll just redo the amplifier PCB 05-Nov-20 10:34 AM I own one of those. @rdpierce do you have a pinout? I have two pins I don't know the function fo 05-Nov-20 10:35 AM I reverse engineered the protocol. 05-Nov-20 10:35 AM but isn't that just probe ID? 05-Nov-20 10:36 AM It’s complicated.... there is a serial EEPROM. 05-Nov-20 10:36 AM But there are additional pins for inhibiting count. 05-Nov-20 10:36 AM This is part of a detector system that uses a time to count mechanism to eliminate need for error prone dead time correction. 05-Nov-20 10:37 AM from what I figured there are two wires to the eeprom, right? 05-Nov-20 10:37 AM so the other two are count inhibit? 05-Nov-20 10:37 AM With a GM tube, it shuts off HV. Then it turns on HV and counts time until next count. 05-Nov-20 10:37 AM That gets around saturation. Allegedly. They claim they can count up to 10,000 R/h on the low range tube. 05-Nov-20 10:37 AM I need to check. The EEPROM has an enable and a clock, and the data output pin which is shared with the count output pin. 05-Nov-20 10:37 AM I have a manual for this probe somewhere. It’s supposedly an SCA. 05-Nov-20 10:39 AM that would make sense 05-Nov-20 10:39 AM but eh, I'll redo the whole PCB, I want them spectroscopic infos! 05-Nov-20 10:41 AM Should be calibrated for x-ray from transuranic elements. It’s US Air Force designed for surveying after a Broken Arrow incident. 05-Nov-20 10:41 AM I also have the data format for the EEPROM but it’s pretty boring. The help screens on the meter itself, which I’ve also reverse engineered, describe the data format. I’ve been able to use an Arduino to dump the EEPROM. 05-Nov-20 10:43 AM it had a sticker on it, cps per mr/h Cs137 :v 05-Nov-20 10:47 AM For a while I was pretty hard core into reverse engineering this system. I ran into some trouble because someone supposedly sold me an alpha + beta scint that was supposedly phoswich, but it really was just an alpha only scint, and I discovered incompatible hardware changes were likely made in the meter that mean the old Air Force surplus meters I have cannot be used with the Alpha Beta scint because the probe cable only recognizes one pin as an input to the meter for counting, but the hardware for the ABP uses two, to let the meter distinguish separate alpha and beta counts. 05-Nov-20 10:47 AM I’ve got several of the original meter, a beta probe frisker (that apparently subtracts ambient gamma by subtracting the gamma count times a scaling factor measured in the base meter), that x-ray probe, an alpha scint, and a different design alpha scint mislabeled as alpha + beta. 05-Nov-20 10:50 AM neat 05-Nov-20 10:53 AM I need to dig through my docs 05-Nov-20 10:54 AM Safe yourself the effort, if it supplies only counts I don't need it anyways 05-Nov-20 11:00 AM That’s all it does, sorry. I can get you the pinout info you need to power it and test it in counts mode if that would help. 05-Nov-20 11:03 AM already done that 05-Nov-20 11:03 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_7852-CC1CB.JPG 05-Nov-20 11:05 AM Well ok then. 05-Nov-20 11:53 AM oh interesting 05-Nov-20 11:53 AM what are those two canned guys on the pcb near the quad nand? 05-Nov-20 11:53 AM ooh there's another board 05-Nov-20 11:53 AM squints 05-Nov-20 11:53 AM i've never seen a little end-on pmt on that base before, i love it 05-Nov-20 11:59 AM hehe 05-Nov-20 11:59 AM it's like one of those big 2" 14 pin ones, but smaller 05-Nov-20 11:59 AM here's a better pic of the PCBs 05-Nov-20 11:59 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_7838-7321E.JPG 05-Nov-20 11:59 AM it's a bit funny, the PMT is held at negative HV, and so is the shield around it 05-Nov-20 12:12 PM There is a lot of digital logic in these. I haven’t reverse engineered this particular probe. 05-Nov-20 12:13 PM SCA would make sense 05-Nov-20 12:13 PM It’s multiplexing the EEPROM output with the amp output so they can share a single pin back to the counter. 05-Nov-20 12:13 PM There’s no question it is an SCA. That’s what it says in the docs. 05-Nov-20 12:13 PM dual comparator, some nands and some tri state bus buffers 05-Nov-20 12:15 PM They also have to gate the signal because they are doing time till count. 05-Nov-20 12:15 PM are they doing that in the probe or the readout? 05-Nov-20 12:16 PM In the probe. 05-Nov-20 12:16 PM You can see it on a logic analyzer. 05-Nov-20 12:16 PM 'cause on the violet wire I just get one 1 µs TTL low per detection 05-Nov-20 12:16 PM The probe fires a pulse. 05-Nov-20 12:16 PM The readout device shuts down the probe. 05-Nov-20 12:16 PM The readout device enables the probe. 05-Nov-20 12:16 PM It pulses again. It gets shut down. 05-Nov-20 12:17 PM but why 05-Nov-20 12:17 PM was this original unit coupled with a second detector? 05-Nov-20 12:17 PM If the probe enables and there’s an immediate pulse, it’s considered a pileup and the whole thing shuts down. 05-Nov-20 12:17 PM wonder if it was a compton coincidence deal 05-Nov-20 12:17 PM No, 05-Nov-20 12:17 PM ah 05-Nov-20 12:18 PM This is a weird design. It was primarily done for GM tubes that have dead time. 05-Nov-20 12:18 PM Higher dose rates get under counted. 05-Nov-20 12:18 PM The way it works is it gates open the probe and starts a high accuracy timer. Then a pulse happens. The probe is gated shut down. In the GM case, they turn off the HV 05-Nov-20 12:18 PM They do software statistical analysis. 05-Nov-20 12:18 PM If on average, if I open the gate, and it takes X ms for a pulse, then the count rate must be Y counts per second. 05-Nov-20 12:21 PM isn't that slower than just... using the scintillator like normal people do 05-Nov-20 12:21 PM do pileup like normal people do 05-Nov-20 12:22 PM Some counters count all pulses per unit time and then apply a correction factor to account for dead time. But this means you must calibrate the tube with a very high level source to determine dead time. This is a property of the tube, and it’s a source of error. 05-Nov-20 12:22 PM Time to count method means dead time is never a factor. 05-Nov-20 12:22 PM CaF2Eu's decay time is 940ns, that definitely seems rather high 05-Nov-20 12:22 PM So you don’t have to experimentally correct for it. 05-Nov-20 12:22 PM NaI's like 240ns? 05-Nov-20 12:23 PM Keep in mind this was designed for G-M tubes that have on the order of 100 us dead times. 05-Nov-20 12:23 PM The counter hardware and software is based around a timer chip. The gate opens, the timer counts microseconds or half microseconds depending on the clock crystal, and a pulse happens. 05-Nov-20 12:23 PM Saints were strapped on to this in a square peg round hole manner. They didn’t want to build completely different circuitry for scint probes, so they kept the same general approach even though a scint has low dead time. 05-Nov-20 12:23 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-A1A9B.jpg 05-Nov-20 12:23 PM This is the digital side of an alpha scint that connects to the same survey meter. 05-Nov-20 12:23 PM Pin 7 is the output to the meter. 05-Nov-20 12:23 PM Pin 6 is the chip select for the serial EEPROM. 05-Nov-20 12:23 PM When 6 is high, then Data Out on the EEPROM is inverted and connected to 7. 05-Nov-20 12:23 PM Pin 3 is the clock for the EEPROM. 05-Nov-20 12:23 PM Pin 5 is the Data In. 05-Nov-20 12:23 PM Pin 4 is used for gating the output. 05-Nov-20 12:23 PM Normally Pin 6 is low, meaning the probe is in count mode, not EEPROM read/write mode. 05-Nov-20 12:23 PM The probe holds Pin 7 high until a pulse happens. Then it goes low. 05-Nov-20 12:23 PM Pin 4 is normally low. After the pulse, it goes high, which blocks any pulses by forcing the output pin 7 high. 05-Nov-20 12:23 PM Pin 4 the goes low, the timer starts, and when Pin 7 goes low the timer stops and pin 4 goes high, blocking further pulses. 05-Nov-20 12:23 PM I have a logic analyzer trace of all this. 05-Nov-20 12:23 PM To be clear, Pins 3,4,5,6 are 5V logic outputs to the probe. Based on reverse engineering I’ve done of the base unit, they are always driven either high or low. They aren’t buffered / multiplexed in the first generation unit. Pin 7 is strictly an input to the base unit; it can’t be driven by the base unit. 05-Nov-20 12:23 PM There’s a pull-up for Pin 7 in the base unit. 05-Nov-20 12:23 PM Pin 1 is +5V Vcc and Pin 2 is Gnd 05-Nov-20 02:16 PM mhhh gore 05-Nov-20 02:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/High_resolution_crystal_sensitivity_for_hu-1D89E.pdf 05-Nov-20 03:41 PM Interesting North Korean "Portable Radioactive Minerals Detector" advertised by the "Mirae Science and Technology Exchange Agency" on page 27 of Januarys issue of Foreign Trade (their outward facing trade periodical) https://kcnawatch.org/wp-content/uploads/sites/5/2020/04/foreign-trade-2020-01-01.pdf 05-Nov-20 03:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screen_Shot_2020-11-06_at_00.34.39-5112A.png 05-Nov-20 03:47 PM i like this image devoid of context (from @GigaSquirrel 's link, which actually makes me want to go and play around with my yellowed/gross NaI crystals now..) 05-Nov-20 03:47 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1604619681_20201105-151121-7159C.png 05-Nov-20 06:08 PM @GigaSquirrel 725GHz Is the current amateur record. Highest recognized band is 241GHz. (speaking to the back log) And X-Ray QSO's have been done decades ago. 05-Nov-20 06:15 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1A9BB.png 05-Nov-20 06:16 PM Damn. 05-Nov-20 06:17 PM That is really cool! Thanks for tracking that down 05-Nov-20 06:17 PM I wonder if you could set up a simple stepper actuated system using check sources for that 05-Nov-20 06:17 PM 12cm is probably not that hard to beat 05-Nov-20 06:19 PM distance isn't what I'm going for 05-Nov-20 06:19 PM but 12cm would be increadibly easy to beat 05-Nov-20 06:29 PM yeah I was just thinking about the size of source necessary to surpass their setup's capabilities with whatever source you end up planning on 05-Nov-20 07:04 PM @iz so totally need to do this 05-Nov-20 07:04 PM let's get radioactive, fren 05-Nov-20 07:55 PM oh yeah that's going into my list of things to do 05-Nov-20 07:55 PM LOL 05-Nov-20 08:19 PM Replace the source with Co-60 and you can beat that record. 05-Nov-20 08:22 PM Why stop there 05-Nov-20 08:23 PM What can you get a hold of more energetic than 1.33 MeV? 05-Nov-20 08:23 PM Remember where I work 05-Nov-20 08:23 PM Ok you have a research reactor.... 05-Nov-20 08:23 PM What’s higher energy that can be produced and has a long enough half life to be useful? 05-Nov-20 08:25 PM Na24 05-Nov-20 08:25 PM I’m also thinking about the potential of a QSO with a particle accelerator. (Surprise particle accelerator?) 05-Nov-20 08:27 PM That would be a time 05-Nov-20 08:27 PM But I think you would have a problem at most particle accelerator labs to do it. 05-Nov-20 08:28 PM Yeah, and I think you’d need two? 05-Nov-20 08:28 PM That’s exactly what I was thinking. 05-Nov-20 08:28 PM Most aren’t configured like that. 05-Nov-20 08:28 PM Maybe a beam on beam linac. 05-Nov-20 08:29 PM woah that would be one expensive QSO 05-Nov-20 08:29 PM but then again many hams have antenna farms with all sorts of beam antennas, etc 05-Nov-20 08:31 PM Argonne has a tandem linac. 05-Nov-20 08:31 PM I wonder if they would be willing to modulate each beam with a pair of CW keys. 05-Nov-20 11:46 PM https://www.ebay.com/itm/114501637704 A nice demonstration of how easily anthracene sublimates 05-Nov-20 11:46 PM yo btw @rdpierce do you have a website or something? I want to post the detector teardown on my website and would like to reference your reverse engineering efforts 05-Nov-20 11:46 PM ...I found your blog, but it looks like there's nothing on that topic on there 06-Nov-20 01:38 AM I heard back from the scintillator guys, the Be window is 0.2 mm thick and they can't say anything about the vacuum compatibility of their stuff. @qualia @Addison-110m 06-Nov-20 01:38 AM that's about the half value layer for 3 keV 06-Nov-20 07:35 AM No website other than my blog. I haven’t done much blogging lately. Also I’m hesitant to blog about that work in particular. The company that makes this is still in business and might take offense. 06-Nov-20 07:49 AM ok ^^ 06-Nov-20 08:49 AM Please, no more SURPRISE ACCELERATORS. I’m not sure my heart could handle it and I’ve already used one of my three allotted rages for the month. 06-Nov-20 08:59 AM ships a random CRT to @funranium 06-Nov-20 10:45 AM it might rain in the bay tonight.. if only we ever got any surprise accelerator clouds around here 06-Nov-20 10:47 AM I don't understand that reference 06-Nov-20 11:04 AM this looks weirdly inapropriate 06-Nov-20 11:04 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201106_200234-BBD17.jpg 06-Nov-20 11:23 AM also apparently borax just sinks in paraffin 06-Nov-20 11:23 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201106_202300-9028A.jpg 06-Nov-20 11:23 AM not sure what I expected 06-Nov-20 11:24 AM hm 06-Nov-20 11:24 AM oops 06-Nov-20 11:24 AM sorry for the potentially bad info then 06-Nov-20 11:24 AM :D 06-Nov-20 11:46 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-AC66D.png 06-Nov-20 12:18 PM Wonder if boric acid would have worked better 06-Nov-20 12:18 PM Or if there’s just a better way to disperse it 06-Nov-20 12:19 PM I'll try boric acid when I do the second cast on my moderator 06-Nov-20 12:19 PM I guess pressing the paraffin and borax would work better 06-Nov-20 12:19 PM pressing slash sintering 06-Nov-20 12:25 PM RIP SMRs, hardly knew ye. https://www.sciencemag.org/news/2020/11/several-us-utilities-back-out-deal-build-novel-nuclear-power-plant 06-Nov-20 12:33 PM @GigaSquirrel thunderclouds are accelerators! :D https://www.nature.com/articles/s42005-019-0168-y 06-Nov-20 12:33 PM Looks like the maximum utilities were willing to pay is $55/MWh. that seems high to me... CALISO prices are usually $30/MWh. 06-Nov-20 12:33 PM ohh, right 06-Nov-20 12:33 PM stick your spectrometer out and see if you can see some EMI 511 keV 06-Nov-20 12:36 PM one thing that's got me very excited about me likely moving to the pacific northwest is that i'll no longer be in a desert, and can actually go stormchasing more than two or three times a year tops >.> 06-Nov-20 12:37 PM even more of a reason to come to europe 06-Nov-20 01:10 PM https://gigabecquerel.wordpress.com/2020/11/06/teardown-and-reverse-engineering-of-an-xp-100-caf2eu-scintillator/ 06-Nov-20 01:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201106_222300-019D0.jpg 06-Nov-20 01:43 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201106_224026_417-06C3A.jpg 06-Nov-20 01:43 PM cooling speedrun 06-Nov-20 02:10 PM looks like a paint can of LN2 06-Nov-20 02:10 PM looks like a bad phone cam 06-Nov-20 02:35 PM dang I hate when it shrinks in the cold 06-Nov-20 02:35 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-28672.png 06-Nov-20 02:35 PM => drill more holes, pour more paraffin, rinse and repeat 06-Nov-20 02:53 PM hmm well 06-Nov-20 02:53 PM the borax did sink to the bottom 06-Nov-20 02:53 PM but it was still completley encased in paraffin 06-Nov-20 02:53 PM from the outside I can't tell a difference 06-Nov-20 02:53 PM so I guess it actually worked, it just isn't homogenious 06-Nov-20 02:53 PM a homogenious block can only be done with one exact concentration 06-Nov-20 02:53 PM guess I know what I'll do tomorrow g 06-Nov-20 02:53 PM good thing I bought like... 3 kg of borax 06-Nov-20 03:20 PM also I suppose I should color them in some way to not confuse them with regular paraffin 06-Nov-20 03:20 PM ...crayons to the rescue! 06-Nov-20 05:08 PM What are you using as a neutron source? Is your fusor back online? 06-Nov-20 11:50 PM not yet 06-Nov-20 11:50 PM but I'd rather have the shielding before the source ^^ 06-Nov-20 11:50 PM also I wanted to see if I can see the boron neutron capture gamma from natural neutrons 07-Nov-20 03:55 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201107_123537-76836.jpg 07-Nov-20 03:55 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201107_124133-66B8D.jpg 07-Nov-20 03:55 AM yay first prototype is ready to be soldered 07-Nov-20 06:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201107_153729-07640.jpg 07-Nov-20 08:54 AM https://twitter.com/GigaBecquerel/status/1325119334012903426 07-Nov-20 02:45 PM paraffin wax can nicely be colored with crayons 07-Nov-20 02:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_7949-3CFF3.JPG 07-Nov-20 02:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_7950-B4E7C.JPG 07-Nov-20 02:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_7964-C390A.JPG 07-Nov-20 02:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_7965-12DB9.JPG 07-Nov-20 02:45 PM you can nicely see the separation lines and where I didn't mix it well enough :v 07-Nov-20 02:45 PM I dipped them again in molten paraffin to fix the borax, that seemd to work well 08-Nov-20 01:05 AM https://www.youtube.com/watch?v=RwHAQSKub7A 08-Nov-20 01:16 AM "With a remarkable ability to stay airborne" 08-Nov-20 07:18 AM https://gigabecquerel.wordpress.com/2020/11/08/red-pitaya-mca-part-2/ 09-Nov-20 11:18 AM Is it still the case that every MCA (sound card or hardware) is still windows only? 09-Nov-20 11:27 AM I'm running just linux 09-Nov-20 11:27 AM no idea about the sound card stuff, but the pitaya and interspet work perfectly on mint 09-Nov-20 11:27 AM the pitayas GUI is in browser, so it really doesn't matter 09-Nov-20 11:27 AM works in everything 09-Nov-20 11:34 AM ah, cool 09-Nov-20 11:43 AM I've used windows 10 for long enough to switch to linux 10-Nov-20 08:42 PM @Addison-110m hah it’s Tim Koeth because of course it is. He’s such a nerd in the best way. I want to meet him. 10-Nov-20 08:42 PM Neutrino QSO is going to give you unbeatable accelerator QSO. 11-Nov-20 09:14 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_8038-50732.JPG 11-Nov-20 09:14 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_8029-5F8D5.JPG 11-Nov-20 09:14 AM https://github.com/ozel/DIY_particle_detector/wiki I built the cern BPW34 detector! 11-Nov-20 10:28 AM Nice! 11-Nov-20 10:31 AM next attempt will be the alpha detector variant 11-Nov-20 10:31 AM I think I'll machine a chamber for that 11-Nov-20 01:29 PM cute! :D 11-Nov-20 01:43 PM :3 11-Nov-20 08:58 PM Beta decay question.... when tritium beta decays, is it accompanied by a pair of gammas? 11-Nov-20 09:08 PM I’m trying to understand what kind of equipment is involved in radio-HPLC. 11-Nov-20 09:08 PM Actually I might have answered my question.... I take it some type of liquid scintillator cocktail is mixed in, and the cell is sandwiched between a pair of PMTs? And scint is the liquid itself? 11-Nov-20 11:06 PM No, Tritium has no gammas 11-Nov-20 11:09 PM Wellllllllll, you can get some very wussy brehms x-ray. But if there's a enough tritium around for your very bad efficiency detector to see the 1:1000000 photons, you're in very deep trouble. 11-Nov-20 11:09 PM SEE ALSO: every decomposing titanium tritide source contamination incident 12-Nov-20 12:42 AM Yeah, basically 12-Nov-20 12:42 AM The scintillator (often PPO) is dissolved in a solvent (anything toluene to pseudocumene to diisopropylnaphthalene) 12-Nov-20 12:42 AM This is just general liquid scintillation counting, solvents for hplc cocktails are going to be a bit different 12-Nov-20 03:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2020-11-12_12-15-26-8B3FB.jpg 12-Nov-20 03:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2020-11-12_12-15-28-692F2.jpg 12-Nov-20 03:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2020-11-12_12-15-28_2-71A89.jpg 12-Nov-20 03:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2020-11-12_12-15-29-71AB9.jpg 12-Nov-20 03:17 AM still need to solder and test and all, but man I love the look 12-Nov-20 03:34 AM @GigaSquirrel that's a nice looking case! 12-Nov-20 03:34 AM also it took me a while to realize that the faceplates were also PCB material, nice! 12-Nov-20 03:35 AM thanks :3 12-Nov-20 10:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-359E9.png 12-Nov-20 10:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-EA36A.png 12-Nov-20 10:02 AM power button with amber LED as requested by @Addison-110m 12-Nov-20 10:02 AM I like where this is going. 12-Nov-20 10:02 AM Looks very good 12-Nov-20 10:02 AM Also the hv pot, yessssss 12-Nov-20 10:03 AM now I have to measure intrinsic resolution and whatnot, but man am I excited about doing some mobile gammaspec 12-Nov-20 10:03 AM I have one somewhat radioactive spot on a field near me 12-Nov-20 10:03 AM digging up some stones revealed a bit of radium on the HPGe 12-Nov-20 10:03 AM but now I can go there and actually measure it! 12-Nov-20 11:21 AM That looks nice. 12-Nov-20 11:24 AM Thanks! 12-Nov-20 11:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-88D7D.jpg 12-Nov-20 11:28 AM Glad I’ve got access to XRF. 12-Nov-20 11:28 AM That shaft was bent due to a hammer blow during demilitarization. 12-Nov-20 11:28 AM It’s showing up as O-6 tool steel, although with a bit more sulphur than allowed. 12-Nov-20 11:28 AM Soviet Fialka encryption machine. 12-Nov-20 11:31 AM does it actually matter what steel it is, apart from stuff like "hardened" etc? 12-Nov-20 11:31 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-BCEA3.jpg 12-Nov-20 11:31 AM Well I want the replacement I’m fabricating to have similar properties. 12-Nov-20 11:31 AM What’s good is this is a tool steel, and drill rods are commonly available and made out of tool steel. Drill rods are made in any conceivable size (because a machinist typically grinds them into drill bits) so I’m probably not going to have a problem finding a match for the diameter. 12-Nov-20 01:10 PM https://twitter.com/GovNuclear/status/1326138342342332419 12-Nov-20 01:10 PM https://twitter.com/Foone/status/1326991670877949952?s=20 12-Nov-20 01:29 PM oh boi my microfocus x-ray tube arrived 12-Nov-20 01:29 PM time to play, "is it broken" 12-Nov-20 01:30 PM oh. 12-Nov-20 01:30 PM my BGA inspection machine needs an upgrade 12-Nov-20 01:34 PM We’ve got a pair of x-ray cabinets with microfocus tubes. One 50 kV, one 100 kV. Intention is for reverse engineering electronics. 12-Nov-20 01:35 PM this one is 5um I want to see if you can use parallax shift to isolate layers in pcb 12-Nov-20 01:37 PM Where are you located? 12-Nov-20 01:37 PM That would be very interesting if you could. I think I have a pair of 12 layer PCBs, back to back. 12-Nov-20 01:37 PM Saturn V LVDC. I’ve been wanting to reverse engineer it. 12-Nov-20 01:42 PM oh cool! I am in the golden state 12-Nov-20 01:42 PM i probably wont get around to this project for a while though, I need to get some real work done first 12-Nov-20 11:24 PM sigh 12-Nov-20 11:24 PM I wanted to take an over night spectrum, and apparently forgot to change the default 1800s setting 12-Nov-20 11:24 PM got up and tadaa 12-Nov-20 11:24 PM barely a spectrum 13-Nov-20 12:35 AM Rip 13-Nov-20 04:02 AM daaaang 13-Nov-20 04:02 AM once it's all in a case and not drifting everywhere 13-Nov-20 04:02 AM it shows its actual resolution 13-Nov-20 04:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-87CDE.png 13-Nov-20 04:02 AM 3.11%! 13-Nov-20 06:32 AM How many channels does your Red Pitaya box have? 13-Nov-20 06:51 AM it only does 16k, because it just takes the 14 bit adc reading literaly 13-Nov-20 06:51 AM I wish it would average to 4 k, but the software doesn't allow that and I'm too dumb to code 13-Nov-20 08:46 AM Very nice 14-Nov-20 01:26 AM Guys, I need your help! 14-Nov-20 01:26 AM I have this spectrum of my fukushima soil sample 14-Nov-20 01:26 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-39FF3.png 14-Nov-20 01:26 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CFC4C.png 14-Nov-20 01:26 AM and I'm having troubles identifying a few peaks 14-Nov-20 01:26 AM Blie and dark green are Cs137 and 134, that's not a problem 14-Nov-20 01:26 AM but on the left side there's a few things I can't find 14-Nov-20 01:26 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A9DEE.png 14-Nov-20 01:26 AM Blue is the 32 keV x-ray from cesium, but there's something to the left of it (bright green) and something at ~82 keV 14-Nov-20 01:26 AM the spectrum was taken with my LaBr3:Ce and without any lead shielding 14-Nov-20 01:26 AM the detector is made from aluminium around the scintillator and stainless steel around the PMT, sitting on wood 14-Nov-20 01:26 AM the ~27 keV peak might be some x-rays from ??? and I accept that but I have absolutely no idea about the 82 keV 14-Nov-20 01:42 AM alsoalso I looked at some old spectra from the HPGe and the 82 keV peak doesn't show there 14-Nov-20 01:42 AM and! 14-Nov-20 01:42 AM even weirder 14-Nov-20 01:42 AM in my older spectra I can't see that peak 14-Nov-20 01:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/file-3E287.png 14-Nov-20 01:42 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/file-798CE.png 14-Nov-20 01:42 AM lemme measure without the Cs and see if I still get that peak 14-Nov-20 02:01 AM Could it be Compton scattering that is broadening out the 32 keV signal a little into lower energies? 14-Nov-20 02:02 AM no, compton scattering gives that U-shaped continua 14-Nov-20 02:02 AM 2 is the compton peak, 3 the backscatter peak 14-Nov-20 02:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/1602-AC034.png 14-Nov-20 02:18 AM NORM in the environment such as Rn that might go away or change over time ? 14-Nov-20 02:18 AM Or lanthanum self-background in the scintillator? 14-Nov-20 02:18 AM Or X-ray fluorescence from some metal ? 14-Nov-20 02:25 AM Lanthanum is in the lower energy Range, might he xrf but it would have to be a very heavy metal 14-Nov-20 02:25 AM lead is around 80 but I have none here 14-Nov-20 02:25 AM also it doesn't show up in the Background spectrum 14-Nov-20 02:25 AM also also Rn would give more peaks 14-Nov-20 04:03 AM Weird. I don’t know. 14-Nov-20 04:04 AM just checked with the NaI and it looks like the peak isn't there 14-Nov-20 04:04 AM so it has to be something intrinsic in the LaBr 14-Nov-20 04:14 AM no peak with NaI 14-Nov-20 04:14 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DA4A5.png 14-Nov-20 04:14 AM next step is to put the LaBr to the NaI and see if I get that peak 14-Nov-20 04:23 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_8116-19440.JPG 14-Nov-20 04:23 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Muh7YYP-293B8.png 14-Nov-20 05:19 AM that peak also doesn't show up with the LaBr right up the NaI 14-Nov-20 05:19 AM So I am confusion 14-Nov-20 05:51 AM how do your pulses look coming out of the detector? 14-Nov-20 05:51 AM other thought -- how does the noise on your HV supply look? 14-Nov-20 05:51 AM at least for the straggling behind the cesium peak 14-Nov-20 05:53 AM pulses and noise look excelent, resolution is great 14-Nov-20 05:53 AM power supply is spec'd at 10 mVpp ripple and has a 1M / 10 nF low pass after it 14-Nov-20 06:46 AM pulses are ~100 ns rising and RC=62µs falling 14-Nov-20 06:46 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-55B58.png 14-Nov-20 06:46 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3F5EF.png 14-Nov-20 06:46 AM this really gets close to what the pitayas limit with its 125 ms/s ADC 14-Nov-20 06:55 AM it does look like you are undershooting a bit from baseline, though? try a longer timestep 14-Nov-20 06:57 AM I do get undershoot, but the pitaya doesn't really care about it 14-Nov-20 06:57 AM don't get me wrong, the spectra look perfect and the resolution is great, better than what I got with my ortec MCA 14-Nov-20 06:57 AM I just don't know where that peak comes from, it just appears when I measure this one exact sample with this one exact detector 14-Nov-20 06:57 AM it isn't in the detectors background and it doesn't appear when measuring the sample with NaI or HPGe 14-Nov-20 07:11 AM also also it looks like the peak grew over the time I had this sample? 14-Nov-20 07:11 AM it's really weird 14-Nov-20 03:42 PM Can you try same detector but Ortec MCA and see if it’s there? 14-Nov-20 03:42 PM That might help differentiate between MCA artifact, detector artifact, or really there. 14-Nov-20 03:43 PM good point 14-Nov-20 03:43 PM remind me tomorrow 14-Nov-20 06:29 PM K alpha 1 and K alpha 2 from Ba, or maybe K alpha 1 and K alpha 2 from Cs ? 14-Nov-20 06:37 PM So, what’s the best low-cost or DIY gamma spectrum option overall? Is it Theremino, sound card systems, this Red Pitaya project, or something like Gamma Spectacular? 14-Nov-20 06:50 PM I’m skeptical of sound card options. 14-Nov-20 06:50 PM which three of those are 14-Nov-20 06:50 PM Honestly though, I'd almost put the detector a step or two above the ADC section. 14-Nov-20 06:55 PM Is the Red Pitaya effectively sampling repeatedly and acting like a sound card, or are there peak detection, sample and hold, discriminators, etc. like a more traditional ADC system? 14-Nov-20 06:55 PM My understanding is that computer sound card systems have issues with aliasing and other artifacts, they can’t accurately compute dead time for quantitative measurements, etc. 14-Nov-20 06:55 PM Now I’m wondering if physics is moving towards DSP solutions, if these get around that, etc. and how Red Pitaya compares. 14-Nov-20 07:00 PM speaking of MCA's thoughts on this https://www.ebay.com/itm/Ortec-MicroNomad-MCA-Multi-Channel-Analyzer/114336273375? 15-Nov-20 01:01 AM So, what’s the best low-cost or DIY gamma spectrum option overall? Is it Theremino, sound card systems, this Red Pitaya project, or something like Gamma Spectacular? @a_quiet_scientist Sound card, theremino, gamma spectacular (and Becqmoni) are all sound card. It's definitely the cheapest way to get a spectrum, but you'll just be able to identify isotopes, not activity etc. With a soundcard you can't get the max. resolution out of your detector, but then again it's really cheap 15-Nov-20 01:01 AM next cheapest option would be a NIM bin and the EPICS stuff like @rdpierce is using it, he can tell you a lot more about that 15-Nov-20 01:01 AM Is the Red Pitaya effectively sampling repeatedly and acting like a sound card, or are there peak detection, sample and hold, discriminators, etc. like a more traditional ADC system? @rdpierce keep in mind I'm not a software guy and I'm just using something I found on the internet, but it looks like it's doing sample and hold in digital. 15-Nov-20 01:01 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-83E0E.png 15-Nov-20 01:01 AM Now I’m wondering if physics is moving towards DSP solutions, if these get around that, etc. and how Red Pitaya compares. @rdpierce definitely DSP. Look at this thing, a modern day MCA 15-Nov-20 01:01 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/mca527_microe_microeplus_1-AAED8.png 15-Nov-20 01:01 AM speaking of MCA's thoughts on this https://www.ebay.com/itm/Ortec-MicroNomad-MCA-Multi-Channel-Analyzer/114336273375? @Addison-110m Works, but afaik it can only talk via the big proprietary thingie (can't think of the name right now) and RS232 is just for config etc 15-Nov-20 01:19 AM The Red Pitaya is basically a fast ADC, an FPGA and an embedded Linux computer, so it offers something close to DSP performance but cheaper and more hackable and flexible. 15-Nov-20 01:20 AM yep 15-Nov-20 01:20 AM it's a great system, I love it 15-Nov-20 01:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201115_204357-6CA8C.jpg 15-Nov-20 01:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201115_204503-13851.jpg 15-Nov-20 01:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201115_220326-4CDBB.jpg 15-Nov-20 01:03 PM wow, lead is heavy 15-Nov-20 01:46 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201115_223901-C2F23.jpg 15-Nov-20 01:47 PM incredibly envious of your nicely shaped shielding blocks 15-Nov-20 01:49 PM ...until you have to move half a ton of them 15-Nov-20 01:49 PM I know, this is complaining on a high level 15-Nov-20 01:49 PM am swapping the HPGe with a NaI 15-Nov-20 01:55 PM so, i've been thinking about the thing you did with your HPGe boiloff to purge your chamber of radon daughters 15-Nov-20 01:55 PM literature seems to suggest just a plain HEPA filter will cause significant depletion of progeny, and i'm mulling over the idea of finding a small inline blower unit to use for similar purging 15-Nov-20 01:55 PM dunno if there's a better way to do this 15-Nov-20 02:02 PM I'd go with a small (quiet) aquarium air pump 15-Nov-20 02:02 PM you really need no flow, just positive pressure 15-Nov-20 02:05 PM oh that's easy then, i might actually have some pumps that could work for that already 15-Nov-20 02:05 PM that poor tritium sniffer's going to get utterly gutted for parts at this rate 15-Nov-20 02:08 PM it's sad to gut a detector, but on the other hand I guess it's a good thing that you don't need it 15-Nov-20 02:09 PM true 15-Nov-20 02:09 PM my ideal situation would be being able to just conjure up any particular sort of detector out of ambient electronic detritus anyways :D 15-Nov-20 02:11 PM ooor 15-Nov-20 02:11 PM just use the tritium detectors output for purge 15-Nov-20 02:11 PM :smortthonk: 15-Nov-20 02:11 PM HMMM 15-Nov-20 02:12 PM my ideal situation would be being able to just conjure up any particular sort of detector out of ambient electronic detritus anyways :D @qualia I can highly recommend reaching that state 15-Nov-20 02:12 PM it actually has a very angry and touchy flow-rate sensor inside it that gets very nosiy and fussy if the outlet is blocked off at all 15-Nov-20 02:12 PM 'cos i mean otherwise yeah 15-Nov-20 02:12 PM hmm 15-Nov-20 02:12 PM but like 15-Nov-20 02:12 PM flooding a lead castle doesn't take any pressure 15-Nov-20 02:12 PM it's leaky as hell 15-Nov-20 02:12 PM and afaik the monitor already has a lot of filtering inside? 15-Nov-20 02:13 PM my castle is more of a solid cylinder with a huge flat lead lid 15-Nov-20 02:13 PM haven't tested how leaky it is 15-Nov-20 02:13 PM oh right you got those pig thingies 15-Nov-20 02:13 PM but yeah, and the filter lives on the outside even 15-Nov-20 02:13 PM thought about just buying a couple more but they're (unsurprisingly) $$$ 15-Nov-20 02:14 PM cheapest hobby out there 15-Nov-20 02:15 PM those $10 NIM modules lured me in 15-Nov-20 02:15 PM random twitter friends being like 'Hey kid u want some radioactive material' 15-Nov-20 02:15 PM before you know it you're up to your toes in corona tubes and 50/93 ohm BNC cables 15-Nov-20 02:16 PM rip 15-Nov-20 02:16 PM speaking of nim 15-Nov-20 02:16 PM there's a nim bin right above the castle 15-Nov-20 02:16 PM and I prefer the look without it on there, makes the detector much more accessible 15-Nov-20 02:16 PM but I want to keep nim 15-Nov-20 02:19 PM stick it underneath? 15-Nov-20 02:19 PM can't move the bin up because there's the computer 15-Nov-20 02:19 PM stick it underneath? @qualia the castle stands on a table that stands on the floor, through a cutout in the rack 15-Nov-20 02:20 PM ooh i see 15-Nov-20 02:20 PM plus I'm like 1.9 meters tall and don't want to fiddle knobs on knee height 15-Nov-20 02:20 PM ohh but I could put the computer on the rack and move the bin up 15-Nov-20 02:23 PM that is kinda what those racks are for :D 15-Nov-20 02:23 PM reminds me i need to do some grueling reorganization too 15-Nov-20 02:24 PM no but I mean on the rack, like on top of it XD 15-Nov-20 02:26 PM >.> 15-Nov-20 02:26 PM that shit does not fly in earthquakes-land 15-Nov-20 02:26 PM but you do you i guess 15-Nov-20 02:26 PM well actually i guess it would fly, that's the problem 15-Nov-20 02:27 PM XD 15-Nov-20 02:27 PM fair 15-Nov-20 02:27 PM how it started 15-Nov-20 02:27 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3E6FB.png 15-Nov-20 02:27 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-86B70.png 15-Nov-20 02:27 PM how it's going 15-Nov-20 02:27 PM :v 15-Nov-20 02:27 PM but yeah, moving the bin really gives a lot more space 15-Nov-20 02:27 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8172F.png 15-Nov-20 02:59 PM Works, but afaik it can only talk via the big proprietary thingie (can't think of the name right now) and RS232 is just for config etc The parallel port? 15-Nov-20 03:00 PM dual port memory 15-Nov-20 03:00 PM it's ortecs own way to screw the user transmit data 15-Nov-20 03:01 PM @GigaSquirrel That jumper on the amplifier if triggering me 15-Nov-20 03:01 PM dual port memory Ah, yeah, that 15-Nov-20 03:02 PM Just terminate the ports in something if you want something on it 15-Nov-20 03:02 PM That looks like just one accidental power on away from popping the inout devices in the amp. 15-Nov-20 03:02 PM don't think I have any N terminators 15-Nov-20 03:02 PM but it's not plugged in 15-Nov-20 03:02 PM Ok 15-Nov-20 03:02 PM Get some N attenuators and terminators from the local hams? 15-Nov-20 03:02 PM That's how I seem to aquire mine 15-Nov-20 03:02 PM Like a dude bringing a box of 20 new 30dB 30W attenuators to the club 15-Nov-20 03:02 PM "Hyeeeey kids who wants soem attenuators?" 15-Nov-20 03:03 PM oh nice 15-Nov-20 03:04 PM And it was not even just once :D 15-Nov-20 03:04 PM we have a huge am radio fair here 15-Nov-20 03:04 PM with flea marked and everything 15-Nov-20 03:04 PM but guess what 15-Nov-20 03:04 PM well, I asked online for some 15-Nov-20 03:11 PM Friedschafen? (butchered spelling) 15-Nov-20 03:11 PM friedrichshafen, yes 15-Nov-20 03:11 PM And online old farts think the attenuators are made of gold? 15-Nov-20 03:11 PM But at a hamfest you buy them for 1-5eur/pcs? 15-Nov-20 03:11 PM no idea about pricing 15-Nov-20 03:11 PM I hope to make friedrichshafen one of these days 15-Nov-20 03:12 PM I'm in a small german electronics forum with many hams and just asked there 15-Nov-20 03:12 PM most are young so I guess that won't be an issue 15-Nov-20 03:16 PM Good luck! 15-Nov-20 03:16 PM Thanks 15-Nov-20 03:46 PM Friedrichshafen is like Mecca for crypto collectors. 15-Nov-20 03:46 PM Enigmas, Fialkas, NEMAs, etc. show up for sale. 15-Nov-20 03:46 PM I know of an old Fialka repair person who would tune up collectors’ Fialkas for them. 15-Nov-20 03:46 PM I’m trying to repair one, which is why I had to XRF a shaft to find a replacement. 15-Nov-20 03:46 PM @GigaSquirrel the bricks do interlock on the edges, but I take it they have to be flat on the bases? 15-Nov-20 05:58 PM I’m going to build one of those Red Pitaya systems like @GigaSquirrel 16-Nov-20 12:02 AM @GigaSquirrel the bricks do interlock on the edges, but I take it they have to be flat on the bases? @rdpierce They interlock on all sides, apart from the few with flat tops / base for top / bottom 16-Nov-20 06:17 AM Oh! 16-Nov-20 06:17 AM I'll just clean up the rack to the right and put the computer there 16-Nov-20 07:33 AM How do they interlock on the sides? 16-Nov-20 07:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201116_164639-E36D4.jpg 16-Nov-20 07:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201116_164700-76990.jpg 16-Nov-20 08:50 AM I like 16-Nov-20 08:50 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_8174-22283.JPG 16-Nov-20 09:51 AM Herringbone bricks are best bricks. 16-Nov-20 10:01 AM Zero interest in grabbing this myself and just linking this here to talk about it: https://www.ebay.com/itm/Geiger-Counter-Probe-with-Scintillation-crystal-CsJ-for-MKS-Y-dosiemter/282783337274 16-Nov-20 10:01 AM Kinda surprises me that a long distance probe like that comes with an actual telescoping fishing pole for the distance 16-Nov-20 10:01 AM Why reinvent the wheel I suppose 16-Nov-20 10:04 AM oh that's a pretty good price 16-Nov-20 10:37 AM https://twitter.com/styropyro_/status/1328404134341570561 oh no 16-Nov-20 10:41 AM oh gawd 16-Nov-20 10:41 AM he did say he won't be messing with ionizing radiation lol 16-Nov-20 10:41 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DA5C2.png 16-Nov-20 10:41 AM but honestly I hope not to see a styropyro video involving ionizing radiation anytime soon 16-Nov-20 10:43 AM oh so just PCB poisoning instead of radiation poisoning 16-Nov-20 10:43 AM ¯\_(ツ)_/¯ 16-Nov-20 10:56 AM [shudder] This would explain the tweets people attempted to forward to me. 16-Nov-20 11:14 AM I'm playing around with the pin diode detector 16-Nov-20 11:14 AM and I'm getting an underwhelming efficiency of 0.25% for Sr/Y90 16-Nov-20 11:20 AM oh god 16-Nov-20 11:20 AM that's not going to be good 16-Nov-20 11:20 AM also, rip prices for xray equipment 16-Nov-20 11:20 AM and I'm getting an underwhelming efficiency of 0.25% for Sr/Y90 wait, that's really weirdly low 16-Nov-20 11:22 AM thought the same, am kind of doubting my ratemeter, will switch to frequency counter 16-Nov-20 11:34 AM with the frequency counter I get ~1% 16-Nov-20 11:34 AM over 4pi that is 16-Nov-20 11:34 AM 0.2% for Ra226 in equilibrium 16-Nov-20 03:31 PM https://twitter.com/GigaBecquerel/status/1328478335807217664?s=19 16-Nov-20 06:31 PM https://www.unquantum.net/ 16-Nov-20 06:31 PM Opinions? 16-Nov-20 06:31 PM He mentions gamma ray acts differently than photons with double slit experiment 16-Nov-20 06:51 PM quick dive: he has been doing this for decades and nobody serious seems to have picked him up. 1. it's nonsense that either hasn't got enough traction or is just too tiresome to debunk 2. there's a conspiracy all the great physicists are in on 16-Nov-20 06:56 PM Is a photon always a photon? Is there a particular energy or wavelength where the laws of photons (or electromagnetic waves) suddenly change? I think not. 16-Nov-20 06:56 PM But the effective wavelength of a gamma ray is very very small so the double slit experiment would require a very small slit. Can such a slit actually be made from atoms? 16-Nov-20 06:56 PM And the double slit apparatus is made from perfect “opaque” material. It is assumed that the radiation just disappears if it hits it, nothing is ever transmitted and no interactions with the material. No photoelectric effect or Compton scattering or quantum tunneling or reflection or transmission or anything. Is this really valid? 16-Nov-20 07:03 PM If you can't even get one tenured prof with decades more experience to look at it seriously... 16-Nov-20 07:06 PM I feel like there's some sort of experimental flaw or something being overlooked with the whole coincidence thing 16-Nov-20 07:06 PM but I haven't found it yet 16-Nov-20 07:06 PM (or my familiarity with quantum mechanics isn't quite to the point where I can work out why that is a reasonable result) 16-Nov-20 07:13 PM I bumped into that guy at the local electronics flea market a year or so back, while digging through a cardboard box full of swagelok scrap 16-Nov-20 07:13 PM I forget how the conversation started exactly but I talked briefly about my plasma physics experiments and he followed that with his own rambling about having disproved quantum mechanics or somesuch 16-Nov-20 07:13 PM I will hand it to him, his domain is memorable enough I managed to actually remember to look it up when I got home 16-Nov-20 07:13 PM ... but i got about as far as y'all and mostly wrote it off for similar reasons 16-Nov-20 07:19 PM Surely someone else has done a similar experiment with high energy photons too? 16-Nov-20 07:19 PM is the single photon source he used even a single photon source? 16-Nov-20 07:19 PM After all, he's trying to prove photons don't exist and calling it a "single gamma-ray source" 16-Nov-20 07:30 PM How do you get a single predictable gamma ray? 16-Nov-20 08:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201112_202342-E10C5.jpg 16-Nov-20 08:44 PM It appears I have a bit of a leaky cryostat 16-Nov-20 08:44 PM Or a leaky beryllium window 16-Nov-20 08:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201114_124236-297FB.jpg 16-Nov-20 08:44 PM Time to try and pump this thing down... I think this seal off valve is made from a central piece that is pressed down on some gasket, no idea what the white powdery stuff is 16-Nov-20 09:04 PM Just powdery broken beryllium, I’m sure it’s fine 16-Nov-20 09:04 PM Is that a HPGe with a beryllium window ? 16-Nov-20 09:06 PM That's not the beryllium window end, it's a seal off valve on the back of the cryostat. It is an HPGe though 16-Nov-20 09:06 PM The window may have a tiny spot where it started to flake a bit 16-Nov-20 09:06 PM I'm not entirely sure if it has been completely punctured or not, and I'm not poking around it in case it might be good still. Will know for sure when pumping it down 16-Nov-20 09:06 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201116_230756-8ACC7.jpg 16-Nov-20 09:15 PM Aww hell. Be careful please. 16-Nov-20 09:16 PM I made a cover for it, but if I have to swap out the window, it'll be a tricky business 16-Nov-20 09:16 PM I saw the radiograph @GigaSquirrel posted some time ago on here, I hope the inside of this resembles what is shown 16-Nov-20 09:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image-E5C87.png 16-Nov-20 09:51 PM @GigaSquirrel blogged about fixing one up and pumping down the dewar and stuff, worth reading. Lovely bit of machining for the plug. 16-Nov-20 10:57 PM Yeah definitely a good read. Unfortunately this plug is the much older version for a non-portable detector. I think I might just graft on a kf flange, the leak rate should be good enough and if it needs to be pumped down, I have the equipment to do it 17-Nov-20 12:05 AM Woo more HPGes! 17-Nov-20 12:05 AM congrats @Mason_Yu 17-Nov-20 02:13 AM mike kan has a lot to say about the unquantum stuff 17-Nov-20 02:13 AM http://www.tinkerhack.com/ 17-Nov-20 02:13 AM he believes the experimental process is flawed 17-Nov-20 03:17 AM Because experiments don’t validate his theory? 17-Nov-20 03:17 AM because what he calls a beam splitter isn't one 17-Nov-20 03:17 AM like 17-Nov-20 03:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/4VfnYJvbSNzi0dO5NzO4z1N_GIj4PN9q-AjWyg9suy-3488A.png 17-Nov-20 03:17 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/q5FATk07UG8W6sl5zH7pvgnlxojHDNWtsobaDI16E3-6CE1C.png 17-Nov-20 03:17 AM this guy has never heard about scattering, partial absorption and other effects 17-Nov-20 07:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201117_155750-56299.jpg 17-Nov-20 07:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201117_155800-80AAB.jpg 17-Nov-20 07:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201117_155830-22936.jpg 17-Nov-20 07:02 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201117_155945-0A767.jpg 17-Nov-20 07:02 AM owo new detector ❤️ 17-Nov-20 07:05 AM thinks that Gigasquirrel is a furry 17-Nov-20 07:07 AM the votes are still being counted 17-Nov-20 07:07 AM Squirrel is in the name, innit? 17-Nov-20 07:07 AM is curious to know just how many furrys are here 17-Nov-20 07:08 AM to be fair the squirrel is just a bit of fun, I used to be GigaBecquerel here and someone always misread that as Squirrel for some reason, and at some point I just went with it 17-Nov-20 07:08 AM @AdamMcCombs a lot 17-Nov-20 07:08 AM I'm willing to bet that furries (and lgbtq) are close to a majority when counting active users 17-Nov-20 07:09 AM Lol whopes didn't realize I was in exit 17-Nov-20 07:09 AM *edit 17-Nov-20 07:12 AM But yeah I agree 17-Nov-20 07:12 AM I'm willing to bet that furries (and lgbtq) are close to a majority when counting active users I wonder where that stat comes from 17-Nov-20 07:12 AM from getting to know people 17-Nov-20 07:13 AM ^this 17-Nov-20 07:13 AM fair 17-Nov-20 07:14 AM like almost every person I met here and got to know better 17-Nov-20 07:15 AM I see 17-Nov-20 07:16 AM same goes for a lot of other tech / science servers 17-Nov-20 07:17 AM as such from Gigasquirrel's research we conclude that a majority of people who are into science and tech are either furries, LGBTQ+ or both 17-Nov-20 07:17 AM time to publish a paper 17-Nov-20 07:18 AM Yes 17-Nov-20 07:18 AM let's switch to #off-topic-thats-sometimes-on-topic 'cause I have some things to say 17-Nov-20 09:36 AM is curious to know just how many furrys are here Hi 17-Nov-20 10:34 AM O Detector Tree, O Detector Tree You’re so good at seeing gamma 17-Nov-20 10:34 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-2ADB6.jpg 17-Nov-20 10:37 AM ok now make a bigger one 17-Nov-20 10:40 AM I’ll inform the students that I’ll need ++ENTHUSIASM from them. Their professor will be pleased. 17-Nov-20 10:45 AM you know what's easier though? 17-Nov-20 10:45 AM making a festivus pole 17-Nov-20 11:07 AM those detectors... is that a collimator? 17-Nov-20 11:08 AM And where do they place the source to be measured? At the center of the aluminum extrusions? 17-Nov-20 11:08 AM looks like they're pointed outwards 17-Nov-20 11:08 AM Oh, yeah I guess it's sort of a gamma 360 camera thing 17-Nov-20 11:08 AM It must be fully populated by Christmas! 17-Nov-20 11:08 AM (Although I guess it would look more like a bush when every branch has a detector on it) 17-Nov-20 11:08 AM What scintillator do they use for this? 17-Nov-20 11:12 AM they look too light for collimators 17-Nov-20 11:16 AM I think they build 360 cameras with a spinning coded tungsten aperature and small high efficiency detectors with either APDs or SiPMs 17-Nov-20 11:16 AM oh dang 17-Nov-20 11:16 AM Let me try and dig up a paper... 17-Nov-20 11:17 AM I only know the pinhole camera principle 17-Nov-20 11:17 AM but ofc it has terrible efficiency 17-Nov-20 11:23 AM https://sci-hub.do/10.1016/j.nima.2019.162964 17-Nov-20 11:23 AM Here we go, finally found it 17-Nov-20 11:23 AM Gamma and neutron coded apertures! 17-Nov-20 11:23 AM ohh that's sexy 17-Nov-20 11:25 AM I’m not entirely certain what they intend to mount on this other than it’s far from complete. Odds on favor a whooooole lot of BF3 and exotic things from Saint-Gobain. 17-Nov-20 11:26 AM BF3 is for neutron detection, yes? 17-Nov-20 11:26 AM they can decorate it with red and green chemicals 17-Nov-20 11:27 AM And as for Christmas trees.... 17-Nov-20 11:27 AM https://twitter.com/theebellwether/status/1328013342024339463?s=21 17-Nov-20 11:27 AM Hmm but there is no collimator though... Unless they haven't put it on yet, so it can't be for imaging as it is 17-Nov-20 11:27 AM I suppose they can just push it around the lab as an insanely sensitive "survey meter" 17-Nov-20 11:28 AM If you pay that much for the Home Depot 12 foot skeleton, you better get multiple holidays use, right? 17-Nov-20 11:29 AM we had a 7' robot zombie 17-Nov-20 11:29 AM and dressed him up as santa for christmas 17-Nov-20 11:29 AM put him in the window by the front door 17-Nov-20 11:29 AM from the street, looked like santa 17-Nov-20 11:29 AM up close, deceased mic jagger in red 17-Nov-20 01:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201117_221425-27338.jpg 17-Nov-20 01:16 PM it werkz 17-Nov-20 02:26 PM dang, 6.6% at 662 keV 17-Nov-20 03:29 PM energy resolution? 17-Nov-20 03:30 PM yep 17-Nov-20 03:41 PM What detector? 17-Nov-20 06:59 PM hopefully just NaI 17-Nov-20 07:01 PM Ok so you have bricks with flat tops or bottoms and herringbone sides? 17-Nov-20 08:30 PM Looks like at least one of my HPGe is alive 17-Nov-20 08:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201117_223014-3F097.jpg 17-Nov-20 08:31 PM Yay! 17-Nov-20 08:31 PM What’s the source? 17-Nov-20 08:31 PM Unfortunately the shaping amp I have (Ortec 450) doesn't seem to be really designed for pulse reset preamps 17-Nov-20 08:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201117_223101-D7A4D.jpg 17-Nov-20 08:31 PM 1 uCi Cs-137 17-Nov-20 08:31 PM Whenever pulse reset occurs I get that big pulse, much longer than the inhibit signal 17-Nov-20 08:31 PM So unfortunately this can't be fed into an MCA just yet... 17-Nov-20 08:31 PM Also the depletion voltage is slightly lower than I expected 17-Nov-20 08:31 PM And leakage current/background count rate slightly higher than expected 17-Nov-20 08:31 PM The shell of the cryostat is cool to the touch, perhaps at 10°C or so near the dewar 17-Nov-20 08:31 PM Something to be expected given the shell is partially in LN2 17-Nov-20 08:31 PM That makes it difficult to know for sure if the cryostat vacuum is okay though 17-Nov-20 08:35 PM Partially but that might still be a slight bit of vacuum loss 17-Nov-20 08:35 PM Yeah maybe it's a good idea that I pump this one down too 17-Nov-20 08:35 PM But I'd like to get a spectrum first 17-Nov-20 08:35 PM @GigaSquirrel I saw that you have the same Ortec 450 amplifier, do you have any good idea on how to deal with the pulse reset pulse? 17-Nov-20 08:37 PM Certainly 17-Nov-20 08:39 PM Blue is raw preamp out, yellow is output from the 450, purple is the pulse reset inhibit signal 17-Nov-20 08:39 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201117_223836-20B9B.jpg 17-Nov-20 08:39 PM Running with no differential shaping, changing integral shaping time won't do much at all to that huge pulse 17-Nov-20 08:39 PM I'm gonna try to use the constant fraction discriminator to get rid of this, but I think it might only get rid of the small pulses... 17-Nov-20 08:39 PM Also, I can confirm this power supply is not really good enough for HPGe 17-Nov-20 08:39 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201117_224855-4AB0A.jpg 17-Nov-20 08:49 PM That seems weird 17-Nov-20 08:49 PM It takes really really long to settle 17-Nov-20 08:49 PM And of course hard to make fine adjustments 17-Nov-20 08:49 PM The sawtooth pattern clearly slows down a great deal if I sit here and wait 5 minutes with the power supply pot locked 17-Nov-20 08:49 PM So a lot of those extra counts are due to the power supply. That might be why I'm seeing more background counts than I'm expecting 17-Nov-20 09:01 PM I guess a way to go about this is to set the constant fraction discriminator value to a super low voltage so it only picks out the huge negative pulse from reset, and use the output from that as an inhibit signal to the ADC 17-Nov-20 09:25 PM If I use the differential amplifier, then I'm still getting reset pulses 17-Nov-20 09:25 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201117_232612-61EC1.jpg 17-Nov-20 09:37 PM Found a good discriminator level for the reset pulses 17-Nov-20 09:37 PM Oh good 17-Nov-20 09:37 PM Are you going to end up cutting off low energy pulses though? 17-Nov-20 09:38 PM No, it's just cutting off the big pulses. I think you can see that the blue inhibit signal from the discriminator is only there when a big pulse appears 17-Nov-20 09:38 PM This is clear if I change the trigger level on the scope 17-Nov-20 09:39 PM Hm 17-Nov-20 09:39 PM Interesting 17-Nov-20 09:40 PM Perhaps not the most conventional use of a constant fraction discriminator? 17-Nov-20 09:47 PM It's clear that the reset pulses from the preamp itself is not really long enough 17-Nov-20 09:47 PM Although I have no idea how long the ADC would actually ignore the pulse 17-Nov-20 11:08 PM Initial concept drawings for the moderator for a neutron scintillator 17-Nov-20 11:08 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DC7AF.png 17-Nov-20 11:49 PM Okay I can get a spectrum now 17-Nov-20 11:49 PM Probably will do a count over night on some really arbitrary settings for shaping time, detector bias, amplifier gain and so on 17-Nov-20 11:49 PM @Addison-110m What is the neutron scintillator in that detector? Eljen liquid scintillators? Or some Li loaded inorganic crystals? 17-Nov-20 11:55 PM 10B on ZnS(Ag) I think 17-Nov-20 11:56 PM Oh! Yeah I didn't you you could use boron in inorganic scintillators 17-Nov-20 11:56 PM But I guess in this case there is no crystal bonding at all between the B-10 and the scintillator itself 17-Nov-20 11:56 PM Are they just very well mixed? 17-Nov-20 11:57 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/ZnSAg_for_neutron_detection-14C0E.pdf 17-Nov-20 11:57 PM I'd assume so 17-Nov-20 11:57 PM they appear to just be pressed together as far as I can tell from the photos (don't have the scintillator yet) 17-Nov-20 11:59 PM First background spectrum, the two peaks are the from pulse reset 17-Nov-20 11:59 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DB92C.png 17-Nov-20 11:59 PM @GigaSquirrel Do you use the auto baseline option from the Red Pitaya MCA program? 18-Nov-20 12:01 AM feels sorta wide, but then again those aren't the pulses off the actual detector I guess 18-Nov-20 12:02 AM Yeah the peak width just depends on how quick the reset occurs, which probably doesn't happen with extreme consistency. I think it may be possible to implement inhibit with either a digital input or using the other analog in 18-Nov-20 12:03 AM Yeah, auto Baseline, and I've never worked with a reset amp, sorry 18-Nov-20 12:03 AM but congrats on the detector! 18-Nov-20 12:03 AM This is my first time too, if you can't tell already 18-Nov-20 12:04 AM :D 18-Nov-20 12:04 AM lemme get out of bed and make some coffee, then I'll join you in your adventure :D 18-Nov-20 12:06 AM Well it may be time for me to go to bed, feeling pretty tired... Maybe I'll let it count background overnight? Squeeze in a 30 minute count for a Cs-137 source before I go to bed 18-Nov-20 12:06 AM Also this is using the differential amplifier, so I actually don't expect great spectral performance here... 18-Nov-20 12:06 AM I will need to move to the EPICS controlled MCA system to have access to inhibit input on the ADC, then I can stop worrying about the reset pulses 18-Nov-20 12:21 AM Ok so you have bricks with flat tops or bottoms and herringbone sides? @rdpierce Got bricks with herringbone everywhere, got some with flat top, got some with flat bottom, got some that form a corner, and those too, with all sides, flat top, or flat bottom 18-Nov-20 12:21 AM Looks like at least one of my HPGe is alive @Mason_Yu also wow that's a giant PMT 18-Nov-20 12:22 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201111_164547-59B28.jpg 18-Nov-20 12:22 AM It's for this thing 18-Nov-20 12:22 AM oh cool 18-Nov-20 12:23 AM If I can fix both, I get to keep them 18-Nov-20 12:23 AM Why can't I ever get told that 18-Nov-20 12:23 AM The shell of the cryostat is cool to the touch, perhaps at 10°C or so near the dewar @Mason_Yu sounds like it wants to be pumped, usually you get no condensation at all, then you get condensation when cooling down (because the cryosorption stuff can't handle the gas load at first, and in the end you get condensation all the time 18-Nov-20 12:23 AM woah those are some hefty bricks 18-Nov-20 12:24 AM The crystal must be completely encapsulated in these Scionix detectors right? 18-Nov-20 12:24 AM probably? 18-Nov-20 12:24 AM check the model numbers 18-Nov-20 12:24 AM Can't find much 18-Nov-20 12:24 AM I saw one on eBay a while back 18-Nov-20 12:25 AM It takes really really long to settle @Mason_Yu which is a good thing! You don't want / need to set an exact voltage for a HPGe, as it has no internal gain like prop or pmts. get withing a few 100V of the nominal voltage and you're fine 18-Nov-20 12:25 AM I mean the ripples in the power supply take a long time to settle 18-Nov-20 12:25 AM https://scionix.nl/nomenclature-type-numbering/ 18-Nov-20 12:25 AM you've read this right? 18-Nov-20 12:25 AM yep, the crystal is completely encapsulated and can be separated from the pmt 18-Nov-20 12:27 AM Initial concept drawings for the moderator for a neutron scintillator @Addison-110m hey I know that scintillator! Also lol first I read HPGe scintillator and thought you wanted to do some coincidence / anti compton stuff... Use a Scintillator with a HPGe anti compton shield 18-Nov-20 12:27 AM Probably will do a count over night on some really arbitrary settings for shaping time, detector bias, amplifier gain and so on @Mason_Yu shaping time for a HPGe should be 6-8 µs 18-Nov-20 12:28 AM Where do you see that info? @Addison-110m 18-Nov-20 12:28 AM The type sticker 18-Nov-20 12:28 AM I can't do 6-8 us with differential amplification @GigaSquirrel 18-Nov-20 12:28 AM V135A127/5M-X-NEG 18-Nov-20 12:29 AM Ah, A=demountable, thanks, brain not working at 2:30 am anymore 18-Nov-20 12:29 AM There's still a good chance I'd find yellow goop in there though, these detectors had a rough life, trying to detect land mines in an extraordinarily muddy field 18-Nov-20 12:31 AM I can't do 6-8 us with differential amplification @GigaSquirrel @Mason_Yu so your preamp outputs differential signals? Never had to deal with that, all my stuff is single ended, and all the amps have a simple turn knob to set shaping time 18-Nov-20 12:31 AM No, I mean differential shaping amplification, like taking the differential on the signal itself 18-Nov-20 12:31 AM It's the only way I can prevent the super long and super big pulse from going out of range while still see the actual pulses unfortunately 18-Nov-20 12:33 AM There's still a good chance I'd find yellow goop in there though, these detectors had a rough life, trying to detect land mines in an extraordinarily muddy field @Mason_Yu scionix makes some very stable detectors, my NaI is from the scrapyard, where someone didn't bother pulling it out of its lead shielding and threw it into a container, the lead has some very big dents and the detector is still working fine 18-Nov-20 12:33 AM why differential pulse shaping? usually you want one differentiation / high pass and then many integrations / low pass 18-Nov-20 12:35 AM By amplifying the first derivative of the signal, I get two pulses from the reset, which I can filter out with discrimination or simple background subtraction. If I do an integral pulse shaping or no shaping at all, I'd get a super long pulse well after the reset signal and much wider than the reset signal 18-Nov-20 12:36 AM mmmh I see 18-Nov-20 12:37 AM That would not work even if I had discriminators. This maybe a problem unique to the Ortec 450 amp? Not entirely sure... 18-Nov-20 12:37 AM You can see the difference between the reset pulse and an actual pulse here 18-Nov-20 12:37 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E1A05.png 18-Nov-20 12:37 AM do you have any other amps? 18-Nov-20 12:38 AM Yes, the Canberra 9615 18-Nov-20 12:38 AM But never used it before, bought it specifically for this 18-Nov-20 12:38 AM at least my 450 has a datecode from the late 60s and has some age related issues like drift and noise 18-Nov-20 12:39 AM Yeah mine is a test unit shipped to Oak Ridge with a return date sometime in the late 60s 18-Nov-20 12:39 AM I guess they never bothered to return the unit to Ortec 18-Nov-20 12:39 AM heh 18-Nov-20 12:39 AM sorry I can't offer more help here 18-Nov-20 12:45 AM The silly things I'll do for detectors (this is running in a windows XP vm because why not) 18-Nov-20 12:45 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screen_Shot_2020-11-18_at_00.44.25-32B28.png 18-Nov-20 12:47 AM Who hasn't got an old legacy pc for some obscure hard- or software :D 18-Nov-20 12:53 AM What do you use for the size of sampling window in the Red Pitaya MCA? @GigaSquirrel 18-Nov-20 12:53 AM Assuming you had a pulse with 6 us shaping time 18-Nov-20 12:55 AM I usually set it to the shaping time, as it seems to have a similar effect 18-Nov-20 12:55 AM try 4 or 8 us for your detector 18-Nov-20 12:55 AM I only wish the wait time wasn't automatically so absurdly long and had a way to set it, not just the Slider 18-Nov-20 01:01 AM Hmm yeah changing the window size for the digital filter certainly has a great impact 18-Nov-20 01:04 AM between 1 µs and 6 µs made a difference of ~doubling the resolution for me 18-Nov-20 01:04 AM halving it? 18-Nov-20 01:04 AM making it twice as good 18-Nov-20 01:07 AM Ah also, if you want faster count rate but a larger window size, setting a min threshold of something like 100 mV helps a great deal, makes it a lot faster 18-Nov-20 01:08 AM oh interesting 18-Nov-20 01:08 AM It also looks like for a bigger window, the reset pulses gets pushed further and further 18-Nov-20 01:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-48831.png 18-Nov-20 01:09 AM damn that's a sharp peak 18-Nov-20 01:09 AM I can see on the scope that the reset pulses are not reaching 15.5 V (the amp only outputs 10V) 18-Nov-20 01:09 AM that's not volts that's channels 18-Nov-20 01:09 AM Well, it is an HPGe after all, also linear scale 18-Nov-20 01:09 AM 1 channel = 1 mV I'm pretty sure 18-Nov-20 01:10 AM you've got a 14 bit ADC in there, so 16k different possible values 18-Nov-20 01:11 AM And the input limit just happens to be 16V I guess? Hmm interesting, but yeah I agree there is no direct conversion from channel to volt, due to averaging in time 18-Nov-20 01:11 AM not calibrated to anything, and I assume you're using the pitaya in the High voltage mode, so 20V / 16k channels so ~1.25 mV/channel 18-Nov-20 01:11 AM now where the peak actually ends up depends on a lot of factors, including shaping time, sample rate and whatnot 18-Nov-20 01:13 AM I'm worried that the leakage current is too high here 18-Nov-20 01:14 AM https://www.gammaspectacular.com/phpBB3/viewtopic.php?f=15&t=851&p=4250#p4249 Dang someone actually got a SrI:Eu 18-Nov-20 01:14 AM if the case gets so cold it might not be insulated enough to cool the crystal 18-Nov-20 01:15 AM I can clearly see that the leakage current starts to increase past ~1100 V, but the operation voltage is 1500V... Either way, after I'm done with this batch of LN2, I'll probably try to pump this one down as well 18-Nov-20 01:17 AM operate it at ~1100V, it will result in less depletion but at least you have no chance of harming the crystal 18-Nov-20 01:17 AM Already am doing that 18-Nov-20 01:18 AM Oh that company sells CLYC too 18-Nov-20 01:18 AM https://www.capesym.com/clyc.html 18-Nov-20 01:18 AM Hopefully they'll be more reasonable with their pricing... 18-Nov-20 01:19 AM isn't clyc extremly expensive? 18-Nov-20 01:20 AM Yeah, like SrI... 18-Nov-20 01:20 AM What’s cool about SrI:Eu? 18-Nov-20 01:20 AM More so than SrI 18-Nov-20 01:20 AM Just really high light yield and <3% at 662 keV 18-Nov-20 01:21 AM Oh, very cool 18-Nov-20 01:21 AM And I suppose no inherent background like LaBr ends up having 18-Nov-20 01:22 AM yep 18-Nov-20 01:22 AM but very, very slow and some assymetrical peaks, it's still in very early development 18-Nov-20 01:23 AM So wait 5 years to iron out the bugs? 18-Nov-20 01:24 AM and then another 20 to make it affordable 18-Nov-20 01:24 AM Ehh, I’ve got two kidneys, can spare one 18-Nov-20 01:24 AM XD 18-Nov-20 01:24 AM there are a few high rez scintillators out there, but they all have some sort of issues 18-Nov-20 01:25 AM My hope is on somehow running into a czt detector eventually 18-Nov-20 01:26 AM LaBr is very high background, CeBr has less resolution, SrI is just weird 18-Nov-20 01:26 AM there are a few CZTs on ebay atm, but afaik they're finnicy to get running and a good resolution 18-Nov-20 01:26 AM they're weird, it's not exactly a semiconductor Ì think and behaves more like a resistor? 18-Nov-20 01:26 AM still need to get a signal out of mine... 18-Nov-20 01:28 AM Any luck yet? 18-Nov-20 01:28 AM Ah, so it does have ASIC preamps? 18-Nov-20 01:28 AM no attempts so far, asic preamps and a whole lot of epoxy 18-Nov-20 01:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-67EAA.png 18-Nov-20 01:28 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-CF54C.png 18-Nov-20 01:30 AM Fun 18-Nov-20 01:31 AM thinking about letting it soak in DCM until it reveals its secrets 18-Nov-20 01:35 AM That simultaneously makes sense buts also terrifying 18-Nov-20 01:39 AM which is why I have not done it yet 18-Nov-20 01:42 AM Why is DCM terrifying? 18-Nov-20 01:42 AM It used to be an over the counter paintstripper until about a decade a go. 18-Nov-20 01:42 AM Not health terrifying 18-Nov-20 01:43 AM Like sure I know a guy with tremors thanks to exposure to it, but his was decades of exposure to it with the machines that washed asphalt away from equipment with hot DCM and few kW's of ultrasonics. 18-Nov-20 01:43 AM Dude was splashed by it regularly and was soaked. 18-Nov-20 01:43 AM So now he can't solder SMD due to tremors. 18-Nov-20 01:45 AM terrifying because it's a ~100€ part and I have no idea what exactly will happen if I just leave it in solvent for a long time 18-Nov-20 01:45 AM ^ 18-Nov-20 01:56 AM Ah 18-Nov-20 01:56 AM The connectors might dislike the DCM the most 18-Nov-20 02:06 AM at this point I am just trying to free the crystal itself 18-Nov-20 04:19 AM on that SrI 18-Nov-20 04:19 AM The cost was $1250 plus shipping 18-Nov-20 07:20 AM I believe I have a Canberra 9615. 18-Nov-20 07:20 AM What’s your ADC? 18-Nov-20 07:20 AM Get EPICS working. 18-Nov-20 07:20 AM I know the 9615 has a special mode for dealing with reset pre-amps. 18-Nov-20 07:28 AM I have the 9635 ADC 18-Nov-20 07:28 AM Will try to do this today, just taking some spectra of various sources with the set-up I have now. 18-Nov-20 07:31 AM we wanna see spectra! 18-Nov-20 07:31 AM what rez you got? 18-Nov-20 07:53 AM I need more peaks for energy calibration 18-Nov-20 07:53 AM But right now it looks like ~1.7% at 662 keV... Really not that great 18-Nov-20 07:59 AM should be an order of magnitude lower 18-Nov-20 08:40 AM Yeah I think differentiating the signal doesn't help... Hopefully the 9615 will work better 18-Nov-20 08:40 AM But good news is I found a welding shop who will deliver my filled dewar to me a day after I drop it off to be filled 18-Nov-20 08:40 AM $61 for 30 liters, plus $15 for delivery, not bad for where I am. 18-Nov-20 08:49 AM yay 18-Nov-20 08:49 AM that's about the same I pay 18-Nov-20 08:51 AM I still need to take an Uber out to the welding shop though, so add $10 on top of that and taxes, and maybe it'll last two to three weeks? 18-Nov-20 08:51 AM I've been taking detectors in and out very often and the other detector with bad vacuum certainly consumed a lot of it, so I might only get a week and a half out of this tank 18-Nov-20 08:52 AM puuuump it 18-Nov-20 08:53 AM I'm gonna just stick a KF adaptor on there with Hysol-1C 18-Nov-20 08:53 AM 'cause if you don't it will arc over internally at some point 18-Nov-20 08:54 AM An excuse to get the drag pump working too 18-Nov-20 08:55 AM not sure if drag gets down far enough 18-Nov-20 08:55 AM Such expensive LN2 18-Nov-20 08:55 AM Cheap for your runtimes I guess 18-Nov-20 09:01 AM ln2 is why I went back to NaI 18-Nov-20 10:57 AM 'cause if you don't it will arc over internally at some point @Mason_Yu does it have a hv inhibit lead from the detector? 18-Nov-20 10:57 AM $1250 isn't nearly as bad as I expected, that's still in fancy radio prices 18-Nov-20 10:57 AM Too much for for for sure but not the multiple thousands i expected 18-Nov-20 11:00 AM Nope, as far as I can tell it may not even have a crystal temp output 18-Nov-20 11:06 AM bias shutdown or anything? 18-Nov-20 11:06 AM or is it just really old 18-Nov-20 11:10 AM Yeah it's really old 18-Nov-20 11:10 AM Only a test output. The DB9 connector carries power only 18-Nov-20 11:12 AM input, not output, right? 18-Nov-20 11:12 AM https://capescint.com/product-category/detector-assemblies/ ...dang 18-Nov-20 11:18 AM Yeah, test input 18-Nov-20 11:18 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DD86B.png 18-Nov-20 11:20 AM what's the inhibit output 18-Nov-20 11:20 AM or is that part of the preamp 18-Nov-20 11:21 AM The inhibit is for the amplifier/ADC to ignore the part when the reset preamp resets 18-Nov-20 11:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-5BCBC.png 18-Nov-20 11:22 AM all this effort just to get rid of the thermal noise of one resistor 18-Nov-20 11:23 AM Only commonly found on low energy detectors 18-Nov-20 11:24 AM and high rate 18-Nov-20 11:25 AM There's an ortec manual with at least a decent bit about transistor reset preamps that I could scan if you think it's useful 18-Nov-20 11:27 AM Yes please! And post it to #resources too if possible 18-Nov-20 11:27 AM Sure! I'll try and get to it later today when I'm in the office 18-Nov-20 11:27 AM https://capescint.com/product/macropixel-nel-14x25c-sipm-t/ 18-Nov-20 11:27 AM wow 18-Nov-20 11:31 AM yep 18-Nov-20 11:31 AM do it 18-Nov-20 11:33 AM Also, I ran across radioactivityforum.​it yesterday and wow the number of manuals they have on hand 18-Nov-20 11:35 AM yep they're a goldmine! 18-Nov-20 11:35 AM speaking of gold 18-Nov-20 11:35 AM dang, copper is expensive 18-Nov-20 11:36 AM lol 18-Nov-20 11:36 AM 2 mm copper sheet for my lead chamber would be 120€, just the sides, nothing on the top yet 18-Nov-20 11:36 AM and 2 mm is... eh 18-Nov-20 11:36 AM I've toyed with using pennies and doing shielding with a zinc layer 18-Nov-20 11:37 AM iirc tin should also work well 18-Nov-20 11:37 AM ...tin is even more expensive 18-Nov-20 11:39 AM kinda why pennies were tempting me. zinc is cheap and technically it's legal 18-Nov-20 11:41 AM at 80 keV, the range of lead xrf, zinc and copper hace basically the same mass attenuation coefficient 18-Nov-20 11:41 AM would be a great shield if it only costs you pennies to make 18-Nov-20 12:03 PM yeah, if I eventually get a detector working... 18-Nov-20 12:05 PM what's stopping you? 18-Nov-20 12:05 PM oh! 18-Nov-20 12:05 PM brass is a lot cheaper 18-Nov-20 12:11 PM Getting software stuff figured out mostly 18-Nov-20 12:11 PM Only recently getting familiar with running windows software on this computer 18-Nov-20 10:24 PM Is anyone by chance familiar with the software for calibrating eberline E600 meters? 18-Nov-20 10:24 PM @Mason_Yu didn't get a chance to scan it today, I'll try tomorrow 18-Nov-20 10:39 PM uhhhh, memory is rusty. It's been 14 years. 18-Nov-20 10:39 PM Thanks! Now I'm pretty sure the solution is just to use the Canberra 9615 ICB amplifier. It has the inhibit input needed for a reset preamp and is basically designed for this. Spent the night installing EPICS and Mark River's MCA software, along with the GUI running on IDL VM, then I discovered I'm missing the ICB cable... 18-Nov-20 10:39 PM It's bascially twelve 20 pin ribbon connectors daisy chained together, time to make my own I guess... I may not have enough ribbon cable on hand to do this though 18-Nov-20 10:43 PM If you've got a specific question @Addison-110m that might help knock gears of memory loose. At the moment, memory is conjuring the old computer in the Calibration Lab where I'm staring at it blankly. 18-Nov-20 10:52 PM Trying to figure out the default password for the software 18-Nov-20 10:54 PM 0000 or 9999 didn't work? 18-Nov-20 10:54 PM somehow no 18-Nov-20 10:54 PM it's weird and not documented anywhere 18-Nov-20 10:54 PM LMFAO 18-Nov-20 10:54 PM It's Eberline 18-Nov-20 10:54 PM cocky freaking programmer 18-Nov-20 10:56 PM Damn. Well, PROTIP, if you buy LLNL surplus E600s, they're all set to 0000 or 9999. 18-Nov-20 10:57 PM I'll keep that in mind because given that they're looking to be way more hackable than I thought it might be a cool meter to keep an eye out for 18-Nov-20 10:59 PM Fair warning, they appear way cheaper than their original asking price because they're a bit of a pain to maintain. 18-Nov-20 10:59 PM So you got your software with the meter? 18-Nov-20 10:59 PM I mean, they're SUPER versatile and I love them but I love not being responsible for their care and feeding even more. 19-Nov-20 02:59 AM I just found "good SER" in the datasheet for a PMT and I have never heard that term 19-Nov-20 02:59 AM any idea what it means? 19-Nov-20 10:05 AM Single Electron Response, looks like 19-Nov-20 10:15 AM ahh that would make sense 19-Nov-20 10:15 AM thanks! 19-Nov-20 10:41 AM https://www.researchgate.net/publication/3139669_Stabilizing_Scintillation_Detector_Systems_with_Pulsed_LEDs_a_method_to_Derive_the_LED_Temperature_from_Pulse_Height_Spectra this is a fun paper 19-Nov-20 10:41 AM I did not know LED stabilization of PMTs was a thing 19-Nov-20 10:42 AM I want a thermometer based on that 19-Nov-20 10:42 AM I DO TOO 19-Nov-20 10:42 AM I did, I am half assed working on a pmt tester based on that 19-Nov-20 10:42 AM This feels like one of those things that shouldn't work at all 19-Nov-20 10:42 AM jut pulse and see what resolution comes out 19-Nov-20 10:42 AM turns out 662 keV from NaI is an even ~25k photons 19-Nov-20 10:42 AM now if I can get an LED to output that in ~1 µs I'm happy 19-Nov-20 10:42 AM couple that to PMTs and see what gives the best phr 19-Nov-20 11:45 AM https://twitter.com/storax7662/status/1329510611147898881 19-Nov-20 12:45 PM https://gigabecquerel.wordpress.com/2020/11/19/lead-and-downgrades/ 19-Nov-20 03:34 PM TIL about the Rossi curve :D 19-Nov-20 06:18 PM @Mason_Yu you don’t need a lot of ribbon cable for ICB. 19-Nov-20 06:18 PM It’s a daisy chain bus. But you can make the cable as short as you need. 19-Nov-20 06:18 PM Yeah, the inhibit pulse from the preamp may not stop the amp from forming an ugly pulse from the reset but it should cause the ADC to ignore it, and consider everything as dead time until the amp gets back to baseline. 19-Nov-20 06:18 PM I know Mark Rivers personally and I know their detectors are all reset based. 19-Nov-20 06:18 PM They use the same ICB amp. I’m happy to reach out to him and put you in touch. 19-Nov-20 06:18 PM That amp is... interesting engineering. 19-Nov-20 06:18 PM The reason it is so wide is that its gain is a multi-turn precision pot... turned by a STEPPER MOTOR. 19-Nov-20 06:18 PM That’s not the kind of engineering you expect to see. 19-Nov-20 06:18 PM There’s an option that needs to be set to tell it you are using a reset preamp, not an RC. I believe this gets rid of the need to set Pole/Zero. 19-Nov-20 06:40 PM grecord(mbbo,"$(P)$(AMP)PTYP") { field(DESC,"Pre-amp type") field(PINI,"YES") field(ZRVL,"0") field(ZRST,"RC") field(ONVL,"1") field(ONST,"TRP") field(RVAL,"1") field(DTYP, "asynInt32") field(OUT,"@asyn($(PORT))PREAMP_TYPE") } 19-Nov-20 06:40 PM You need to set this for TRP 19-Nov-20 06:40 PM You’ll also need to take a look at this: 19-Nov-20 06:40 PM grecord(mbbo,"$(P)$(AMP)INHP") { field(DESC,"Inhibit polarity") field(PINI,"YES") field(ZRVL,"0") field(ZRST,"Positive") field(ONVL,"1") field(ONST,"Negative") field(DTYP, "asynInt32") field(OUT,"@asyn($(PORT))INHIBIT_POLARITY") } 19-Nov-20 06:50 PM C.3 OperationWithResetPreamps The Model 9615 is fully compatible with most reset type preamps. Reset preamps use an electronic circuit, as opposed to a feedback resistor to restore the preamp output back to a reference level. As a result, the reset preamp output is a succession of step functions that staircase or ramp up to an upper limit that initiates a preamp reset. Since the reset preamp signal does not have the characteristic exponential fall time as with RC preamps there is no requirement for Pole/Zero compensation. P/Z Compensation With Reset Preamps Reset Preamps do not require pole/zero compensation. When using the Model 9615 with a reset preamp, select a preamp type of TRP which automatically will reduce the Pole/Zero compensation to zero. Using the Reset Preamp Inhibit Signal The preamp reset event produces a large signal to the amplifier driving it into a severe overload condition. The Model 9615 recovers from overload events rapidly and monotonically requiring approximately two non-overload pulse widths to fully recover. Converting events during amplifier overload may produce spectral distortion and it is recommended that the ADC be gated off during this time using the preamp INHIBIT signal. The preamp INHIBIT signal width should be adjusted to encompass the full unipolar signal recovery. Please consult the Detector/Preamp Operator’s Manual for this adjustment. The INHIBIT signal from the Model 2101 Transistor Reset Preamp or Model 2008 Optical Reset Preamp is positive true. Connect this signal to the amplifier’s INHIBIT input and set the programmable Inhibit polarity to the proper level. The REJECT signal on the PUR cable from amplifier to ADC will discard pulses during the Inhibit with PUR mode either ON or OFF. 19-Nov-20 06:50 PM Overload Recovery Some preamps produce undesirable secondary effects following the preamp reset. The secondary effects may result from long time constants or non-linearities producing excessive unipolar output signal recovery time. System throughput may be compromised and in extreme cases premature baseline instability may result at high count rates. The 9615 amplifier automatically gates off the baseline restorer (BLR) for normal detector signals and preamp reset events to maintain signal precision. 19-Nov-20 06:50 PM So it looks like you will need an additional cable from the preamp to the ADC. 19-Nov-20 06:50 PM I’ve made one of these. 19-Nov-20 06:50 PM It’s a 3 pin Molex plug 19-Nov-20 06:50 PM And you need a BNC for the dead time. 19-Nov-20 06:50 PM This should account properly for dead time when the reset happens. 20-Nov-20 02:08 AM Has anyone here got data for a Tennelec 155A PMT base? 20-Nov-20 02:08 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/s-l1600-AC819.png 20-Nov-20 02:08 AM Just bought this on ebay 20-Nov-20 02:08 AM only mention that describes them I could find was some MCA manual 20-Nov-20 02:08 AM Some detector tube bases such as the Tennelec model TC155A, incorporate a built-in preamplifier which takes its power from the high voltage supply. 20-Nov-20 02:08 AM which does not make any sense at all imo 20-Nov-20 02:39 AM i think i have a base that works like that 20-Nov-20 02:40 AM wot 20-Nov-20 02:40 AM how 20-Nov-20 02:40 AM like I'd get it if it was phantom power over the signal connector 20-Nov-20 02:40 AM but from the high voltage?! 20-Nov-20 08:41 AM It’s possible it might not be a preamp. 20-Nov-20 08:41 AM Just a typical PMT base with a HV resistive divider, assorted caps for voltage stabilization, and a cap to separate the signal from the DC bias. 20-Nov-20 08:43 AM that's what I thought, too 20-Nov-20 08:43 AM we'll see once it gets here 20-Nov-20 08:43 AM There’s also a pot for focus, but that’s part of the HV divider. 20-Nov-20 08:43 AM yep 20-Nov-20 08:43 AM General Characteristics Item Description Negative input polarity, positive output polarity, 100 usec decay time, 50 ohm impedance, 4 V dynamic range, built-in preamplifier, focus electrode voltage potentiometer, for 14 pin photomultiplier 20-Nov-20 08:45 AM I have a couple NaI scints that just have single MHV plugs, and I need a splitter box to use them, and I need to use the preamp input on my SpecTech MCA. 20-Nov-20 08:45 AM Huh. 20-Nov-20 08:45 AM That makes no sense. 20-Nov-20 08:45 AM A preamp needs power. 20-Nov-20 08:46 AM LA-5485-M mentions it, but the LANL library catalog is loading slowly for me at the moment so I can’t track down the full text. 20-Nov-20 08:46 AM only thin I can imagine is phantom power on the BNC line 20-Nov-20 08:46 AM Or the HV line. 20-Nov-20 08:46 AM Resistor network then a linear regulator. 20-Nov-20 08:47 AM is that the enrichment meter paper? 20-Nov-20 08:47 AM don't think so, because then the HVPS would have to supply the complete corrent for the preamp 20-Nov-20 08:47 AM You could also use a buck converter, but I’d be terrified of something like that generating noise. 20-Nov-20 08:48 AM Yeah 20-Nov-20 08:48 AM if it takes 10 mA, which would be little for a preamp for that time, that would be 10W at 1 kV 20-Nov-20 08:48 AM read that, it just mentions it and that's it 20-Nov-20 08:53 AM I’m not sure. Let’s say you have 10 stages of resistors, each dividing 100 V. 20-Nov-20 08:53 AM Replace the last resistor with a pair, essentially allowing you to tap off 10V. 20-Nov-20 08:53 AM Then put that through a 7805 linear regulator to produce 5V to power the preamp. 20-Nov-20 08:54 AM those 10 mA or howevermuch the preamp wants still has to run through the whole divider 20-Nov-20 08:55 AM Hmmm.... 20-Nov-20 08:55 AM Well we’ll see when you dissect this. 20-Nov-20 08:55 AM yep 20-Nov-20 08:56 AM I think it more likely that parasitic power is coming off the HV side than the signal side. 20-Nov-20 08:56 AM ups guesstimates tuesday for delivery 20-Nov-20 08:56 AM no way, grabbing it off the HV just would not make any sense 20-Nov-20 08:56 AM And that does look like a seriously beefy power supply. 20-Nov-20 08:57 AM what would be a point against power through the signal? 20-Nov-20 08:57 AM less waste, easier to handle 20-Nov-20 08:57 AM Open up the PMT base and see what’s inside 20-Nov-20 08:58 AM I will, once I get it 20-Nov-20 09:00 AM I called it. 20-Nov-20 09:00 AM http://www.spectrumtechniques.com/manuals/ST400manual.pdf 20-Nov-20 09:00 AM Some detector tube bases such as the Tennelec model TC155A, incorporate a built-in preamplifier which takes its power from the high voltage supply. In this instance, the output signal from the pream- plifier must be connected to the Amp In connector on the ST400. Other types of tube bases such as the ORTEC model 276 offer both anode and preamplifier outputs. When using this configuration, we recommend using the anode signal connected to the Preamp In on the ST400. If an external preamplifier must be used, most likely it will require low voltage DC power which is not supplied from the ST400. If this power is made available, then the positive preamplifier output signal may be connected to the Amp In on the ST400 20-Nov-20 09:06 AM That's where I copied that from 20-Nov-20 09:06 AM but I still don't believe it 20-Nov-20 09:06 AM it doesn't make any sense 21-Nov-20 12:14 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201121_122948-E84AE.jpg 21-Nov-20 12:14 PM Got my hands on the two massive NaI detectors today 21-Nov-20 12:14 PM One of them does register pulses, but way too few of them. The other seems to just have a short between the cathode and anode inside the PMT 21-Nov-20 12:14 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201121_140232-E5FA9.jpg 21-Nov-20 12:14 PM Demounting this massive PMT has proven to be challenging though... The optical grease is sticky and the lip around it prevents me from sliding in some really thin shin stock under it 21-Nov-20 12:17 PM chonkers 21-Nov-20 12:17 PM how does a short between anode and cathode happen tho 21-Nov-20 12:17 PM they're so far apart 21-Nov-20 12:18 PM No idea, maybe all the dynodes collapsed on each other? 21-Nov-20 12:18 PM hmm 21-Nov-20 12:18 PM since it's dead already a teardown would be interesting 21-Nov-20 12:18 PM I've never seen a failed PMT apart from having a leak 21-Nov-20 12:18 PM also good luck on those scintis still being white 21-Nov-20 12:22 PM I can see it's a little bit yellow through the edges 21-Nov-20 12:22 PM Not too bad though 21-Nov-20 12:23 PM Oh you know what, the failure might be inside the base 21-Nov-20 12:23 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/googins1987_cleaning_NaI-297A8.pdf 21-Nov-20 12:23 PM They sort of rewire the wires from glass feedthroughs into a standard PMT mount 21-Nov-20 12:23 PM That base is sealed with epoxy and is the blue thing that sticks out of the detector assembly 21-Nov-20 12:23 PM And the anode and cathode wires are pretty close inside 21-Nov-20 12:25 PM cool 21-Nov-20 12:38 PM I can hear something rattling inside lol 21-Nov-20 12:38 PM Never a good sign 21-Nov-20 12:38 PM Looks like I might need some solvent 21-Nov-20 12:53 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201121_145244-343A2.jpg 21-Nov-20 12:53 PM Successful removal without solvents, the crystal itself is actually milky white! 21-Nov-20 12:53 PM that PMT looks like it got vented 21-Nov-20 12:53 PM Yep 21-Nov-20 12:53 PM The base is nearly completely detached from the glass 21-Nov-20 12:53 PM Probably sustained a good shock 21-Nov-20 12:53 PM This thing is so heavy that's a drop from half a meter will probably shatter the entire tube 21-Nov-20 12:55 PM F 21-Nov-20 12:55 PM but hey, teardown and a free electron multiplier 21-Nov-20 12:56 PM I might need to cut through the hard epoxy attaching the base to the glass 21-Nov-20 12:58 PM but the crystal looks pretty damn good 21-Nov-20 01:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201121_150140-1E386.jpg 21-Nov-20 01:17 PM From the base of the new PMT, I can see the cathode wire makes a bit of a bend after it exits the glass 21-Nov-20 01:17 PM That might be where the failure is 21-Nov-20 01:17 PM Unfortunately the new PMT is 15 mm shorter than the old one 21-Nov-20 01:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201121_151755-0C08D.jpg 21-Nov-20 01:19 PM can't you add more padding between the pmt and shield to compensate? 21-Nov-20 01:20 PM I will to add positive retention on the PMT, but the stem of the mu metal shield still needs to be cut short so I can mount it to a base 21-Nov-20 01:20 PM but that's an interesting mode of failure 21-Nov-20 01:22 PM Random question these photos brought to mind... Is there any reference material for what various scintillation crystals are sealed with from different manufacturers? 21-Nov-20 01:22 PM Also congrats on the giant NaI! Even with the PMT issues those are quite a score 21-Nov-20 01:23 PM not sure what you mean 21-Nov-20 01:23 PM a list of manufacturers? 21-Nov-20 01:24 PM I am asking about the types of epoxy (are there any other options?) used to seal up the crystals by the different manufacturers 21-Nov-20 01:24 PM oh I see 21-Nov-20 01:24 PM I have no info other than "epoxy" about that, sorry 21-Nov-20 01:25 PM These are technically not mine (yet), if my repairs are successful, I get a "permanent loan" on them, and can't sell them as long as my employer is still in buisness 21-Nov-20 01:25 PM On this detector, there are epoxy and RTV silicone sealing the detector assembly in 21-Nov-20 01:26 PM My chemical supply companies that I had worked out deals with pre-pandemic for my planned LaBr3(Ce) production attempt have all up and disappeared in the few months since I got quotes so there is really no rush to find out what the crystals could be sealed with but this whole subject reminded me 21-Nov-20 01:27 PM So it's not really one material all the time, the optical window seal probably will be fairly common among different manufacturers, but it depends on the crystal material and size 21-Nov-20 01:28 PM if you end up pulling sicntillators I'm very interested in some SrI2:Eu 21-Nov-20 01:29 PM How do chemical supply places seem to have such incredible turnover? What a crazy industry... Now I am having trouble even getting quotes from places 21-Nov-20 02:40 PM In my attempt to cool down the HPGe again today, I'm fairly convinced that I've used up enough that the cold finger is no longer fully immersed in LN2 21-Nov-20 02:40 PM I'm not going to risk killing the front end especially when I'm fairly certain the vacuum is not good, but I will for sure get the Canberra ICB amplifier going before getting more LN2 21-Nov-20 02:40 PM And pumping both detectors down 21-Nov-20 03:37 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201121_173655-41BCA.jpg 21-Nov-20 03:37 PM Looks like the repair has been a success! Going to take some spectra of check sources now 21-Nov-20 04:37 PM @GigaSquirrel You know how the Red Pitaya's MCA sets really long dead times by default? You can actually decrease it and achieve fine control with left and right arrow keys! 21-Nov-20 04:37 PM Looks like decent resolution 21-Nov-20 04:37 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2C11C.png 21-Nov-20 04:37 PM How can I tell the MCA that the channel is being used in HV mode? I can adjust this when looking at the signal through the oscilloscope, but not possible in the MCA, so the MCA always operates as if it's in LV mode without any front end attenuation 21-Nov-20 08:05 PM The sample time really affects the spectrum by a great deal, not only in terms of resolution, but also relative positions of the peaks 21-Nov-20 08:05 PM The software may not be expecting a Gaussian or even semi-Gaussian pulse, so that might explain the latter part... 21-Nov-20 08:05 PM But yeah, it's pretty hard to get consistent results even with good looking peaks from its own oscilloscope application 21-Nov-20 10:43 PM Ohh awesome! 21-Nov-20 10:43 PM I just achieved 4e4 cps while accumulating a decent spectrum 21-Nov-20 10:43 PM looks like a decent NaI, please tell me this isn't the HPGe 21-Nov-20 10:43 PM Yeah absolutely, not playing with HPGe today due to lack of LN2 21-Nov-20 10:43 PM And I think it can definitely be better 21-Nov-20 10:44 PM It has Jumpers right next to the Input connector 21-Nov-20 10:45 PM Yeah but the software needs to know about it 21-Nov-20 10:45 PM does it? 21-Nov-20 10:46 PM If I use HV attenuation so I don't fry the ADC by exceeding the input voltage while the MCA software thinks it's still seeing signal with no attenuation, then for sure the pulses will be considered small 21-Nov-20 10:47 PM Not sure what you mean... The Software just sorts the signals by size, does not care about their absolute Amplitude 21-Nov-20 10:47 PM even energy calibration is just proportional / relative 21-Nov-20 10:48 PM But what is the pulse amplitude corresponding to the highest channel? Is it not equivalent to the largest pulse detectable by the ADC? 21-Nov-20 10:48 PM it is, yes 21-Nov-20 10:50 PM Well the input jumpers is just like switching your probe attenuation on regular oscilloscopes, it attenuates the signal to protect the ADCs. That mean in HV mode, I can't really take advantage of the full scale of the ADC since I can't generate a 18V pulse (or whatever the max is) 21-Nov-20 10:50 PM The maximum the amplifier can output is 10 V, but I don't want to get near it because pulse shapes distort before that around 8V, and clipping may occur too 21-Nov-20 10:50 PM But yeah ADC resolution isn't the problem really. With the number of channels I have, it's enough for NaI work 21-Nov-20 10:50 PM How the sampling average window size change the behavior after DSP is much more influential. I wish they can give a slider to adjust the window size like dead time 21-Nov-20 10:50 PM Might dig into the source code to find out if that's possible 21-Nov-20 10:57 PM ahh, now I get what you mean 21-Nov-20 10:57 PM tbh I never actually cared about those things and just dialed it in with the amp / HV to get a nice spectrum 21-Nov-20 10:57 PM and for 0-10V signals I usean attenuator 21-Nov-20 10:58 PM I only have a 30 dB SMA one 21-Nov-20 10:58 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/photo_2020-09-13_12-41-15-C6A17.png 21-Nov-20 10:58 PM So it's too much 21-Nov-20 10:58 PM But I'll make one if necessary 21-Nov-20 10:58 PM I'm more concerned about the other detector though... It does register pulses, but much lower than a detector of this size should output 21-Nov-20 11:00 PM wait the spectrum above is coming from one of the NaI cubes? 21-Nov-20 11:01 PM Yep 21-Nov-20 11:01 PM holy shit 21-Nov-20 11:01 PM It sure accumulates it quickly 21-Nov-20 11:01 PM that's extremly good for a detector that big 21-Nov-20 11:01 PM Can't count 1 uCi samples with 1 us shaping time 21-Nov-20 11:02 PM rofl 21-Nov-20 11:02 PM Too much pile up 21-Nov-20 11:02 PM you can, but only across the room 21-Nov-20 11:02 PM I want to try this, seeing a 1 uCi source through the wall 21-Nov-20 11:02 PM try loading the spectrum in interspec and read out the resolution 21-Nov-20 11:02 PM Need energy calibration first 21-Nov-20 11:02 PM well you know it's 662 keV 21-Nov-20 11:02 PM But having problem counting these 1 uCi sources... 21-Nov-20 11:02 PM Can you do one peak calibration? 21-Nov-20 11:02 PM I guess I can use the x-ray peak too 21-Nov-20 11:03 PM NaI cubes? How big is the scintillator? 21-Nov-20 11:03 PM If you have a 241Am smoke detector around that will give you the 59 keV peak for calibration 21-Nov-20 11:04 PM yep, should get you close enough 21-Nov-20 11:05 PM 135 mm diameter, 127 mm in height. Very big 21-Nov-20 11:05 PM Biggest scintillator I've seen 21-Nov-20 11:05 PM I've got many check sources, their activities are too high though and pile-up distort the spectrum 21-Nov-20 11:05 PM So I'm counting them about 20 cm away 21-Nov-20 11:08 PM it sure must be annoying, having such a big detector 21-Nov-20 11:09 PM I want to make one portable, but I can't lift it with one arm for more than 10 seconds 21-Nov-20 11:10 PM backpack! 21-Nov-20 11:10 PM I should say, hold it at arms length for more than 10 seconds 21-Nov-20 11:10 PM It might rip through my backpack 21-Nov-20 11:10 PM Both of them together, with power supplies and other electronics might be pushing 20 kg+ 21-Nov-20 11:12 PM heh, a good backpack should hold that 21-Nov-20 11:12 PM For when you have to know all your local "hot" spots 21-Nov-20 11:13 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/iu-235FA.png 21-Nov-20 11:13 PM right, throw a GPS reciever in there, too 21-Nov-20 11:13 PM I've been tempted to get a big plastic scintillator to do basically that 21-Nov-20 11:13 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/SADM28cropped29-7C323.png 21-Nov-20 11:14 PM @Addison-110m https://www.ebay.com/itm/ADIT-5-B133D01-Photomultiplier-Tube-14pin-10stage-PMT-for-Scintillator-Detector/251967744719 21-Nov-20 11:14 PM These work pretty well 21-Nov-20 11:15 PM I met someone a few years back who was on a green light team for one of those 21-Nov-20 11:15 PM oh that looks cool 21-Nov-20 11:16 PM hehe 21-Nov-20 11:16 PM that's way too cheap for what it is 21-Nov-20 11:19 PM It works well though, as you can see 21-Nov-20 11:19 PM specs read like it's great for spectroscopy 21-Nov-20 11:19 PM The same guy sells lots of bicron plastic scintillators too 21-Nov-20 11:19 PM yep, I know iRad 22-Nov-20 12:09 AM isn't that a backpack for a portable nuclear device? 22-Nov-20 12:29 AM Yep 22-Nov-20 12:44 AM If only I could track down a small amount of PPO, it'd be interesting to try and make a bismuth loaded liquid scintillator 22-Nov-20 12:44 AM you might be able to replace the ppo with p-terphenyl 22-Nov-20 12:44 AM Bi loaded for gamma sensitivity? 22-Nov-20 12:44 AM 'tho the Bi might introduce some intrinsic background 22-Nov-20 12:46 AM yeah, gamma sensitivity 22-Nov-20 12:46 AM how would you get the Bi to stay in solution? From what I gathered all the scintillation solutions are non polar 22-Nov-20 12:47 AM there are organic bismuth compounds 22-Nov-20 12:47 AM fair 22-Nov-20 12:47 AM from what? 22-Nov-20 12:48 AM Bi209/210 22-Nov-20 12:48 AM there is no stable isotope of bismuth 22-Nov-20 12:49 AM I mean, 209Bi has a half life longer than the age of the universe 22-Nov-20 12:49 AM 210Bi has a 6 day half life 22-Nov-20 12:50 AM PPO! 22-Nov-20 12:51 AM but then again there's polonium210 but even that should be avoidable if I could dig around on ebay for a bismuth compound that's a few years old 22-Nov-20 12:52 AM would lead be an option instead of Bi? 22-Nov-20 12:54 AM lead would be harder as far as inherent background 22-Nov-20 12:54 AM also more toxic 22-Nov-20 12:54 AM i'm mostly ok handling oraganobismuth compounds, heck even radioactive organobismuth compounds, the same thing with lead, yeah no 22-Nov-20 12:56 AM oh, I didn't know it was that bad 22-Nov-20 12:56 AM I mean, that's just a gut reaction 22-Nov-20 12:56 AM i haven't actually looked too far into it 22-Nov-20 01:00 AM But tell me if you get any ppo, I'd love to try this: https://inspirehep.net/files/f9484fbeef7020651a28dadab69984e7 22-Nov-20 01:10 PM oh yah @GigaSquirrel i took pictures of that PMT base, fell asleep while trying to draw out the schematic of it & forgot about it, lol 22-Nov-20 01:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201122_131017-3C970.jpg 22-Nov-20 01:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201122_130354-4BAE3.jpg 22-Nov-20 01:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201122_125935-77F72.jpg 22-Nov-20 01:11 PM good morning :D 22-Nov-20 01:12 PM i cannot find any info on anything Technical Measurement Corporation did besides make extremely space-age-lookin' neutron generators 22-Nov-20 01:13 PM how is the preamp powered? 22-Nov-20 01:15 PM honestly not sure 22-Nov-20 01:15 PM Through the two screw terminals that sticks out? 22-Nov-20 01:16 PM noh, those are just mounting posts for the whole cylindrical thing 22-Nov-20 01:16 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201122_125807-2D18F.jpg 22-Nov-20 01:16 PM e.g. 22-Nov-20 01:16 PM and it all slips into that can 22-Nov-20 01:17 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201121_153002-953C1.jpg 22-Nov-20 01:17 PM Something of similar construction, no preamp in this one, just pots to adjust bias 22-Nov-20 01:18 PM they're not screw terminals they're potis 22-Nov-20 01:18 PM right 22-Nov-20 01:18 PM The cheap ADIT 5" PMTs use the standard bicron P-14 base 22-Nov-20 01:19 PM i didn't know cheap 5" PMTs existed 22-Nov-20 01:19 PM But I prefer the preamp to be outside of the base really 22-Nov-20 01:19 PM https://www.ebay.com/itm/ADIT-5-B133D01-Photomultiplier-Tube-14pin-10stage-PMT-for-Scintillator-Detector/251967744719 22-Nov-20 01:19 PM Good up to 7.1% resolution at 662 keV apparently, with a 5" by 5"(!) NaI cylinder 22-Nov-20 01:20 PM which is so dang good for a NaI that big 22-Nov-20 01:27 PM I only achieved 11.2% tho... 22-Nov-20 01:27 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image-5172C.png 22-Nov-20 01:27 PM Many improvements to be made from here, I need to exert some pressure on the PMT (much more than expected) to ensure an even contact with the optical window, and I want to play with the sampling window size with Pevel Demin's source code 22-Nov-20 01:32 PM still, very good 22-Nov-20 01:32 PM for NaI you want ~1 µs shaping, but with one that big... your guess is as good as mine 22-Nov-20 01:35 PM I'm already using 1 us shaping, and 5 us dead time, but I get so much noise with 1 us sampling time. It appears Pevel's source code here offers much better control + you can have a pulse gen to test things too. http://pavel-demin.github.io/red-pitaya-notes/mcpha/ 22-Nov-20 01:38 PM saw that, too 22-Nov-20 01:38 PM I just much prefer the browser based thing because it runs everywhere 22-Nov-20 01:38 PM but then again I've never tried the "original" MCA 22-Nov-20 01:45 PM You'd need to delete some apps from his SD card image in order to load it onto the micro SD that came with the starter kit, it's just ever so slightly too big 22-Nov-20 01:47 PM I have a 32 GB SD in my pitaya 22-Nov-20 01:47 PM just because that's what I had on hand 23-Nov-20 09:51 AM Hm, this could be interesting 23-Nov-20 09:51 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_3835-C04B7.jpg 23-Nov-20 09:56 AM ohh neat 23-Nov-20 09:56 AM I love old catalogs 23-Nov-20 09:57 AM It’s got some specifications for a lot of stuff as well, it’s a bit long to scan but I could certainly check for things if requested 23-Nov-20 10:04 AM Finally got some info back from a Chinese chemical supplier I have bought from in the past...I guess the Chinese government hiked up the prices of rare earth compounds by a massive amount so a lot of companies are not even working with them at the moment 23-Nov-20 10:04 AM Explains why the place I had worked out a good deal with disappeared... Rare earths were their main business and they got priced out of their own market 23-Nov-20 10:04 AM My scintillator project just doubled in cost if I want to pursue it haha 23-Nov-20 10:05 AM that would explain why the couple of companies I tried to contact early this summer were all out of material 23-Nov-20 10:07 AM interesting, the prices of chinese LaBr scintillators don't seem to have changed 23-Nov-20 10:11 AM probably because they are already grown? 23-Nov-20 10:11 AM they produce on order 23-Nov-20 10:11 AM oh that is odd then 23-Nov-20 10:12 AM I guess bridgman doesn't scale well in numbers 23-Nov-20 10:14 AM The last quote I got for 1kg of LaBr3 was like $1500 + 500g of CeBr3 $850 both including shipping heh 23-Nov-20 10:14 AM Meanwhile if I want to produce the LaBr3 myself... I can get 1kg of La2O3 for $110, 500g of CeO2 for $50, and 1kg of ammonium bromide for $50 23-Nov-20 10:14 AM Then some glassware/quartz another $250 or so 23-Nov-20 10:16 AM would it be at the purity needed though? 23-Nov-20 10:16 AM 99.99% or better for everything I am looking at 23-Nov-20 10:16 AM Think that is enough... at least from what I have read 23-Nov-20 10:17 AM if you can start with hydrated forms of the salts then you could always recrystalize the hell out of it with some degree of loss 23-Nov-20 10:17 AM Easier to just go from the oxides to the tribromides from what I have been able to find 23-Nov-20 10:18 AM oh wait, right, you were starting at oxides 23-Nov-20 10:18 AM https://sci-hub.st/10.1016/0022-5088(87)90372-9 23-Nov-20 10:18 AM There is an "easy" route from La2O3 to LaBr3 via ammonium bromide 23-Nov-20 10:18 AM The CeO2 needs to be converted to Ce2O3 before that process will work but I think that can be done in a tube furnace with hydrogen gas 23-Nov-20 10:20 AM hmm 23-Nov-20 10:20 AM oh hm, this is cool https://aip.scitation.org/doi/pdf/10.1063/1.3049137 firmly meh energy resolution but it's neutron sensitive and could be grown from solution 23-Nov-20 10:23 AM how is it neutron sensitive? 23-Nov-20 10:25 AM the one I linked? I assume it's fast neutrons interacting with hydrogen 23-Nov-20 10:25 AM oh ok I was thinking thermal 23-Nov-20 10:42 AM I looked into these a little bit https://www.osti.gov/servlets/purl/1466909 23-Nov-20 10:42 AM seemed like it was definitely doable but sourcing the materials was a hassle 23-Nov-20 10:42 AM also very expensive unless you are willing to do a lot of chemistry yourself 24-Nov-20 12:00 AM https://www.youtube.com/watch?v=ibfahX4SFTA 24-Nov-20 03:16 AM Any idea on the energy range this detector might be capable of? 38mm x 38mm crystal. I’m looking to hook it up to a Gamma Spectacular. (Love the name) I can’t even find the company iRad... 24-Nov-20 03:16 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-662FC.png 24-Nov-20 03:22 AM heh, iRad is a guy on ebay making and refurbing detectors 24-Nov-20 03:22 AM 38x30 mm easily gets you in the >2 MeV range 24-Nov-20 03:22 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D458E.png 24-Nov-20 03:22 AM starting at 15-20 keV due to shielding of the case 24-Nov-20 03:22 AM do you have a pic of the whole detector, ideally the detector side? 24-Nov-20 12:38 PM Ahhh thanks Giga! I’m more interested in picking up the low energy end. 24-Nov-20 12:38 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-6874D.png 24-Nov-20 12:43 PM Can you take an end-on picture of the detector? 24-Nov-20 12:57 PM Ok, @funranium’s latest choose your own adventure has me curious.... 24-Nov-20 12:58 PM Any one here have a good recommendation for a very portable field survey meter that would be good for finding low energy x-ray leaks? 24-Nov-20 12:58 PM https://www.orau.org/ptp/collection/Miscellaneous/pacemaker.htm 24-Nov-20 12:58 PM (I to am going to tag @funranium) 24-Nov-20 12:58 PM This states the surface dose rate is 5-15 mrem/h 24-Nov-20 12:58 PM Where is that coming from? 24-Nov-20 12:58 PM Pu-238 is a 100% alpha emitter. 24-Nov-20 12:58 PM And U-234 has a 3/4 million year half life. 24-Nov-20 12:58 PM Also, what’s up with the postal service? 24-Nov-20 12:58 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-0B579.png 24-Nov-20 12:58 PM A_1 and A_2 are not activity or dose rate units I’ve ever seen. 24-Nov-20 01:07 PM https://www.law.cornell.edu/cfr/text/49/173.435 24-Nov-20 01:07 PM They are referencing a federal standard ( https://www.law.cornell.edu/cfr/text/49/173.433 ) that gives you that chart 24-Nov-20 01:18 PM X-ray? 24-Nov-20 02:15 PM How low? 24-Nov-20 02:15 PM The A1 & 2 tables are the worst Choose Your Own Adventure but they’re one that waste and shipping managers navigate everyday. 24-Nov-20 02:17 PM Also, price and X-ray intensity? 24-Nov-20 02:17 PM (I have an idea or two) 24-Nov-20 02:25 PM I love my contamat for that 24-Nov-20 04:31 PM My answers might be wrong but anyway: Natural U has unlimited A2 so that’s fine (the uranium/thorium manufactured articles clause only applies to solid metal I think) the pacemaker is an instrument/article and it’s special form, they’re usually 3Ci so will be under 2.7Ci after a decade of use or more, the Am limit is 27 uCi (A2/1000) which won’t be reached (even though the NRC license says you shouldn’t have taken them apart to begin with). The Ra ornaments have no quantitative information of their activity so not allowed at all. Ra gamma will easily be detectable if monitors are present, and if appropriate labelling and documentation and activity are not provided then it is likely to get you in trouble regardless of whether or not it is legal - and if activity isn’t known and documented then it technically isn’t legal anyway. 24-Nov-20 04:40 PM (a, n) reactions with oxygen and other light elements produce neutrons because the 238Pu is such an intense alpha source. They actually use enriched 16O to make the PuO2 for RTGs to remove most of the neutron dose, since 16O has much less cross section. https://www.lanl.gov/orgs/nmt/nmtdo/AQarchive/05spring/heart.html 24-Nov-20 04:42 PM Nice find 24-Nov-20 06:02 PM I'm looking for even smaller than the contamat, this has to fit in my field service kit which is my pelican 1535. I don't really care about the actual x ray rate as much as just a yes/no is there x rays leaking if that makes sense. The use case is looking for leaks on electron microscopes, so really its a case of there should be nothing detectable. I'm looking at the ludlum 26 and the end windows 2401 series, but if anyone has anything else that fits in that vane that they like I'm all ears. 24-Nov-20 06:02 PM *end window or pancake 24-Nov-20 06:47 PM Interesting, most of these pancake or even super long end window type GM tubes have fairly low areal densities 24-Nov-20 06:47 PM @AdamMcCombs Not exactly a survey probe, but I picked up one of these, LND4567 xenon filled proportional counter 24-Nov-20 06:47 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201124_204739-903F0.jpg 24-Nov-20 06:47 PM 0.002" beryllium window means it can see really low energy x-rays 24-Nov-20 06:47 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F4B09.png 24-Nov-20 06:47 PM https://www.lndinc.com/products/x-ray-proportional-counters/4567 24-Nov-20 06:47 PM With okay resolution and covers the range for a SEM. The areal density specified by LND is surprisingly high, 9.2 mg/cm^2 24-Nov-20 06:47 PM https://www.ebay.com/itm/LND-45432-Beryllium-Side-Window-Proportional-Counter-Nuclear-Radiation-Detector/113893803121 24-Nov-20 06:47 PM This would be the bigger version of that. It should beat anything with a mica window, with even higher efficiency for some of the higher energy x-rays 24-Nov-20 06:47 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E2756.png 24-Nov-20 07:08 PM Oh cool 24-Nov-20 07:08 PM That thing is pretty small 24-Nov-20 07:08 PM Although I like the idea of a mica window a lot better than a beryllium one... 24-Nov-20 07:10 PM Just keep it covered, it's okay 24-Nov-20 07:18 PM Its going in my flight case with the rest of my tools, which TSA really likes to dig through. They broke the screen on my oscilloscope when the threw it in the case with out the cover for the screen next to the bag of tool they opened... 24-Nov-20 07:19 PM Okay, yeah they broke my He-3 tube too... 24-Nov-20 07:20 PM Im tempted to put this in my laptop bag to protect the window TBH 24-Nov-20 07:20 PM And hey always having a GM handy is nice 24-Nov-20 07:21 PM You'd need quite a lot of voltage to get this up to GM mode, and it won't be at all stable 24-Nov-20 07:24 PM Yeah I'm just going to stick with something small and integrated 24-Nov-20 07:24 PM This really just needs to be something I can just pull out and use 24-Nov-20 07:40 PM I used a 2401 a bit a couple years ago, seemed like a pretty nice meter. 24-Nov-20 07:40 PM Though I was being told to calibrate it, a pancake gm tube, for dose rate 24-Nov-20 07:45 PM Did they have a compensator for it at least? 24-Nov-20 07:46 PM Can you energy compensate a pancake GM? 24-Nov-20 07:46 PM I guess not in the detector contruction itself, but through filters 24-Nov-20 07:48 PM You can put a filter to help flatten out the low energy range 24-Nov-20 07:48 PM Yeah here we go 24-Nov-20 07:48 PM https://ludlums.com/products/all-products/product/dose-filter 24-Nov-20 07:48 PM Looks like its not for the 2401 though 24-Nov-20 07:48 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/EnergyGraph-8F1DA.png 24-Nov-20 07:48 PM https://ludlums.com/products/all-products/product/model-2401-p-dose 24-Nov-20 07:48 PM So they sell a 2401 with a dose filter you can slide in front of the window, that is kinda cool. 24-Nov-20 07:55 PM No 24-Nov-20 07:55 PM That’s fire departments for you 24-Nov-20 07:55 PM I think you can make one, out of a thin tin sheet? 24-Nov-20 07:55 PM But it'll be tricky to calibrate 24-Nov-20 08:16 PM As a general rule, if you can help it, you don't take your beryllium window detectors into the field, you bring samples to them. Especially when TSA may rummage. 24-Nov-20 08:17 PM Uh oh everyone 24-Nov-20 08:17 PM Beryllium twitter is here lol 24-Nov-20 08:17 PM I never left. 24-Nov-20 08:17 PM As someone who spent four [MANY EXPLETIVES DELETED] months doing decon on a lab where the windows of several detectors that had gone into the field, got slightly moist, and then started shedding oxide... yes, I am Beryllium Twitter. 24-Nov-20 08:22 PM Yeah everyone thinks the risk is only from cutting, but its supper not 24-Nov-20 08:23 PM Hmm well looks like I might need to do a beryllium window swap... 24-Nov-20 08:23 PM Will be tricky to get the old one off 24-Nov-20 08:27 PM Maybe stick with mica in the context that it has to be field portable, even though you lose some low end energy inevitably 24-Nov-20 08:28 PM [sagenods] Yep. A thin mica sheet cover will save a lot of pain of trying to swap. 24-Nov-20 08:29 PM Hmm, not really much of an option for a low energy HPGe... 24-Nov-20 08:29 PM I definitely don't need it to be portable 24-Nov-20 08:29 PM Covering the original with another beryllium foil is an option, but I'd rather not do that 24-Nov-20 08:38 PM Hmm. Well, happy to give Be work advice if you need it. Tl;DR version: get respirator fit tested, wear a full face with HEPA cans (PAPR preferably) if you can lay hands on them, frequent glove stripping, and plenty of wet wipedown to catch any shed. 24-Nov-20 08:39 PM Need to open the detector up first and see how the window is attached on the other side. Probably a lot of epoxy 24-Nov-20 08:39 PM If it is too tricky, I'll mount the new window on a new stainless shell, and mount that onto the original flange 24-Nov-20 08:40 PM Wet wipes like a mofo. 24-Nov-20 08:41 PM I am extra motivated to fix the second detector since I learnt my employer is now looking for a low energy HPGe 24-Nov-20 08:41 PM They will find an employee very eager to sell them one 24-Nov-20 08:41 PM I just don’t want to ever mess with labile BeO if I don’t really really have to 24-Nov-20 08:41 PM Can you even chemically test for it, at the dangerous concentrations? 24-Nov-20 08:42 PM Yes, but it's slow and expensive. 24-Nov-20 08:44 PM Radioactivity is much easier, you can track where it is. 24-Nov-20 08:44 PM Be worker skills are valuable, especially if you have an interest in future work in Weird Radiation Stuff. Eventually, it's gonna crop up. Like anything of the other dangerous things we discovered are great, it's something you treat with respect and work with cautiously to protect yourself, others, and the workspace. 24-Nov-20 08:44 PM And yes, that is what makes health physics the best field. At least I get a dang detector for the thing I'm working with. I pity the industrial hygienists. 24-Nov-20 08:57 PM Speaking of shedding 24-Nov-20 08:57 PM Do RF power transistors, RF attenuators and RF resistors with BeO shed when exposed to moisture? 24-Nov-20 08:57 PM remembers all of those RF things he pulled from damp sheds and from scrap yeards, where it had been in the rain. 24-Nov-20 09:02 PM They can. Be alloy stuff will oxidize BeO out of the alloy but it's much slower. Still a problem, but slower. 24-Nov-20 09:04 PM They use BeO as insulators 24-Nov-20 09:04 PM usually a small sliver between the RF power transistor and the tab/the part that's bolted to the heatsink 24-Nov-20 09:04 PM ^this is always my fear with old EDS detectors 24-Nov-20 09:04 PM Oh, the ceramic? 24-Nov-20 09:04 PM Yes 24-Nov-20 09:04 PM I have understood the ceramic is safe to handle as long as you don't mechanically damage it. 24-Nov-20 09:05 PM Don't crumble and snort it and you're fine. 24-Nov-20 09:05 PM oki 24-Nov-20 09:05 PM Or, as they used to do in the Spectra Physics breakdown room, SMASH THE INSULATOR SHEATHS WITH A SLEDGEHAMMER. 24-Nov-20 09:05 PM And there’s the nuclear adjacent field.... 24-Nov-20 09:05 PM Gyroscopes 24-Nov-20 09:05 PM Don't do that either. 24-Nov-20 09:07 PM As in, a very useful use of Be to deliver the radioactive stuff to the bad guys to within tens of meters CEP very quickly. 24-Nov-20 09:15 PM has once managed to decap a MRF150 RF power transistor by applying too much mechanical force when unscrewing it 24-Nov-20 09:15 PM That's fine 24-Nov-20 09:15 PM I have done that deliberately to some 900MHz and 1800MHz LDMOS to see how the internal matching is done. 24-Nov-20 09:15 PM The BeO is between the die and the case. 24-Nov-20 09:16 PM that sounds expensive 24-Nov-20 09:33 PM Nah, it was all telco scrap 25-Nov-20 01:13 AM huh 25-Nov-20 01:13 AM what the actual 25-Nov-20 01:13 AM those weird PMT bases actually power the preamp from the HV 25-Nov-20 01:13 AM @rdpierce was right 25-Nov-20 01:13 AM I still stand my point that that's stupid 25-Nov-20 01:13 AM but 25-Nov-20 01:13 AM ??? 25-Nov-20 01:13 AM also has like random shorted resistors inside and whatnot 25-Nov-20 01:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4045E.png 25-Nov-20 01:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F1D54.png 25-Nov-20 01:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-8A483.png 25-Nov-20 01:13 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6D606.png 25-Nov-20 01:13 AM it's so weird 25-Nov-20 05:01 AM Power semiconductors with a BeO substrate will usually have the BeO sealed inside a package where it’s not exposed, anyway. 25-Nov-20 05:02 AM but then what's the point of the BeO? 25-Nov-20 05:02 AM I thought it's there to conduct the heat outside 25-Nov-20 05:23 AM great use for 16k channel mcas 25-Nov-20 05:23 AM getting great spectra from signals way to small 25-Nov-20 05:23 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-1AB88.png 25-Nov-20 05:23 AM I'm not even using the first 1k channels 25-Nov-20 05:36 AM The BeO is there to conduct the heat from the silicon die to the thermal interface, usually a slab of copper which is then bolted to the heatsink, or soldered to a copper heatspreader 25-Nov-20 05:53 AM ah, fair 25-Nov-20 06:53 AM If you reverse engineer the schematic, @GigaSquirrel, I’d be interested. I’m also interested in seeing how much current it pulls off of the HV supply. 25-Nov-20 06:54 AM I'll do that at some point 25-Nov-20 06:54 AM can't measure current in my current setup (pun not intended), but the original hvps can supply 1 mA max 25-Nov-20 06:54 AM https://web.archive.org/web/20010608044245/http://www.milelectronics.com/p1serV.html the VH20 25-Nov-20 07:03 AM The BeO is an electrical insulator with high thermal conductivity, and it keeps the active electrical parts, which may be at high voltage, isolated from the case/package. 25-Nov-20 03:26 PM Why is aluminum nitride not more commonly used as heat conducting rf insulators? 25-Nov-20 03:26 PM It has excellent rf and microwave properties and super high heat conductivity 25-Nov-20 03:58 PM These days it is 25-Nov-20 03:58 PM It's replacing BeO in that service 25-Nov-20 03:58 PM If you look up datasheets for current production ldmos transistors there are no BeO warnings anymore 25-Nov-20 03:58 PM Unlike for early 00's and stuff prior to that 25-Nov-20 03:59 PM Ah yeah I'm seeing lots of applications for high power microwave windows, but good to see that advanced ceramics are being used on a large scale as well 25-Nov-20 06:35 PM Anyone by chance know who eBay maximusenergy is? They sent me a question about some SEM parts and have a bunch of radiation detectors for sale 25-Nov-20 06:36 PM Yeah 25-Nov-20 06:36 PM He is something else completely 25-Nov-20 06:36 PM Call? 25-Nov-20 06:36 PM Something else? 25-Nov-20 06:43 PM Oh, I think I bought my way-overpriced 3He tube and a jank old Tennelec HV PSU from him 25-Nov-20 06:43 PM back in .. 2018? wow 25-Nov-20 06:43 PM (in their defense, they have much cheaper ones for sale now, and a second near-equivalent HVPSU I found at a local flea market later on is also busted) 26-Nov-20 03:57 PM https://hackaday.com/2020/11/19/the-shipping-industrys-transition-to-atomic-power-and-faster-deliveries/ 26-Nov-20 04:56 PM As the first step is to get underwriters to sign off on them, that's unlikely without significant government support. The next difficulty is that the shortcuts that shipping industry loves, Panama, Gibraltar & Suez, are closed to them which means everything has to go around the Horn. This takes us back to underwriters being unimpressed. 26-Nov-20 05:25 PM Also the whole thing where pirates are kinda a thing still 26-Nov-20 05:35 PM But it is fine clickbait. 26-Nov-20 09:44 PM Eh, china to California would be good enough for me 26-Nov-20 09:44 PM No shortcuts that route 26-Nov-20 09:44 PM Govt already uses them, so that seems reasonable 26-Nov-20 11:46 PM http://www.shalomeo.com/category/scintillation-crystal-materials-63.html Found this seller 26-Nov-20 11:46 PM sadly no prices but I'll ask for a few quotes 27-Nov-20 12:44 AM heh, a friend of mine sent me a spectrum of some sand from the jupiter factory 27-Nov-20 12:44 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-C8443.png 27-Nov-20 12:44 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-27935.png 27-Nov-20 12:44 AM ceeeeesium 27-Nov-20 12:44 AM also Eu154, Am241 and some Co60 27-Nov-20 12:44 AM nice and colorful spectrum 27-Nov-20 03:43 AM ok, so 27-Nov-20 03:43 AM uhm 27-Nov-20 03:43 AM tc155a pmt base 27-Nov-20 03:43 AM maestro claims <6.2% fwhm 27-Nov-20 03:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201127_123706-F3C52.jpg 27-Nov-20 03:43 AM but I don't trust it 27-Nov-20 03:43 AM will take spectrum for a bit longer and then ask interspec 27-Nov-20 01:03 PM apparently it came from here: https://www.youtube.com/watch?v=CdhdCbDch6A 27-Nov-20 01:13 PM Sigh. Take nothing but photographs, leave nothing but footprints, etc. 27-Nov-20 01:18 PM well yes 27-Nov-20 01:18 PM from what I gathered that was the dust they had on them, eg. in the filters 27-Nov-20 01:18 PM looks like she's taking the bottles to read the lables and then puts them back 27-Nov-20 06:15 PM I have identified the sand. 27-Nov-20 06:15 PM I did SEM + EDX on it. 27-Nov-20 06:15 PM Then did some research in journals and realized what it was likely being used for. 27-Nov-20 06:15 PM And did pXRF to confirm. 27-Nov-20 06:15 PM It’s primarily Si, O, and Fe. 27-Nov-20 06:15 PM I might have seen a small Mg peak. 27-Nov-20 06:15 PM The eureka moment was when I checked academic literature and realized iron oxide coated sand and Mg coated sand is used as an adsorbent. 27-Nov-20 06:15 PM Two possibilities: 27-Nov-20 06:15 PM 1. The Jupiter factory lab was used to test decontamination / remediation. 27-Nov-20 06:31 PM So I am imagining that they may have tried to, say, hose down a contaminated truck, collected the contaminated water, pumped it through iron oxide coated sand, and the Cs, Eu, Am, etc. absorbs on the sand. 27-Nov-20 06:31 PM Then they can flush acid through the sand and elute the fission products out. So you can clean a large amount of contaminated water, clean it, get clean water back, and a smaller quantity of much more contaminated acid. 27-Nov-20 06:31 PM 2. We know there were alpha disks plated with Pu. We also know there were soil bags down there. 27-Nov-20 06:31 PM I can easily see them wanting to quantify Pu activity per sq meter or kg of topsoil at many thousands of grid points or more. 27-Nov-20 06:31 PM To process samples for alpha counting, you typically ash them, digest them in acid, put the acid through an ion exchange resin, and do elutions to do chemical separations. The you electrodeposit onto a metal planchette and count in an alpha spectrometer. 27-Nov-20 06:31 PM Ion exchange resin is expensive. 27-Nov-20 06:31 PM I wonder if iron oxide coated sand was used as an adsorbent as a sort of poor man’s ion exchange resin, which you’d use if you needed to digest and separate thousands of samples into alpha plates. 27-Nov-20 06:31 PM This makes a lot of sense. The boxes of black sand are really spicy. 27-Nov-20 06:31 PM They were locked in a fenced off caged area. Probably because they were hot. 27-Nov-20 06:31 PM Bionerd originally thought the sand was shielding something hot and was digging though it. 27-Nov-20 06:31 PM She was wrong. 27-Nov-20 06:31 PM But she noticed that she made the air radioactive when throwing sand up in the air. 27-Nov-20 06:31 PM What’s also interesting is that everyone who takes samples of the sand finds it is hot. 27-Nov-20 06:31 PM This isn’t something you’d expect if it were normal sand, and there were hot particles in it. 27-Nov-20 06:31 PM The sand is UNIFORMLY slightly hot. 27-Nov-20 06:31 PM Which makes sense contaminated water was pumped through the sand to adsorb the radionuclides. 27-Nov-20 06:31 PM And which explains why big boxes of sand are really hot. There’s nothing hot in the boxes being shielded. But if each particle of sand is equally lightly contaminated, a large box of it will be really spicy. 27-Nov-20 07:54 PM That makes sense. 27-Nov-20 08:44 PM Unfortunately the EDX spectra are stuck on a PC currently in my living room running Windows 3.11 and getting them off there is going to be fun.... 27-Nov-20 08:44 PM Let’s see, which is less painful.... I have to boot the thing with keyboard and mouse using PS/2 connectors either way, run EDX, and screen cap spectra into Windows Paint. 27-Nov-20 08:44 PM From there, do I pull out my hair getting TCP/IP to work on my home network and setting up an FTP server to upload them? 27-Nov-20 08:44 PM Or do I pull the hard drive, use a friend’s USB to IDE, and copy the files that way? 27-Nov-20 09:01 PM Or just get yourself an USB floppy drive 27-Nov-20 09:37 PM so my dad gave me a challenge 27-Nov-20 09:37 PM import 10g of raw uranium containing material 27-Nov-20 09:37 PM I wonder what the export conditions for minerals and rocks containing uranium 27-Nov-20 09:40 PM @SleepyOwl Joyce There are many Chinese Autunite sellers 27-Nov-20 09:40 PM And as far as I know, Singapore shouldn't have any import regulations on them 27-Nov-20 09:40 PM https://www.ebay.com.sg/itm/Wholesale-price-10-g-10-P-Natural-Autunite-Crystal-Cluster-Rare-Mineral-Specimen/124364865936 27-Nov-20 09:42 PM I see 27-Nov-20 09:43 PM Was tempted to bring some samples that I suspected to contain thorium or uranium compounds when I was home a few weeks ago 27-Nov-20 09:43 PM But didn't get them since it's really just as easy to acquire (in small quantities) in the US 27-Nov-20 09:43 PM Home as in? 27-Nov-20 09:44 PM Hong Kong 27-Nov-20 09:44 PM Ah 27-Nov-20 09:45 PM If you know anyone who likes fluorescent minerals you could get rid of a nice Autunite specimen pretty easily if you didn't want it after buying it on ebay heh 27-Nov-20 09:45 PM The glow is very impressively intense 27-Nov-20 09:45 PM I see 27-Nov-20 09:45 PM this also came across my radar 27-Nov-20 09:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/wm_b_johnson_gsm_110_geiger_co_1599452128_-6B7D8.png 27-Nov-20 09:45 PM It's in an unknown state as usual 27-Nov-20 09:49 PM Taped on cover could be a plus if it is used as it was intended...or minus if it is hiding a broken window 27-Nov-20 09:49 PM Do not recognize that specific detector model to give you any info beyond that unfortunately but someone else here might know about them. Funny how similar but different a lot of meters in that style are 27-Nov-20 09:56 PM I've got a similar meter 27-Nov-20 09:56 PM I'll dig around for a manual but that one might be newer than mine if that says 110 27-Nov-20 09:57 PM it is a WM B Johnson GSM -110 Geiger Counter 27-Nov-20 09:58 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/GSM-110_OPERATION_MAINTANCE_MANUAL-797E8.pdf 27-Nov-20 09:58 PM not exactly the worlds most complex meter as far as I can tell 27-Nov-20 09:58 PM I bought a gsm-10s a few years ago with a few issues and got it back up and running 27-Nov-20 10:03 PM They're effectively knock-off a Ludlum Model 3 with 44-9 probe. Fairly easy to calibrate and durable. If it's a decently cheap price, a decent buy. 27-Nov-20 10:03 PM The pancake GM is the expensive part to replace and even that's not bad. 27-Nov-20 10:03 PM $80 SGD is the asking price 27-Nov-20 10:03 PM Oh jeez. Swoop on that. 27-Nov-20 10:03 PM Even if it's completely busted, that's a good price just for messing around with it fun. 27-Nov-20 10:04 PM ^ 27-Nov-20 10:04 PM I bought a half broken one for a bit more than that once 27-Nov-20 10:05 PM If the probe is in good shape, you will have instantly made a profit. 27-Nov-20 10:06 PM let me go down then next week 27-Nov-20 10:06 PM @iz wanna come along and snag a geiger counter? 27-Nov-20 10:06 PM they're saying that it's $80 each 27-Nov-20 10:06 PM Im a big fan of my ludlum 12, very easy to repair 27-Nov-20 10:06 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/WIN_20140908_175603-878E0.jpg 27-Nov-20 10:06 PM so they're probably carrying more than 1 27-Nov-20 10:07 PM EACH?!?! 27-Nov-20 10:07 PM yes. 27-Nov-20 10:07 PM Each. 27-Nov-20 10:08 PM The probes alone are worth that if the windows look good 27-Nov-20 10:08 PM Bring a shopping cart. 27-Nov-20 10:10 PM Nice paint job 27-Nov-20 10:10 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-2DCFB.png 27-Nov-20 10:10 PM $80 SGD == $60 USD 27-Nov-20 10:10 PM They sell very thin painter's tape that's great for that kind of work 27-Nov-20 10:12 PM I might have to do something like that, especially if I get that old eberline pic-6 working again 27-Nov-20 10:12 PM can't figure out what the heck is wrong with that darn meter 27-Nov-20 10:13 PM as I thought - there's only one place in Singapore that would have stuff like this 27-Nov-20 10:13 PM and these are just multiple seller accounts that are listing for the same business 27-Nov-20 10:13 PM The ludlum 12 is especially cool because it has an adjustable pulse height discriminator 27-Nov-20 10:13 PM And adjustable HV setpoint and trim pots for every x# scale 27-Nov-20 10:13 PM Very tunable 27-Nov-20 10:15 PM I still need to finish fixing mine up 27-Nov-20 10:15 PM Still can't believe the seller did not list one of them up separately just for the SNM sticker it has 27-Nov-20 10:15 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20200221_185108104_-_Copy-F5724.jpg 27-Nov-20 10:19 PM SNM? 27-Nov-20 10:19 PM special nuclear material 27-Nov-20 10:19 PM oh 27-Nov-20 10:19 PM oh nice 27-Nov-20 10:20 PM I wonder how these probes work 27-Nov-20 10:20 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-B3A5C.png 27-Nov-20 10:20 PM how do you tell the difference between the alpha, beta and gamma radiation? 27-Nov-20 10:21 PM Filters 27-Nov-20 10:22 PM The tube in that probe is probably a rough equivalent to this: https://www.lndinc.com/products/geiger-mueller-tubes/7311/ 27-Nov-20 10:22 PM Also not sensitive to gamma directly, they are looking at photoelectron emission 27-Nov-20 10:23 PM For the probe in the listing photo you shared 27-Nov-20 10:23 PM I see 27-Nov-20 10:25 PM Those are what are in this probe that is basically the Ludlum branded equivalent of the probe in the listing photo: https://ludlums.com/products/all-products/product/model-44-9 27-Nov-20 10:25 PM I see 27-Nov-20 10:27 PM This is the probe i use now 27-Nov-20 10:27 PM https://www.thermofisher.com/order/catalog/product/HP210AL 27-Nov-20 10:27 PM Pretty much equivalent 27-Nov-20 10:27 PM Yup think those use the same LND tube too 27-Nov-20 10:30 PM Anyone willing to help me think through a broken meter? It's a meter I got and have been trying to understand for a few years now 28-Nov-20 12:54 AM PMT divider PCBs! 28-Nov-20 12:54 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-7EAA9.png 28-Nov-20 12:54 AM fits well on B14A sockets, hit me up if you want some 28-Nov-20 12:54 AM is a divider for positive high voltage and decouples the anode signal 28-Nov-20 06:35 AM Pretty, @GigaSquirrel ! 28-Nov-20 06:35 AM One of my long abandoned projects is to build a proper NIM compatible base + preamp for a proprietary immunoassay lead well. 28-Nov-20 06:35 AM @rfs I think the floppy drive is bad. 28-Nov-20 06:40 AM what makes a base nim (in)compatible? 28-Nov-20 06:40 AM also thanks ^.^ 28-Nov-20 06:42 AM It uses a completely proprietary preamp power + signal connector. XLR! 28-Nov-20 06:42 AM ohh I see 28-Nov-20 06:42 AM I also haven’t figured out what voltage the proprietary preamp feeds it. 28-Nov-20 06:42 AM But it’s a beautiful Bicron well scint. 28-Nov-20 06:42 AM Inside a heavy lead castle. 28-Nov-20 06:43 AM oh neat 28-Nov-20 06:43 AM Got it at a medical auction for like $20 with a whole lot of hernia repair surgical kits. 28-Nov-20 06:43 AM Nobody knew what it was. 28-Nov-20 06:43 AM Also got a broken PMT and bad NaI well scint that I used for a terdown video. I don’t think the video editing ever got finished on it. 28-Nov-20 06:43 AM The thing uses a weird proprietary SCA. 28-Nov-20 06:43 AM Very clearly a medical device for radioimmunoassay. 28-Nov-20 06:47 AM oh I think I remember the scinti in lead, you posted a pic of it on twitter and linked that here recently 28-Nov-20 06:47 AM Yeah 28-Nov-20 06:48 AM I'm having great results with the well here, with the new base it looks like 6.5% FWHM 28-Nov-20 06:48 AM had to close the window and turn on heating to stabilize the room temperature >.< 28-Nov-20 07:56 AM yep, interspec agrees with maestro 28-Nov-20 07:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A3695.png 28-Nov-20 12:10 PM Anyone ever used an eberline pic-6 before? Is it supposed to slightly whine from the HV section when in use? 28-Nov-20 12:10 PM yes I know it's ancient and fairly useless but it was my second (third but the first real one) ever radiation meter so I want to try and fix it 28-Nov-20 12:29 PM I have zero knowledge of that detector specifically but it is my experience that with older meters the HV stuff often does that but not so loud that you can hear it with the case closed up 28-Nov-20 02:35 PM Slight whine from HV converters is not unusual, especially in older gear. 28-Nov-20 02:37 PM ok, that's what I figured, and the HV still works so that's probably not the issue. I feel like I'm running out of things to test on this meter and really hoping the issue isn't the tube has gone bad. 28-Nov-20 02:42 PM I don't have experience with that specific meter, but I know that many older meters whine 28-Nov-20 02:54 PM HV works, and HV is getting to the tube? If there’s a big resistance in series with the HV to the detector then you need to factor in your meter impedance when measuring it or you will get a false, divided voltage reading. 28-Nov-20 02:54 PM So let’s assume the detector itself is good and HV is good. Look for pulses after the coupling capacitor? 28-Nov-20 03:14 PM It's an ion chamber, not a gm tube, that's the tricky part. I've been measuring things with a 10 GOhm voltage divider attached to my meter 28-Nov-20 03:14 PM I should double check the hv connection to the tube 28-Nov-20 03:26 PM @Addison-110m Maybe check if your input JFET is still alive? They are so sensitive that even very small ESDs can destroy them. You should be able to measure some voltage on the source of the JFET if it's still good 28-Nov-20 03:26 PM In your meter, this should be Q5 28-Nov-20 03:26 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A631D.png 28-Nov-20 03:27 PM yeah, I'll try that, I tried replacing that one before but given they way the new part was shipped I have some doubts about whether it would have been alive when it was installed 28-Nov-20 03:27 PM thanks 28-Nov-20 03:28 PM Did you get it from Mouser? I have yet to receive a dead-on-arrival IC from any of the major distributors yet 28-Nov-20 03:29 PM no, I didn't, it was just from some random ebay seller 28-Nov-20 03:29 PM think I couldn't track one down from a proper manufacturer at the time 28-Nov-20 03:31 PM https://www.mouser.com/ProductDetail/InterFET/2N4118A?qs=OxRSArmBDfwN1BCcM7lPmA%3D%3D 28-Nov-20 03:31 PM Pretty pricey for an electrometer JFET 28-Nov-20 03:31 PM yeahhh 28-Nov-20 03:31 PM at that price it's almost worth just buying another identical meter for parts given how cheap they are 28-Nov-20 03:31 PM but I think I'll take another look at the source of that transistor 28-Nov-20 03:41 PM And check the voltages on the second input of the differential amplifier 28-Nov-20 03:41 PM So that's the 2.6 V and 2.9 V flags on the schematic 28-Nov-20 03:41 PM It's possible that somehow the voltage reference failed and so the differential amplifier is not working properly 28-Nov-20 03:44 PM I think the voltage reference is still good, I remember checking that 28-Nov-20 03:44 PM but I'm skeptical about the input JFET again thinking back to how it was replaced 29-Nov-20 09:20 PM Looks like I'm getting an x-ray tube 29-Nov-20 09:20 PM And it was a good idea to save up for lots of lead 29-Nov-20 09:20 PM I might be spending close to $300 just in lead here... For thicker sheets, this is the best place I've found online, just over $2 per lb with shipping https://www.bestmaterials.com/detail.aspx?ID=9331 29-Nov-20 09:37 PM Shipping leadtime has two meanings 29-Nov-20 10:25 PM That’s a pretty good price, might look at that for eventual detector shielding as a middle layer between scrap lead and low Z stuff 29-Nov-20 10:27 PM I'm not buying yet, since there is someone selling thousands of pounds of soft lead reasonably close by 29-Nov-20 10:27 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/00I0I_fayHqA9FLcb_0c80gg_1200x900-C1DC0.png 29-Nov-20 10:27 PM Oh nice 29-Nov-20 10:28 PM $1 per lb on scrap soft lead and 50 cents per pound on a mixture of lead alloy, other scrap metal and soft lead 29-Nov-20 10:28 PM He will entertain trades for livestock apparently 29-Nov-20 10:28 PM Interesting 29-Nov-20 10:29 PM Gonna hit up the RSO at work 29-Nov-20 10:29 PM They pay insane prices for lead in bulk, like $3.5 per lb or something 29-Nov-20 10:29 PM Plus shipping 29-Nov-20 10:29 PM https://rockford.craigslist.org/mat/d/harvard-scrap-metal-soft-lead-1per/7233134328.html 29-Nov-20 10:29 PM @rdpierce This might be close enough to you too, in case you are looking for cheap lead 29-Nov-20 10:31 PM Actually, found someone in portland asking 1.25 a pound (browsing for myself) 29-Nov-20 10:31 PM but no detector to build shield for right now so why am I even looking 30-Nov-20 12:42 AM ohhh that's a very good price 30-Nov-20 07:36 AM Thanks for the lead on the lead. 30-Nov-20 07:57 AM from all I gathered p-terphenyle dissolved in epoxy resin should give a working (albeit terrible) scintillator 30-Nov-20 07:57 AM I just ordered some and will try some experiments 30-Nov-20 07:57 AM ideally I'd have some shifter in there, but I can't get those easily 30-Nov-20 09:38 AM Oh very fun 30-Nov-20 10:36 AM I'm seeing a weird effect where if I expose a NaI scintillator in an aluminum housing to a 241Am source the count rate increases but not immediately and then when the source is removed it there's a few seconds of delay before it decreases. Anyone have any ideas? 30-Nov-20 10:36 AM None of the reactions I’ve seen from alpha particles on aluminum seem to fit, all the products have multi minute half lives 30-Nov-20 10:42 AM wait what 30-Nov-20 10:42 AM the count rate drops slower than you remove the source? 30-Nov-20 10:43 AM yes 30-Nov-20 10:43 AM Maybe it’s just the meter being weird 30-Nov-20 10:43 AM yeah I'd guess so 30-Nov-20 10:43 AM slow time constant? 30-Nov-20 11:11 AM Don't have precise enough data for one yet 30-Nov-20 11:11 AM I'll be trying it with a larger scintillator and hopefully a larger source 30-Nov-20 11:14 AM dead-ish NaIs can have a strong afterglow, but then they usually also have way lower light output 30-Nov-20 11:14 AM but that would not explain the slow rise 30-Nov-20 11:14 AM which can only be explained with something in the electronics, not the detector imo 30-Nov-20 11:17 AM I'll try it with a different type of source, see if there's still some sort of afterglow 30-Nov-20 11:17 AM Given the detector has always been an ill fit for the meter, that makes sense. 30-Nov-20 11:17 AM Hm, might have to get back to figuring out how to open this probe up in a way that won't destroy the scintillator if the detector housing is what keeps it from the air 30-Nov-20 11:23 AM but the afterglow should not give counts, just... light 30-Nov-20 11:23 AM it really just sounds like a slow time constant in your meter 30-Nov-20 11:25 AM The count rate appears to not change by ear which is the weird thing but that's the opposite of reliable 30-Nov-20 11:28 AM huh? 30-Nov-20 11:28 AM so the meter changes but it doesn't sound like more counts? 30-Nov-20 11:59 AM I meant the decrease 30-Nov-20 11:59 AM doesn't sound like the count rate drops off 30-Nov-20 11:59 AM I'll take some proper measurements this afternoon 30-Nov-20 04:24 PM An RC circuit is typically used as a filter. 30-Nov-20 04:24 PM The needle on analog meters typically has a significant lag in both directions. 30-Nov-20 04:24 PM I would expect clicks to show up and disappear immediately, but the needle lagging slowly to rise and fall. 30-Nov-20 04:24 PM Heh. Now I can actually understand the math. You’ve got a decaying exponential system function, and you’re convoluting it in the time domain with the count pulses. 30-Nov-20 07:04 PM Seriously, everyone should check out this majesty. https://twitter.com/RSudowe/status/1333568041637048322 30-Nov-20 07:06 PM So the Rutherfordium is made in a LINAC? 30-Nov-20 07:07 PM Not a LINAC in this case but, yes, an accelerator. 30-Nov-20 07:09 PM We used to have a system of pneumatic tubes that transport materials to be irradiated under the LINAC, that would be too slow in this case though since manual operation was required 30-Nov-20 07:12 PM And a special beam line at that, with a Californium target and C-12 beam as I recall. 30-Nov-20 07:14 PM Does this accelerator still exist? Looks like Colorado State has a L-band electron LINAC and a FEL now, but no mention of a cyclotron or something like that 30-Nov-20 07:19 PM This work wasn't done at CSU. I'm not entirely sure pics should have happened, so I won't be identifying. 30-Nov-20 07:19 PM Anyway, love the radioactive tape, will be getting some soon 30-Nov-20 07:19 PM Oh, it's Mg-26 onto U-238 30-Nov-20 07:19 PM And I didn't know you could have an ECR ion source producing heavy ion beams at high charge states, pretty neat! 30-Nov-20 07:53 PM You certainly can. 30-Nov-20 11:22 PM RADIOCHEMISTRY SPEEDRUN 30-Nov-20 11:22 PM that sounds like so much potential funstration 30-Nov-20 11:38 PM In general, this is a methods section in a text book I would like to read more of. 30-Nov-20 11:48 PM A U-238 target sounds a lot cheaper and safer and easier to get and handle than a Cf target 30-Nov-20 11:54 PM It's actually just uranium tetrafluoride sputtered onto aluminum foil 01-Dec-20 06:37 AM I suppose you need to have a dedicated sputter system? Because once you do that you’re never gonna get all the radioactivity cleaned out of the chamber 01-Dec-20 06:37 AM I was looking into running ThF4 sputtering for an infrared coating ... but I think it will be much easier to try some alternative like YF3 or YbF3, in a department that has no use of radioactivity, no HP, no training, no detectors etc - it’s just a pain to add all that stuff for one custom filter 01-Dec-20 06:42 AM With an accelerator like that, sputtering/thermal evap of some natural uranium containing compound is probably not a big issue 01-Dec-20 06:42 AM They probably used DU too 01-Dec-20 06:44 AM Aren’t there supposed to be marks for where that glass pane must be lowered to guarantee adequate inbound airflow? 01-Dec-20 08:25 AM Yes, but that’s more for idle mode of “Lower sash to here when you’re done”. Looking at the hood, I’d say a fairly thorough decon was done before this experiment that may have cost it some stickers and postings. IH team didn’t get a chance to re-mark it before Ralf’s work began. 01-Dec-20 08:38 AM Dang it, I remembered Ghiorso's synthesis for Rf-261 wrong. It wasn't Cf + C, but Cm + O. While curium hangs around a bit longer than californium to work with, I would have started swearing at anyone that handed me that experimental proposal if they didn't also include their excellent decon plan to wrap up their work before they even started. I have cleaned up waaaaay too many curium messes; that stuff just dances through the lab until it coats every surface with contamination. [shakes angryfist] 01-Dec-20 09:04 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_from_2020-12-01_15-24-03-C6DDB.png 01-Dec-20 09:04 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/Screenshot_from_2020-12-01_15-25-40-4F9BD.png 01-Dec-20 09:04 AM trinitite! 01-Dec-20 10:17 AM Nice looking spectra 01-Dec-20 10:17 AM What scintillator? 01-Dec-20 10:19 AM NaI(Tl) 01-Dec-20 10:19 AM with the sample inside the well 01-Dec-20 10:19 AM Ahh a well detector makes more sense 01-Dec-20 10:19 AM Thats a nice result from a NaI(Tl) 01-Dec-20 10:25 AM Yep, according to interspec and maestro I am getting <6.5% FWHM at 662 keV 01-Dec-20 10:25 AM here it was around 6.3 iirc? 01-Dec-20 10:25 AM I got so lucky with this detector 01-Dec-20 10:30 AM mine came with it marked 6.7% but just using soundcard stuff I have never gotten close to that heh 01-Dec-20 10:30 AM Think the best I got was like 8-10% 01-Dec-20 10:39 AM Ouh 01-Dec-20 10:39 AM that's... bad 01-Dec-20 12:12 PM I need to get me some lead and Interspec. 01-Dec-20 12:29 PM agreed 01-Dec-20 02:50 PM I need to get myself a proper MCA 01-Dec-20 02:50 PM Especially once I get the well detector working 01-Dec-20 02:53 PM chanting in the distance pitaya! 01-Dec-20 02:54 PM Probably the cheapest option for good quality 01-Dec-20 02:55 PM cheapest one I could find 01-Dec-20 02:55 PM and @Mason_Yu seems happy with theirs, too 01-Dec-20 03:10 PM [wipes tear] I finally got a researcher's experiment signed off as "Beryllium Exempt" with their fascinating new antimony source. They'll have a nickel fluorescence line from the protective coating on the beryllium, and will need to make the sure that the integrity of that coating is in good shape when they crack it open, but I kept them from accidentally turning their lab into SURPRISE BERYLLIUM WORK AREA!!! All things considered, I'd take another SURPRISE ACCELERATOR over that. 01-Dec-20 03:24 PM antimony is not an element you hear too much about... the Sb symbol for it has always messed with me. 01-Dec-20 03:25 PM Stibium! 01-Dec-20 03:25 PM which means pencil in latin, because antimony occurs in pencil shaped minerals (Some sulfide?) in nature 01-Dec-20 03:25 PM iirc, huge grain of salt 01-Dec-20 03:25 PM HA 01-Dec-20 03:25 PM https://upload.wikimedia.org/wikipedia/commons/0/0a/Harvard_Museum_of_Natural_History._Stibnite._%28Iyo%29_Ehime%2C_Shikoku%2C_Japan_%28DerHexer%29_2012-07-20.jpg Stibinite, also known as antimonite, Sb2S3 01-Dec-20 03:28 PM I almost bought some stibnite a few years ago but decided that as nice as the cluster I wanted was I did NOT need an entire flat of the stuff 01-Dec-20 03:28 PM Looks amazing IRL 01-Dec-20 03:29 PM but it's pretty 01-Dec-20 03:29 PM https://fusor.net/board/viewtopic.php?f=20&t=13170&p=85588&#p85588 It's actually really easy, just gotta work smort 01-Dec-20 04:16 PM You are bad man who should feel bad. 01-Dec-20 04:17 PM By the way, how do you know if a beryllium window is shedding material 01-Dec-20 04:17 PM does it discolor? 01-Dec-20 04:25 PM The detection needs wet method swipes and then some bench chemistry, like most all IH things. With ionizing radiation life is much easier. 01-Dec-20 04:25 PM It doesn't discolor so much as the surface loses luster and looks "dusty" as the BeO powder forms. 01-Dec-20 04:27 PM Thanks 01-Dec-20 04:27 PM Talking to my college’s EHS department and figuring out what we’ll need to do more specifically to make sure we don’t have any issues with windows on old gamma specs shedding dust is kinda high on my spring priority list 01-Dec-20 04:34 PM Do you have some old FIDLER probes? If so, how old? 01-Dec-20 04:34 PM Also, if your college has an understanding with DOE, I recommend sending your swipes to PNNL for processing. Their IH lab has more experience processing them than pretty much anyone else around, other than the in-house people at Boeing. 01-Dec-20 04:37 PM If those look like this, then no thankfully 01-Dec-20 04:37 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-6EF7C.png 01-Dec-20 04:37 PM As for this, I’d need to ask EHS 01-Dec-20 04:39 PM phew 01-Dec-20 04:42 PM Most of my concern involves HPGe detector windows really 01-Dec-20 04:42 PM The random ancient beryllium sheet in the flux foil cabinet has since been properly stored. 01-Dec-20 04:46 PM CURSED RESEARCH OBJECT!!! 01-Dec-20 04:47 PM It was just in an old paper envelope. 01-Dec-20 04:52 PM [hisses] currrrrrrrrsed 01-Dec-20 09:52 PM Oh man I need to get myself some trinitite! Question is how do I acquire it... 01-Dec-20 09:52 PM I am a bit worried about Sb contamination in the lead I'm getting, it's a pretty common additive to roof flashing and so on to make the lead stronger and harder 01-Dec-20 10:12 PM There are places to get it online....or you can visit the rock shop near the entrance to the military base that has a seemingly endless supply of some for sale when you go visit the Trinity open house... Or buy it from one of the sketchy people selling it along the road... Or both of those later two like I did (shockingly all of it seems legit). 01-Dec-20 10:13 PM There is a remarkable amount of it in circulation before the moratorium dropped. 01-Dec-20 10:13 PM The photos I have seen of what is still out there are painful knowing that it is going to keep getting broken up and disturbed by the prairie dogs 01-Dec-20 10:13 PM Apparently the guys with the bulldozers did not do a great job 01-Dec-20 10:13 PM Also just to be clear "sketchy people selling it along the road" = people who were there before anyone showed up with tables set up and who were still there after I left...not completely random people. 01-Dec-20 10:17 PM Let's hope I can make the open house next year 01-Dec-20 10:17 PM Hopefully they have an open house next year 01-Dec-20 10:19 PM After ~10% vanished into random collector hands, the rest got scooped into the two repositories but there's plenty of BB sized pieces to get caught in your shoe tread. That said... 01-Dec-20 10:19 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_2358-628ED.JPG 01-Dec-20 10:20 PM Oh someone I was talking to when I visited a few years ago said that he had gotten permission to go do some survey work in the fenced off area... Showed me some phone pictures of 6" across pieces the prairie dogs were digging up 01-Dec-20 10:21 PM If you peek into the two "pig sty" shelters there are massive platter sized pieces in there. 01-Dec-20 10:23 PM I was lucky enough to acquire a piece of CP-1 graphite that Argonne gives out at ANS meetings 01-Dec-20 10:23 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/s-l1600-88E89.png 01-Dec-20 10:23 PM damn 01-Dec-20 10:23 PM I wish I could have seen inside the shelters...only photos I have seen just show the crates that were put in there somewhat recently 01-Dec-20 10:23 PM But this piece is small enough that I will need a very good gamma spectroscopy set-up to see any potential fission or neutron activation products 01-Dec-20 10:24 PM Oh very cool 01-Dec-20 10:24 PM They still give them out every year though 01-Dec-20 10:24 PM I entered into the raffle this year and was not lucky enough to get it 01-Dec-20 10:25 PM Are the rumors about graphite chunks in the woods around where it was set up true? Been wondering if they are scraps from the fabrication or after it was run (assuming the rumor is true) 01-Dec-20 10:25 PM I think they used to be 01-Dec-20 10:25 PM but the area has since been cleaned up 01-Dec-20 10:26 PM Pretty much all CP-1 graphite was used in CP-2, and then all big "live blocks" got buried/disposed of for sure 02-Dec-20 12:00 AM Supposedly you might be able to find some outside the site fence, including ant hills, where they pick it up while building nests. 02-Dec-20 12:38 AM Regarding that Rich Feldman beryllium cutting - what legislation applies if you work with beryllium in your free time? 02-Dec-20 12:48 AM pretty sure @funranium will visit you personally and show you his best bud spencer moves if he finds anything that could potentially go wrong 02-Dec-20 12:49 AM Poor Rich 02-Dec-20 12:49 AM he did that to himself 02-Dec-20 12:50 AM The “you can quite easily give yourself terminal, irreversible beryllium disease” legislation applies, even notwithstanding the risk to others. 02-Dec-20 01:49 AM why would that be an issue? 02-Dec-20 01:54 AM Neutron activation by a fusor under construction. I am going to have one lead box/castle only, used for x-ray stuff, HPGe, the fusor and a small plasma focus experiment will be partially inside it as well 02-Dec-20 01:54 AM I doubt it will be big problem, but I know it can be an issue especially with HPGe 02-Dec-20 01:55 AM I wouldn’t put a neutron source next to a HPGe detector if at all possible 02-Dec-20 01:55 AM Oh the lead sits on a cart 02-Dec-20 01:55 AM So I basically bring the detector to the lead if that makes sense 02-Dec-20 01:56 AM But yeah, antimony kicks off nice high energy gamma rays 02-Dec-20 01:56 AM make your own SbBe neutron source 02-Dec-20 01:56 AM ahh I see 02-Dec-20 01:56 AM It's completely impractical for me to get multiple hundreds of pounds of lead for every set-up that can produce gammas or x-rays 02-Dec-20 01:57 AM Will you need that heavy of lead shielding on the fusor? 02-Dec-20 01:57 AM No, but possibly it will be necessary for the plasma focus 02-Dec-20 01:57 AM 2-3 mm should do it, depending on the operating voltage 02-Dec-20 01:57 AM Which shares the chamber 02-Dec-20 01:57 AM I'm shooting for 65 kV 02-Dec-20 01:58 AM 100 keV photons have a halv value layer of 110 µm im lead 02-Dec-20 01:58 AM heh, and 65 keV have 151 µm 02-Dec-20 01:58 AM right on the peak 02-Dec-20 01:58 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D6FAD.png 02-Dec-20 01:59 AM The stainless will absorb most of it already, it's not going to be a big problem 02-Dec-20 01:59 AM But I'd hate to disassemble the shielding if I want to use it for the HPGe 02-Dec-20 02:00 AM fair 02-Dec-20 02:01 AM Speaking of which 02-Dec-20 02:01 AM https://www.ebay.com/itm/Spellman-DXR-3000/373361882075 02-Dec-20 02:01 AM Fusor supply? 02-Dec-20 02:01 AM That'd be terrifying lol 02-Dec-20 02:01 AM Pretty sure you can reverse the polarity, but need water cooling on the chamber for this one 02-Dec-20 02:02 AM Wow that’d be fun for so many things 02-Dec-20 02:02 AM (And rather terrifying because i hate to think of what it would do to a human) 02-Dec-20 02:03 AM but if you have that much voltage at your disposal I recommend going with beam on target instead of a fusor 02-Dec-20 02:03 AM fusors are sooo inefficient 02-Dec-20 02:03 AM Ion source is quite difficult to do 02-Dec-20 02:03 AM And you'd have to make your own extractor and suppressor (possibly need another supply) 02-Dec-20 02:04 AM true, but the fact that you don't actally need any beam quality makes it a bit easier 02-Dec-20 02:04 AM Then you might only get like 5 mA of beam current 02-Dec-20 02:04 AM 5 mA would be quite impressive already actually 02-Dec-20 02:04 AM yeah, if you're going for high current it will be a pain, but from what I gathered a bot in the µA range has about the same output as a fusor with a few orders of magnitude higher current 02-Dec-20 02:05 AM But that with a Ti coated target would get you beyond any fusor 02-Dec-20 02:05 AM I may or may not be working on a Ti target BOT atm 02-Dec-20 02:05 AM I think a more reasonable intermediate is to just inject your fusor with your ion source 02-Dec-20 02:05 AM Oh! What substrate are you using? 02-Dec-20 02:06 AM just a piece of Ti 02-Dec-20 02:06 AM spot welded onto a 200V zener so the cup around the target can act as a supressor 02-Dec-20 02:07 AM And how are you planning to build the ion source? 02-Dec-20 02:07 AM penning 02-Dec-20 02:07 AM Helicon? Or something fancier? 02-Dec-20 02:08 AM hoping that that will give a high enough ion density 02-Dec-20 02:08 AM maybe ICP, but with my HV sources the ion source has to be at high voltage 02-Dec-20 02:08 AM https://www.rapp-instruments.de/Beschleuniger/neugen2/neugen2.htm This guy built a BOT with a dc discharge ion source 02-Dec-20 02:11 AM Wow that is impressively simple 02-Dec-20 02:11 AM that's what I'm aiming for 02-Dec-20 02:12 AM You don't have to float your ion source at that high of a voltage though 02-Dec-20 02:12 AM I know, but my voltage source for this is an old x-ray transformer with a grounded center tap 02-Dec-20 02:13 AM Oh, even more terrifying than that spellman 02-Dec-20 02:13 AM does up to 100 kV between the outputs, but they have to be symmetrical 02-Dec-20 02:13 AM https://www.youtube.com/watch?v=8ecDhs2V_fU Yep 02-Dec-20 02:14 AM Is that supposed to be in oil or not? 02-Dec-20 02:14 AM it is under oil but feeds the hv to the outside 02-Dec-20 02:14 AM for some reason the tube was in open air 02-Dec-20 02:15 AM Ah so the tank is sideways 02-Dec-20 02:15 AM yeah 02-Dec-20 02:19 AM What voltage did you get up to for your fusor? 02-Dec-20 02:19 AM You used your spark plug feedthrough for it right? 02-Dec-20 02:19 AM back when I was working on the fusor I only had a 30 kV supply 02-Dec-20 02:19 AM yeah, but I got a "real" feedthrough by now 02-Dec-20 02:20 AM Oh pics please? 02-Dec-20 02:20 AM of the feedthrough? 02-Dec-20 02:20 AM Yeah, I'm trying to find a good design that's right for a 8" CF flange 02-Dec-20 02:20 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-E71B3.png 02-Dec-20 02:21 AM Hmm, that won't stand off 65 kV though... 02-Dec-20 02:21 AM lol no way 02-Dec-20 02:21 AM also this is on its way to me I think (hope) 02-Dec-20 02:21 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-3BC74.png 02-Dec-20 02:21 AM Yeah looks like I'm clamping a quartz tube in o-rings 02-Dec-20 02:21 AM Kinda like the quick connect designs, but much larger 02-Dec-20 02:22 AM also I used just a piece of POM KF tube as feedthrough 02-Dec-20 02:22 AM I don't have a lathe 02-Dec-20 02:22 AM I bough it 02-Dec-20 02:23 AM They sell this? 02-Dec-20 02:23 AM https://www.novotek-vacuum.com/small-flange-components-kf/small-flange-branching/joint-pom/ in germany they do 02-Dec-20 02:23 AM Oh pretty neat! 02-Dec-20 02:25 AM even the kf16 one held the 30 kV without any issue 02-Dec-20 02:25 AM although I suppose it was pushing the electrical field limits a bit 02-Dec-20 02:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/file-B16AE.png 02-Dec-20 02:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/file-505AC.png 02-Dec-20 02:25 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/file-3A626.png 02-Dec-20 02:28 AM So the in vacuum ceramic is what? Macor? 02-Dec-20 02:29 AM some alumina tube from aliexpress 02-Dec-20 02:30 AM Yeah if I had a lathe this would be a lot easier, though I still need to find the 8" CF flange that has the right ports for this purpose 02-Dec-20 02:30 AM I'd also need to get myself a spot welder 02-Dec-20 02:30 AM Or a brazing set-up 02-Dec-20 02:31 AM https://www.youtube.com/watch?v=KU1e-zq9hrw 02-Dec-20 02:31 AM may not be great and I'm not sure I'd trust it with batteries, but for metal to metal it sould work just fine 02-Dec-20 02:32 AM Hmm that's just a bit too sketchy for me... There are many commercial spot welders for not that much money 02-Dec-20 02:33 AM but where's the fun in that 02-Dec-20 02:37 AM Well it would be pretty fun actually, when I have a MOT to hand 02-Dec-20 02:40 AM it amazes me how different the maker / hacker communities are 02-Dec-20 02:40 AM here a mot is like the first thing you get, play around a bit with the HV and then gut it, rewind it and build a power supply or something 02-Dec-20 02:40 AM that's how 80% of the people start in germany 02-Dec-20 02:44 AM Ha, back home it's "do the math before you build the thing" 02-Dec-20 02:44 AM And forget about MOTs, I know makerspaces which bans them completely 02-Dec-20 02:45 AM whaaat 02-Dec-20 02:45 AM mots, dsts and nsts! 02-Dec-20 02:45 AM I don't think I know anyone who doesn't have at least three of each XD 02-Dec-20 02:45 AM sure, they're dangerous as all hell but I've never heard of anyone actually getting hurt by them 02-Dec-20 02:49 AM I did hear a few stories, which lead to the ban on NSTs and MOTs 02-Dec-20 02:50 AM geez 02-Dec-20 03:11 AM What does DST stand for? I always wanted a NST, they seem rarer and rarer, I’ve never actually seen one in person 02-Dec-20 03:15 AM diode split transformer 02-Dec-20 03:15 AM the ones in crt tvs that output dc 02-Dec-20 03:15 AM NSTs are slowly being replaced by HV SPMS with are too sensitive to be used by eg. a tesla coil 02-Dec-20 03:15 AM and neon signs in general are being replaced by leds 02-Dec-20 03:15 AM we used to have loads of iron core NSTs at the scrapyard, but now we can't go to the scrapyard 02-Dec-20 06:53 AM https://paglen.studio/2020/01/21/trinity-cube/ huh 02-Dec-20 07:20 AM Those are much beefier than the SHV 20kV feedthroughs 02-Dec-20 07:47 AM With respect to what regs apply for beryllium, it depends what you would like to do in your free time with your toxic materials. In America, you get to take your pick of hazardous substance controls from a variety of different agencies at the local, state, and federal level. The ones most applicable are your local air quality district, RCRA for hazardous waste (as household waste people generally want nothing to do with you), and likely most impactful you have to make a disclosure that a space on your property has a Beryllium Work Area. If you are renting your place, you likely just violated your lease and have royally screwed your landlord. They will sue you for damages. This is in addition to the punishment Be itself will dole out to you. There's a reason the average life expectancy of chemical engineers used to be 45: boiling crucibles of BeO. 02-Dec-20 01:38 PM What is a MOT? 02-Dec-20 01:38 PM @Mason_Yu did you win that graphite, or was it an eBay acquisition? 02-Dec-20 01:40 PM Microwave oven transformer 02-Dec-20 01:43 PM Ahhh. I know someone who salvages them out of microwaves and remakes them into kits for Lichtenberg wood burning. 02-Dec-20 01:47 PM I would not feel safe selling kits like that. 02-Dec-20 01:47 PM People kill themselves doing Lichtenberg figures because they don't respect the 2kV at 500mA 02-Dec-20 01:47 PM same 02-Dec-20 02:30 PM Yeah a NST is one thing, but MOTs aren't what I would call current limited. 02-Dec-20 02:34 PM I get jittery around MOTs 02-Dec-20 02:34 PM 50 Hz jittery? 02-Dec-20 02:34 PM no 02-Dec-20 02:34 PM more like 02-Dec-20 02:35 PM Only thing I would personally use a mot for is to re wind the secondary for service in an evaporator 02-Dec-20 02:35 PM if you touch the thing when powered it will more than megahertz jittery 02-Dec-20 03:23 PM I’ve also seen them wired backwards on YouTube to make low voltage at massive current. Used as DIY arc welders. 02-Dec-20 03:25 PM rewound, not backwards, right? 02-Dec-20 03:32 PM Both unfortunately 02-Dec-20 03:32 PM Rewond is ofc what you want if you don't want to melt down the primary 02-Dec-20 06:27 PM It was an eBay acquisition 02-Dec-20 06:28 PM I am glad it went to a good home. I thought I saw it on eBay last week. 02-Dec-20 06:28 PM I have a block as well. 02-Dec-20 06:28 PM As far as I know, it is only possible to win CP-1 graphite either as a long term Argonne employee or get very lucky at ANS meetings 02-Dec-20 06:28 PM That or estate sales 02-Dec-20 06:29 PM eBay for mine. 02-Dec-20 09:17 PM @Mason_Yu well I finally got the whole thing apart and at the very least I'm now certain it can be repaired. The detector tube, the one thing I wasn't sure about being replaceable is something LND still makes. 02-Dec-20 09:18 PM Is it just filled with air? 02-Dec-20 09:18 PM And you've confirmed it's dead? If so, how did the tube meet its demise? 02-Dec-20 09:18 PM propane 02-Dec-20 09:18 PM no I wasn't sure it was dead 02-Dec-20 09:18 PM but I wasn't sure if it had failed somehow or if there was a different issue 02-Dec-20 09:18 PM I still haven't tested the JFET 02-Dec-20 09:20 PM I don't know what the gain on the differential amplifier is, so the voltage from the JFET might be really low 02-Dec-20 09:20 PM I guess you should put your strongest source right next to the tube and make sure high voltage is at the higher end of its operation range 03-Dec-20 11:30 AM https://www.gammaspectacular.com/phpBB3/viewtopic.php?f=14&t=885&sid=2d018a2041c067887b4445fb3a665e7a 03-Dec-20 11:32 AM Impressive, both in results and in the price 03-Dec-20 11:33 AM Sigh... 03-Dec-20 11:33 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-DDC54.png 03-Dec-20 11:33 AM I mean 03-Dec-20 11:33 AM it's cheap for what it is 03-Dec-20 11:33 AM but it is a lot 03-Dec-20 11:34 AM More than twice what I paid for two HPGe detectors... 03-Dec-20 11:34 AM but did you get them new and in perfectly working order? 03-Dec-20 11:34 AM it's just two different use cases imo 03-Dec-20 11:34 AM you could order a few 100 of those SrI and build a 4 pi detector 03-Dec-20 11:36 AM I know it's not a perfectly fair comparison, but I think this is a better value: http://maximus.energy/index.php/2020/11/01/capesym-scinticlear-sc-14x2-sipm-gamma-detector/ 03-Dec-20 11:36 AM the 2 mm is a no go for me imo 03-Dec-20 11:37 AM Well for really high energy stuff, NaI should be okay 03-Dec-20 11:37 AM you don't need really high energy stuff to get to its limits, just look at that 662 keV peak 03-Dec-20 11:37 AM you'd need lots of lifetime to see co60 eg. 03-Dec-20 11:37 AM an imo the advantage of a small device is that it can be carried for field measurements 03-Dec-20 11:37 AM and then having to wait hours in the field is... eh 03-Dec-20 11:37 AM ^^ 03-Dec-20 11:39 AM Always painful when you hear "relatively inexpensive" used in that context 03-Dec-20 11:39 AM Sorta like "contact for price" 03-Dec-20 11:41 AM I have the same issue with my LaBr, it's a very nice detector but the useable range is just to ~1 MeV at best 03-Dec-20 11:41 AM It doesn't look like they sell the SrI2(Eu) crystal on its own 03-Dec-20 11:41 AM But they do sell fairly big CLYC(Ce) crystals 03-Dec-20 11:42 AM they sell 1x1" SrI 03-Dec-20 11:42 AM but I'd rather get a car 03-Dec-20 11:42 AM Me too lol 03-Dec-20 11:42 AM I've been saving up for like two years, and every time something gets in the way 03-Dec-20 11:42 AM Guess I'd have to save up for another two months 03-Dec-20 11:45 AM if all goes well I'll have my licese next tuesday 03-Dec-20 11:45 AM and for now I can use my parenty car 03-Dec-20 11:45 AM so much more range to pick up stuff 03-Dec-20 11:30 PM RIP this crystal. (Found it in a bin of junk at work) 03-Dec-20 11:30 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-BC234.jpg 03-Dec-20 11:31 PM at first glance I got quite a shock, thinking that you got mail 03-Dec-20 11:31 PM advertise it as polyscin, lol 03-Dec-20 11:31 PM It went right back into the “broken stuff to give out to staff at meetings” bin 04-Dec-20 12:41 AM https://www.researchgate.net/publication/231121614_Bismuth-loaded_plastic_scintillators_for_gamma-ray_spectroscopy 04-Dec-20 12:51 AM I’m actually going to be using triphenyl bismuth with a liquid scintillator next week 04-Dec-20 12:51 AM But that’s just because I’m doing analysis of bismuth and that was on hand 04-Dec-20 12:52 AM rightm you were doing some Bi loaded stuff 04-Dec-20 12:52 AM wanna see if you can get a spectrum out of it? 04-Dec-20 12:53 AM Maybe, but now that I think about it, this could screw up quench correction 04-Dec-20 12:53 AM also, I'm reading a lot int organic scintillators at the moment, trying to learn about them. Can you tell me what cocktail you use? 04-Dec-20 12:53 AM It’s going to be a mix of cocktails 04-Dec-20 12:53 AM You looking for specific ones or general details 04-Dec-20 12:54 AM mostly learning what primary and secondary fluor go well with what solvent etc 04-Dec-20 12:54 AM Ah, I’m not 100% sure in that regard 04-Dec-20 12:54 AM Most of what I’ve been looking at has been with data processing, spectrum deconvolution and alpha beta separation 04-Dec-20 12:56 AM ahh, ok :D 04-Dec-20 12:56 AM I am trying to mix my own, without killing myself or having access to sigma etc 04-Dec-20 12:57 AM ah, hm 04-Dec-20 12:59 AM I am hoping that the emission of p-terphenyle is close enough to a bialkali pmt that I can get any signal at all 04-Dec-20 12:59 AM that's my first goal for now :D 04-Dec-20 12:59 AM hopefully 04-Dec-20 01:04 AM thanks for the pdf in #resources 04-Dec-20 01:07 AM happy to share it, I've got a massive folder of LSC related papers and things at this point from my thesis 04-Dec-20 01:19 AM but yeah, the bismuth potentially screwing up the normal quench correction method is something I hadn't thought about and now might be a pain 04-Dec-20 01:19 AM thankfully the final plan is to do it with insoluble compounds 04-Dec-20 01:21 AM how would that work? 04-Dec-20 01:27 AM suspension in a gel basically 04-Dec-20 01:27 AM ultrasonication and then cooling like you're making jello 04-Dec-20 01:28 AM turns out I've been making jello wrong all my life, not using an ultrasonicator 04-Dec-20 01:28 AM lol 04-Dec-20 01:28 AM doesn't that screw up the transparency? 04-Dec-20 01:30 AM to a degree yes, but hopefully I won't need enough sample to really be too big an issue 04-Dec-20 01:31 AM ah I see 04-Dec-20 01:31 AM good luck 04-Dec-20 01:31 AM thanks 04-Dec-20 01:31 AM First irradiation is next week to give me a month for the polonium to build up 04-Dec-20 01:32 AM can you say anything about the goal of the experiment? 04-Dec-20 01:33 AM trying to do NAA on a bismuth phosphate organic complex 04-Dec-20 01:34 AM ahh neat 04-Dec-20 01:35 AM thanks 04-Dec-20 01:35 AM kinda 2.5 ways to do it as far as I can tell, deconvolution of 32P and 210Bi beta spectra, separation of 32P betas and 210Po alphas, or measuring phosphorus by INAA with the neutron alpha fast neutron reaction producing 28Al and then alpha particle counting of 210Po after the 32P decays off 04-Dec-20 01:38 AM inaa? 04-Dec-20 01:39 AM NAA then decay gamma counting without any chemistry 04-Dec-20 01:39 AM normal NAA 04-Dec-20 01:39 AM instrumental neutron activation analysis 04-Dec-20 01:40 AM oh, ok 04-Dec-20 01:40 AM as opposed to lsc stuff which involves chemical processing of the samle? 04-Dec-20 01:42 AM Normally as opposed to radiochemical separation after irradiation to separate out interfering nuclides or nuclides of interest 04-Dec-20 01:43 AM ahh 04-Dec-20 01:46 AM yeah, I need to turn in for the night. If you have other questions on LSC stuff, I'm more than happy to do my best to answer any of them 04-Dec-20 01:47 AM thanks, and have a good night ^^ 04-Dec-20 01:49 AM thanks 04-Dec-20 10:50 AM Sandia: Sand-ja Sandy-ah San-Dia? 04-Dec-20 10:57 AM San-dja 04-Dec-20 10:57 AM S-and-ia 04-Dec-20 11:15 AM huh 04-Dec-20 11:25 AM @GigaSquirrel what was the thing that was too expensive that you posted about on twitter? 04-Dec-20 11:25 AM some fluor named FIrPIC 04-Dec-20 11:25 AM organometallic iridium complex 04-Dec-20 11:25 AM https://www.ossila.com/products/firpic 04-Dec-20 11:25 AM apparently bismuth makes the normal fluors worse (quenches them?), but not that one 04-Dec-20 11:25 AM allowing absurdly high Bi content, in the paper I posted above it was 40% by weight Bi and ~31k ph/MeV 04-Dec-20 11:28 AM not which on? 04-Dec-20 11:28 AM the iridium complex? 04-Dec-20 11:28 AM yeah, the Ir complex works well with Bi 04-Dec-20 11:28 AM this paper 04-Dec-20 11:28 AM also apparently the matrix they use is some conductive polymer that costs around $10 per gram on sigma 04-Dec-20 11:28 AM so yeah, it's full of a whole load of black magic 04-Dec-20 11:39 AM ah blegh 04-Dec-20 11:39 AM I do wonder how a triphenylbismuth loaded liquid scintillator will work 04-Dec-20 11:39 AM only one way to find out 04-Dec-20 11:41 AM there was some other Bi compound I found in other papers that apparently also works well 04-Dec-20 11:41 AM one sec 04-Dec-20 11:41 AM Bismuth Tripivalate 04-Dec-20 11:41 AM maybe that's cheaper 04-Dec-20 11:41 AM it mainly looks less optically active and might mess less with your cocktail 04-Dec-20 11:50 AM looks like it would be fairly straightforward to synthesize 04-Dec-20 11:50 AM start with 2,2-dimethylpropanol, oxidize that to 2,2-dimethylpropanoic acid, then form the bismuth complex 04-Dec-20 11:53 AM Ah, yes, those are words 04-Dec-20 11:53 AM I never got above high school chemistry, and at uni we're back to "this is an ionic bond, this is a molecular bond" 04-Dec-20 11:53 AM 'tho iirc you can oxidise primary alcohols to acids, secondary alcoholes to ketones and tertiary to some others? 04-Dec-20 11:53 AM but how would one do said oxidation? 04-Dec-20 11:57 AM might be able to do it with a basic aqueous permanganate solution 04-Dec-20 11:59 AM basic as in simple or as in high ph? 04-Dec-20 11:59 AM high ph 04-Dec-20 11:59 AM but it's a nicer oxidizing agent 04-Dec-20 12:01 PM oh, I see 04-Dec-20 12:01 PM and then how do you make the Bi an organometallic complex instead of just a salt of that acid? 04-Dec-20 12:03 PM probably would be the hardest part 04-Dec-20 12:03 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-6F6A5.png 04-Dec-20 12:05 PM oh 04-Dec-20 12:05 PM so that's why bismuth nitrate is so common I guess 04-Dec-20 12:18 PM possibly 04-Dec-20 01:23 PM https://www.osti.gov/servlets/purl/1543075 This, p. 15ff suggests nanoparticles instead of organometallics to get around the quenching issue 05-Dec-20 02:15 AM hmm I should try boron loading 05-Dec-20 02:15 AM I am just collecting ideas at this point until I get all the chemicals to actually try something 05-Dec-20 07:33 PM “New” meter 05-Dec-20 07:33 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-44D86.jpg 05-Dec-20 07:49 PM Oooo, a classic control point monitoring box. 05-Dec-20 07:57 PM yep, a properly old one too, with the weird power connector 05-Dec-20 08:54 PM Today is new detector day for me too 05-Dec-20 08:54 PM Unfortunately for me, looks like I've got a partially broken detector 05-Dec-20 08:54 PM He-3 tube inside an identifinder 05-Dec-20 08:54 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201205_225443-33EF7.jpg 05-Dec-20 08:54 PM With something rattling inside 05-Dec-20 08:54 PM There are spot welds near the end, presumably the end insulator post has come loose 05-Dec-20 08:54 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201205_225622-2C1CC.jpg 05-Dec-20 08:54 PM Well at least I know what I will use as the subject for my first x-ray radiograph... 05-Dec-20 09:55 PM New broken meter day for us both then 05-Dec-20 09:55 PM Darn shame about the 3He tube, that sounds like a royal pain to replace 05-Dec-20 10:21 PM Yeah... It's very possible I'll have to make a feedthrough and connect it to an external tube, don't know if I can find a He-3 tube with the right voltage that's this small 05-Dec-20 10:21 PM https://www.ebay.com/itm/Russian-Geiger-NEUTRON-Counter-SNM-13-SNM13-NEW-LOT-1/163973115979 05-Dec-20 10:21 PM These will fit, but are corona tubes with much lower operating voltage than the He-3 tube at 8 atm originally in the identifinder 05-Dec-20 10:56 PM and they're absolutely blind 05-Dec-20 10:57 PM Actually, are there any Russian He-3 tubes on eBay that's not a corona tube? 05-Dec-20 10:57 PM https://www.ebay.com/itm/High-Sensitivity-Helium-3-He-3-Neutron-Detector-Proportional-Counter-Tube-SNM-56/143799415799 05-Dec-20 10:57 PM Ah there's this one 05-Dec-20 11:07 PM there are a few proprotional He3, and the snmo5 is proprotional bf3 05-Dec-20 11:09 PM The plateau voltage on the SNM-56 is slightly too high for the identifinder though 05-Dec-20 11:15 PM tbh, all the russian tubes are kinda... eh 05-Dec-20 11:15 PM they will give you a signal and survive a nuclear blast, but they're not exactly sensitive and the corona mode isn't great for longevity 05-Dec-20 11:15 PM and the data you can find about them is sparse at best 05-Dec-20 11:16 PM Yeah many are rated for only 500 hours of operational life 05-Dec-20 11:16 PM http://www.quartz1.com/price/techdata/Priemniki_i_detektory_izluchenij_2012.pdf 05-Dec-20 11:16 PM Use Google Lens or other translation software on this 05-Dec-20 11:16 PM I know that pdf, but I'd like to know things like... what's actually inside 05-Dec-20 11:16 PM BF3, HE3, Argon and boron coated wall? 05-Dec-20 11:16 PM fill pressure 05-Dec-20 11:16 PM some information on what some rows in those charts actually mean 05-Dec-20 11:28 PM They do specify if the detector is boron coated or if it is a corona tube on the second column: "Design features, cathode, purpose". And I think the series acronym indicates the fill gas 05-Dec-20 11:28 PM No idea where you can find the fill pressure without having the specific datasheet for that detector though 05-Dec-20 11:29 PM what do you mean by "series acronym"? 05-Dec-20 11:30 PM SNM, SI and so on 05-Dec-20 11:30 PM ah, no 05-Dec-20 11:30 PM I have SNM tubes that are both boron (SNM11) and He3 (SNM18), corona (11 and 18) and proportional (snm-18-1, snm-3) 05-Dec-20 11:30 PM I honestly could not find any method to their madness 05-Dec-20 11:32 PM Hmm, SNM-11 is boron-coated on steel cathode according to the table 05-Dec-20 11:33 PM my Si19n are He3 corona, my Si10n is proportional, but no idea about the active ingredient 05-Dec-20 11:33 PM I don't think it's He3, because it has some pretty thin glass walls 05-Dec-20 11:33 PM is there a list of which is which anywhere? or is it just random 05-Dec-20 11:33 PM correct 05-Dec-20 11:33 PM sounds like the power channels at the reactor 05-Dec-20 11:33 PM apparently just random, but the pdf mason posted gives hits 05-Dec-20 11:33 PM Ah 05-Dec-20 11:34 PM Yeah it requires some detective work... 05-Dec-20 11:34 PM if I had a decent neutron source I'd just take spectra 05-Dec-20 11:34 PM I've been tempted to grab a proportional tube or two while they pretty available 05-Dec-20 11:35 PM You can also search in Russian and there are more info on Russian forums 05-Dec-20 11:35 PM tried that, but in my experience it doesn't lead very far 05-Dec-20 11:36 PM https://www.ebay.com/itm/Helium-3-He-3-High-Sensitivity-Neutron-Counter-Tube-Proportional-Detector-Si19N/274329419180 05-Dec-20 11:36 PM These are the cheapest proportional tubes I can find 05-Dec-20 11:36 PM they are about the cheapest that are out there, He3 and corona 05-Dec-20 11:36 PM https://consensus-group.ru/radiation-counters/neutron-counters/corona-counters/209-snk-30200-46om That's their modern day equivalent, looks like they're not too different 05-Dec-20 11:38 PM Hmm now I'm super confused 05-Dec-20 11:38 PM How is Si19-N corona? I don't see a Коронный specification for it on the table 05-Dec-20 11:39 PM there's a seller on ebay claiming that the corona tubes can be used in proportional mode, and many others just copy their description 05-Dec-20 11:39 PM but they have terrible gain 05-Dec-20 11:39 PM but it specifies a corona ignition voltage, and a voltage range to use them at a voltage above that ignition voltage 05-Dec-20 11:39 PM third row says Напряжение начала счета или (зажигания короны), В , Counting start voltage or (corona ignition), V 05-Dec-20 11:44 PM Are we looking at different tables? You are referring to СИ-19Г and I'm looking at СИ-19Н 05-Dec-20 11:45 PM huh? 05-Dec-20 11:45 PM SI19N is the СИ-19Н 05-Dec-20 11:45 PM page 45 05-Dec-20 11:45 PM The table for СИ-19Н gives Протяженность плато счетной характеристики, В, не менее, or The length of the plateau of the counting characteristic, V, not less 05-Dec-20 11:45 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-EDF61.png 05-Dec-20 11:45 PM Yeah 4th column 05-Dec-20 11:46 PM ohh, yeah, because the corona discharge ignites ate 1600-1750 but you want to drive it somewhat above the ignition voltage 05-Dec-20 11:46 PM you drive them with ~47M in series, the "burning voltage" across the tube stays somewhat the same, but with higher driving voltage it draws more current 05-Dec-20 11:48 PM Ahh, but why do they specify a counting plateau for a tube designed for corona discharge above 2000 V? I guess it basically means the range of operation for the tube, rather than a literal plateau 05-Dec-20 11:48 PM yep 05-Dec-20 11:48 PM exactly 05-Dec-20 11:49 PM Again, just really confusing stuff... 05-Dec-20 11:49 PM yep 05-Dec-20 11:49 PM exactly 05-Dec-20 11:49 PM there is madness to their method 05-Dec-20 11:51 PM Well the spectrum showed by Maximus energy looks not so good, and he claims it is still a spectroscopy-grade detector 05-Dec-20 11:51 PM Spectroscopy?? 05-Dec-20 11:51 PM he claims some wild things about how to operate them tbh 05-Dec-20 11:51 PM https://www.ebay.com/itm/Ultra-High-Sensitivity-Helium-3-He-3-Neutron-Detector-Proportional-Counter-Tube/143720244127 05-Dec-20 11:51 PM not sure how this is supposed to be a neutron spectrum 05-Dec-20 11:51 PM it's just a He3 spectrum, wall effect and all 05-Dec-20 11:51 PM you'd need to get way more complicated to get a neutron spectrum 05-Dec-20 11:52 PM Bring in the spheres 05-Dec-20 11:52 PM hehe 05-Dec-20 11:53 PM I think by spectroscopy grade, he just means you can see the full energy peak and the wall effect plateau (even that's a stretch) 05-Dec-20 11:53 PM Some of the entries for other He-3 tubes in the table also specifies "spectroscopy grade", with better results than this one presumably 05-Dec-20 11:53 PM You can tell if you have a fast neutron component by looking at counts beyond the full energy peak 05-Dec-20 11:53 PM But yeah, you need really fast neutrons, and even then you won't really have any quantifiable accuracy with this method 05-Dec-20 11:55 PM but you need proportional for that, corona gives you no way of getting any spectroscopic information 05-Dec-20 11:55 PM I guess? That’s hella weird advertising 05-Dec-20 11:56 PM With the Si-19N operating in "proportional" mode below 2000V, maybe it's possible? 05-Dec-20 11:57 PM I haven't tried the Si19n specifically, but both snm11 and snm18 are "impossible" to operate in proportional, as they are microphonic as all hell, and have minimal gain 05-Dec-20 11:57 PM in the order of <50 iirc 05-Dec-20 11:58 PM 50? 05-Dec-20 11:58 PM The eyebrow raise at doing any spectroscopy with these is approaching hairline. 05-Dec-20 11:58 PM gas gain of 50 05-Dec-20 11:58 PM Ah 05-Dec-20 11:59 PM or less 05-Dec-20 11:59 PM That’s a fancy ion chamber 05-Dec-20 11:59 PM I guess these are pretty leaky then 05-Dec-20 11:59 PM Experience with these and similar is not great. The neutronics equivalent of a GM. 05-Dec-20 11:59 PM leaky? 06-Dec-20 12:00 AM I doubt they still have the original 4 atm of He-3 06-Dec-20 12:00 AM that's a very good way to describe it. They detect neutrons, but that's about it 06-Dec-20 12:00 AM Because if they do, the gas gain would be much higher 06-Dec-20 12:00 AM ah, actually, mine were either completley dead or still well within their corona ignition voltage and current range 06-Dec-20 12:00 AM the gain also depends on anode geometry, and I guess they just have a thick anode inside 06-Dec-20 12:01 AM That's just physics, unless they have some really strange detector geometry 06-Dec-20 12:01 AM Why would they make a super thick anode though? 06-Dec-20 12:01 AM For resistance to mechanical shock? Doesn't take that thick of a wire to do that 06-Dec-20 12:02 AM ease of manufacutre, mechanical stability? 06-Dec-20 12:02 AM I should open one of my dead ones 06-Dec-20 12:02 AM ^ 06-Dec-20 12:03 AM I've been putting that off as I'm not sure how much He3 is still left in them and I thought about recovering that somehow 06-Dec-20 12:03 AM some kind of vampire tap and a small pump 06-Dec-20 12:03 AM but I haven't put much thought into it yet 06-Dec-20 12:04 AM I ought to check if there any busted BF3 tubes in the junk bin at work. 06-Dec-20 12:04 AM @GigaSquirrel X-ray it! 06-Dec-20 12:04 AM You have a friend who can do that right? 06-Dec-20 12:04 AM That I would not recommend cracking into. 06-Dec-20 12:04 AM the x-ray I have access to has ~1.6 mm focal spot iirc 06-Dec-20 12:04 AM Toxicity? 06-Dec-20 12:05 AM but I know someone with a microfocus 06-Dec-20 12:05 AM I should send them a tube 06-Dec-20 12:05 AM BF3 is quite toxic which is why you have to declare them for flights. 06-Dec-20 12:05 AM methinks you're trying to tell me something 06-Dec-20 12:05 AM I mean I'd love to, but shipping to the USA takes months atm, and shipping cost is about the same as just buying another detector 06-Dec-20 12:06 AM Ok I just re-skimmed hazards, yeah, and I’m going to also make sure that none end up going into the “broken junk for meetings” bin 06-Dec-20 12:07 AM Yeah I get it, I have a few mystery detectors acquired from China too and I definitely will x-ray them 06-Dec-20 12:07 AM Thank you for doing yourself and your institution a service. Also, there tend to be interesting coatings in there. 06-Dec-20 12:07 AM Coatings? 06-Dec-20 12:08 AM Things to keep the BF3 from eating the components. 06-Dec-20 12:08 AM Ah, right 06-Dec-20 12:09 AM mystery detectors from china? Tell me more! 06-Dec-20 12:12 AM They look like one of the J-series halogen GM tubes, but no marking on them whatsoever 06-Dec-20 12:12 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201206_021158-C418E.jpg 06-Dec-20 12:12 AM heh 06-Dec-20 12:12 AM Oh interesting 06-Dec-20 12:12 AM the big one looks like one of the tubes I have 06-Dec-20 12:12 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/p1030936-FB646.png 06-Dec-20 12:12 AM has markings on it, still can't find anything about it 06-Dec-20 12:13 AM Yeah it's either J306 or J308? 06-Dec-20 12:13 AM https://www.aliexpress.com/i/4000859462326.html 06-Dec-20 12:14 AM ah, thanks 06-Dec-20 12:14 AM should be easy to measure, they're very different in size 06-Dec-20 12:14 AM also wth is the j302 06-Dec-20 12:16 AM Ah measuring the dimensions, it's a J308 and a J307 06-Dec-20 12:16 AM Well that solves that mystery 06-Dec-20 12:17 AM no plateau and >150 hr spec 06-Dec-20 12:19 AM I feel like 150 might be a dropped exponent somewhere but even that doesn’t make sense 06-Dec-20 12:19 AM it specifically says hour 06-Dec-20 12:19 AM background in time per minute 06-Dec-20 12:19 AM No damn clue then 06-Dec-20 12:20 AM heh, that's usually 60 s 06-Dec-20 12:23 AM Hm, would be interesting to just get one and track the count output over a few weeks of it being exposed to a decently large source 06-Dec-20 12:24 AM drop it in the reactor! 06-Dec-20 12:25 AM Well cables would be hard in that case 06-Dec-20 12:25 AM I’d want to have hv on it the whole time 06-Dec-20 12:26 AM that's an easy way to build a neon bulb 06-Dec-20 12:26 AM lol 06-Dec-20 02:51 AM @GigaSquirrel Did you confirm if your SI-10N tube is proportional He-3? 06-Dec-20 02:52 AM nope 06-Dec-20 02:52 AM I am fairly certain it's not He3 06-Dec-20 02:52 AM must be some low pressure fill 06-Dec-20 02:52 AM Ah, really low sensitivity? 06-Dec-20 02:53 AM I can't actually determine sensitive, due to the lack of a neutron source 06-Dec-20 02:53 AM I thought you did some tests last year when you had access to a neutron source 06-Dec-20 02:53 AM Or maybe I'm remembering wrong 06-Dec-20 02:53 AM yeah, but back then I didn't have the si10n 06-Dec-20 02:53 AM and now I no longer have access to that source 06-Dec-20 02:54 AM Hmm, I've just confirmed I need to replace the beryllium window on my HPGe 06-Dec-20 02:54 AM Am-Be source? 06-Dec-20 02:54 AM Maybe... 06-Dec-20 02:55 AM but it has a fairly thin glass stalk on the anode side, that definitely doesn't look like high pressure 06-Dec-20 02:55 AM alpha Be sources are very inefficient, around 10^-6, maybe -5 if you mix the source and Be 06-Dec-20 02:55 AM you're in america, right? 06-Dec-20 02:55 AM get one of those Po buttons, not Am 06-Dec-20 02:57 AM It would be easier to sandwich or mix the Am sources from the cheap smoke detectors (legality aside) 06-Dec-20 02:57 AM but you literally need hundreds of kBq or MBq to get any sort of output 06-Dec-20 02:57 AM and those smoke detector sources are 33 kBq iirc? 06-Dec-20 02:57 AM +/- an order of magnitude, but 1 MBq of AmBe will give you about a neutron per second 06-Dec-20 02:58 AM You mean the Po button sources from Spectrum Techniques right? Or some other really high activity Po source? 06-Dec-20 02:58 AM the antistatic ones 06-Dec-20 02:58 AM Oh the static removers 06-Dec-20 02:58 AM https://www.youtube.com/watch?v=uQ8vwevCq8Q 06-Dec-20 02:58 AM that was 185 MBq and barely gets the detector going 06-Dec-20 02:58 AM vacuuming it will give you a somewhat higher output 06-Dec-20 02:58 AM the source I used was 3.7 GBq AmBe with the AmO2 and Be mixed and sintered, that gave ~10^5 n/s 06-Dec-20 03:02 AM I thought about vacuuming, and sealing it inside a smaller package with compaction. The thing is, in terms of cost, Am sources are about the same as the Po sources when you compare the smoke detectors and the rented static removers 06-Dec-20 03:03 AM I strongly advise against taking apart 1000 smoke detectors 06-Dec-20 03:03 AM Yeah, I know... Everything here comes with big asterisks 06-Dec-20 03:03 AM plus I suppose that the source in there is less open 06-Dec-20 03:06 AM I think Carl made another source from Be foil too 06-Dec-20 03:06 AM Struggling to find the video for that at the moment 06-Dec-20 03:06 AM Yep, this one 06-Dec-20 03:06 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-0D078.png 06-Dec-20 03:07 AM yep 06-Dec-20 03:07 AM that's a pretty hot source 06-Dec-20 03:13 AM https://youtu.be/ng6NOH8S7Bk?t=52 "made with many parts of old-fashioned smoke detectors" 06-Dec-20 03:14 AM old fashioned refers to when they were hotter I suppose 06-Dec-20 03:14 AM I don't know how hot they are today in america, I'm just saying that you need a lot of activity 06-Dec-20 03:17 AM Yeah I know, I've done some calculations with the hottest Am sources I can find at ~5 uCi, it would still be cost-prohibitive for me to do this. 06-Dec-20 03:17 AM Since I have half of a working power supply now, it would be easier to build a fusor 06-Dec-20 03:18 AM yep 06-Dec-20 03:18 AM higher output for cheaper 06-Dec-20 03:18 AM Not to mention the legality side of all of this 06-Dec-20 03:18 AM and you can turn it off, and can't contaminate stuff with it 06-Dec-20 03:19 AM Now the challenge is get the other half of the supply working 06-Dec-20 03:19 AM And make the feedthrough 06-Dec-20 03:20 AM Those smoke detectors are probably the Pyrotronics ones 06-Dec-20 03:21 AM I got two decent sized feedthroughs, and how I'm rethinking my ion source 06-Dec-20 03:21 AM I have one out in a corner of my garage that was in a dumpster at a construction site... 06-Dec-20 03:21 AM Kinda wish I left it there but it felt wrong to let that go w/ building debris 06-Dec-20 03:21 AM it was a very good idea to take it 06-Dec-20 03:21 AM @GigaSquirrel What are you thinking? 06-Dec-20 03:22 AM not sure yet tbh 06-Dec-20 03:22 AM a duoplasmatron would be really nice, but then I'd need a heater at hv 06-Dec-20 03:26 AM @LRM But even with those hot 80 uCi sources, it would still not make sense financially compared to the 5 uCi smoke detectors, it would still cost $1000+ to get any decent neutron output, again, legality aside 06-Dec-20 03:26 AM icp / ccp would also be an option, I recently got a great amplifier for that 06-Dec-20 03:26 AM maybe I'll just steal carls ion source 06-Dec-20 03:26 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/ion_source_mod-78DCB.png 06-Dec-20 03:27 AM I do think ICP sources win overall, in terms of consistency and vacuum needs 06-Dec-20 03:27 AM Yep, that, basically 06-Dec-20 03:27 AM 0.9uci usually 06-Dec-20 03:28 AM issue is that that side of the accelerator has to work with positive high voltage against ground 06-Dec-20 03:28 AM so I'd have to rebuild the extractor 06-Dec-20 03:28 AM Your transformer complicates things by a lot 06-Dec-20 03:28 AM The 1960's smoke alarms can be 50-100 uci, they can actually make an x-ray screen light up in a dark room 06-Dec-20 03:28 AM yep 06-Dec-20 03:29 AM Float your amp and the power supply that feeds it and drive it with a belt! 06-Dec-20 03:29 AM I guess a penning source would be easiest to float, as I can just add any high voltage module and a 18650 06-Dec-20 03:33 AM a while ago bob tubbs made a beam on target neutron source 06-Dec-20 03:33 AM https://www.youtube.com/watch?v=DdLe6No5he4 06-Dec-20 03:35 AM I don't know any amateurs who actually made H/D ion sources with helicon tubes 06-Dec-20 03:35 AM All of them operate in the ICP regime 06-Dec-20 03:35 AM But you can get 50% more ion density by jumping to helicon! And that can translate to really massive increases in extracted current 06-Dec-20 03:35 AM It does require some design work of course, and most of the time it's easier to just dump more RF power into it 06-Dec-20 03:38 AM yeah looks like his was ICP https://www.youtube.com/user/U235hexafluoridedude/videos 06-Dec-20 03:39 AM He did get past 1 mA though, an impressive achievement 06-Dec-20 03:39 AM https://www.youtube.com/watch?v=X8kDdwOvZd8&ab_channel=RobertTubbs 06-Dec-20 03:39 AM Wow, this is really neat 06-Dec-20 03:41 AM I tried to get him to join this server but he seems to be a bit antisocial right now 06-Dec-20 03:41 AM it sure is an impressive setup 06-Dec-20 03:42 AM I think bob has been looking for some kind of lab tech job 06-Dec-20 03:42 AM if anyone needs a handy person... 06-Dec-20 03:42 AM Hmm, he'll be a nice fit where I work 06-Dec-20 03:42 AM We basically build his system, but at 60 mA 06-Dec-20 03:42 AM And 1e10 n/s + 06-Dec-20 03:43 AM if you like I could connect you two 06-Dec-20 03:43 AM Please do 06-Dec-20 03:43 AM oh my. What voltage? 06-Dec-20 03:44 AM 180 kV+, not sure if I can share all the specs here 06-Dec-20 03:44 AM ohh wow 06-Dec-20 03:44 AM cw?! 06-Dec-20 03:45 AM Again, not sure if I can share all the specs here 06-Dec-20 03:46 AM alrighty i'll ping him 06-Dec-20 03:46 AM We do have multiple systems, the one I am referring to is used at SHINE medical to produce medical isotopes 06-Dec-20 03:46 AM impressive 06-Dec-20 03:47 AM Of course, that kind of power can't be put onto solid targets, so that system uses D/T gas target 06-Dec-20 03:47 AM https://phoenixwi.com/neutron-generators/ 06-Dec-20 03:49 AM guess which one's the scintillator, lol 06-Dec-20 03:49 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-BD8A9.png 06-Dec-20 03:49 AM What's the other one then? 06-Dec-20 03:50 AM just epoxy resin 06-Dec-20 03:57 AM still waiting for my chemicals 06-Dec-20 03:57 AM oh and I also found a seller for anthracene, will try that as wavelength shifter 06-Dec-20 03:57 AM as well as some laser dye that is also mentioned in some paper to work as a shifter in scintillators, towards green light 06-Dec-20 10:38 AM I wish the dyes were not so expensive for the higher end of plastic scintillator recipes 06-Dec-20 10:56 AM I recently found the recipe for BC412 06-Dec-20 10:56 AM p-terphenyl as primary component and TPBD as shifter 06-Dec-20 10:56 AM tetraphenyl butadiene 06-Dec-20 10:56 AM the latter is a tad on the expensive side, but shifters are usually in a very low concentration, around 0.2% 06-Dec-20 10:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/img5-D60C4.png 06-Dec-20 10:56 AM also a friend of mine synthesized 2,5-Diphenyl-1,3,4-oxadiazole (DPOD) which is apparently a good shifter for p-terphenyl 06-Dec-20 10:56 AM I think he did a writeup on that 06-Dec-20 10:56 AM hm it's hidden in some forum, it will take a while for me to dig it up 06-Dec-20 11:30 AM Lambdachemie or something else? 06-Dec-20 11:30 AM huh? 06-Dec-20 11:33 AM The forum with the writeup? 06-Dec-20 11:34 AM As I review the the last 12hrs of posts here, here's a reminder to go read the #welcome again. Cracking generally licensed radioactive source open, in fact using them for purposes other than what is specified in the general license, qualifies in the United States. Do not bring that party here. Other countries have substantially similar rules. 06-Dec-20 11:34 AM ah, no 06-Dec-20 11:34 AM apparently the forum is down for legal reasons at the moment :< 06-Dec-20 11:34 AM EU doing EU things with chemical laws 06-Dec-20 11:35 AM REACH and many others had and continue to have a bd result on the hobby 06-Dec-20 11:35 AM Somehow science madness keeps staying up 06-Dec-20 11:37 AM afaik they're working on hosting it outside of the eu 06-Dec-20 11:37 AM it's sad, they already had strict rules about no drugs, explosives etc and still have those issues 06-Dec-20 11:39 AM That's sad 06-Dec-20 11:39 AM And even with those rules, how much thinly veiled drug questions did they get per month? :D 06-Dec-20 11:41 AM the answer is probably "yes" 06-Dec-20 05:00 PM Both this and the video that @GigaSquirrel put up from Carl are themselves demonstrations of general license violations. Do not do this. 06-Dec-20 05:01 PM ^this. We don't do violations of NRC liscenses here and we not be hosting people who do. 06-Dec-20 07:24 PM Just out of curiosity, I assume when Carl did it, it would have been through where he worked. Anyone know more? 06-Dec-20 07:30 PM Wherever he was working, unless he was at a sealed source manufacturing facility, he was busting that general license left right and center. 06-Dec-20 07:38 PM At the time those sources were made, he was working at Linac systems, a manufacturer of RFQ accelerators for BOT fusion among other things. They do not make sealed sources. No one at any properly licensed commercial or academic lab would be taking apart dozens if not hundreds of smoke detectors to make a Am-Be source, so what is shown is done in private 06-Dec-20 07:41 PM Which is good, because if he'd done it at work they'd have fired him promptly. The things he does at home are, well, I hope he owns that place and is never moving. The disclosures are getting awfully long. 06-Dec-20 08:38 PM Ah, makes sense, something in my head hadn’t clicked about that. 06-Dec-20 08:39 PM The nice thing about Carl's stuff is that he documented so much of it well enough that you can vicariously enjoy it without ever having to break any laws yourself. 06-Dec-20 08:39 PM I would not want to be whoever has to deal with his "collection" after he is gone though... No easy or quiet way to legally and safely get rid of a lot of that stuff 06-Dec-20 08:52 PM Which is how my colleagues and I get calls for help from local fire/health departments during estate sales. 06-Dec-20 09:02 PM A lot of those calls seem like cases of overreaction (at least the majority of the ones I have heard about in recent memory) but this would not be one of them. 06-Dec-20 09:10 PM The worst of them seem to be responding to the estates of my deceased colleagues. 06-Dec-20 09:15 PM People who “knew what they were doing?” 06-Dec-20 09:17 PM Collectors, one and all. It's nice to have examples to share with others but they do add up over the decades. I had some words on this topic. http://www.funraniumlabs.com/2020/10/choose-your-own-radiation-adventure-collections-of-the-dead/ 06-Dec-20 09:19 PM Oh I remember that one 06-Dec-20 09:19 PM You’d know better than me but when I read the bit about home electrical stuff, my first expectation just jumped to ham radio amplifier 06-Dec-20 09:19 PM I guess that would be the hoped for reason 06-Dec-20 09:22 PM Mmmmm, ham. Sorry, I should go have a late dinner. 06-Dec-20 09:32 PM Is any capture/transmutation reaction a kind of 'source manufacturing'? or is the problem that a source (e.g. Carl's nuclespot(s)) licensed for de-staticking records or whatever is being used for a nuclear experiment? 06-Dec-20 09:32 PM not to split hairs, but i'm now curious with how much experiment/filtration/whatever I can put around an exempt check source without getting on someone's bad side 06-Dec-20 09:33 PM It's that the source is not being used for its original manufacturer intended purposes, and in some cases being removed from their original enclosures that violates the general license 06-Dec-20 09:33 PM yea, i definitely understand the incredible badness of mauling apart a licensed assembly 06-Dec-20 09:34 PM lol, same, spent way too long tonight doing serial dilution of phosphorus solutions to irradiate tomorrow... 06-Dec-20 09:36 PM As far as an exempt check source, as long as you don't open the source up, remove the source material by concentration/purification, it should be fine for just about any purpose 06-Dec-20 09:36 PM Other than stacking a bunch of them together to increase effective activity if I recall correctly 06-Dec-20 09:38 PM Huh I didn't know about that part of the regulation 06-Dec-20 09:38 PM How much is "a bunch"? 06-Dec-20 09:40 PM 10CFR30.18e over the exempt activity limit 06-Dec-20 09:43 PM Ah, but 30.71 Schedule B applies to the total amount of exempt source material that you can own too. So no matter how those sources are put together, stacking them or not, it would be considered a violation 06-Dec-20 09:43 PM Stacking a few check sources together should be totally fine though, as long as you don't own so many check sources that it exceeds 30.71 Schedule B 06-Dec-20 09:46 PM Oh wait, right, why’s that in there then 06-Dec-20 09:47 PM It basically says you can't own more aggregate source materials than what's shown in 30.71 Schedule B. It doesn't specify any restrictions as to the geometrical arrangement of the sources 06-Dec-20 09:48 PM Ah, right, now I see what you meant 06-Dec-20 09:48 PM Sorry, see notes on late and spent too long in lab today 06-Dec-20 09:49 PM By aggregate source material, it means from multiple source nuclides too, so that's another reason this is in there 06-Dec-20 09:52 PM ok 06-Dec-20 09:52 PM though weirdly, I don't actually see anything that says a single exempt source couldn't be removed from it's enclosure provided it's not sold. I know I'd personally err on the safe side at least 06-Dec-20 11:05 PM It's not just cracking the assembly. It's using a generally licensed source for an application other than that which it is licensed for that violates the license. As an object example, Carl is using a generally licensed Po-210 anti-static eliminator, still in it's original holder ready for mounting, but has now combined it with a piece of beryllium to make it act as a PoBe neutron source. This constitutes a violation of the general license. 06-Dec-20 11:30 PM I got to disabuse a professor of the notion that it was fine to crack open a variety of general licensed sources on the grounds that the quantities of material contained within were exempt under schedule B. I first got to point out the there was no line for Am-241 as the NRC didn't really want anyone playing with transuranics, but that technically it fell under the other alpha emitters at 100nCi and his 5µCi smoke detector source most definitely was not under this limit, much less the several dozen of them in his box. The only reason he wasn't in trouble for cracking open the Po-210 static eliminator was that Prof. Brayne Geneous had tried to get at one that was roughly 20 years old. The starting activity had been ~500µCi, which would have far exceeded the 100nCi limit and the campus' broadscope license inventory limit for Po-210 when it was brand new. He was very cranky we took his toys away and then stripped his office to decon it. Idiot had managed to damage one of the smoke detector sources. 07-Dec-20 10:41 AM I got pins for my backpack 07-Dec-20 10:41 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-46B6F.png 07-Dec-20 10:41 AM and I hace come to the decision that need more pins 07-Dec-20 10:56 AM Yes, you do. EVIDENCE 07-Dec-20 10:56 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/image0-E94D5.jpg 07-Dec-20 10:58 AM what is bottom row second from left 07-Dec-20 11:00 AM SWOLETORO by my friend Maki Naro 07-Dec-20 11:00 AM nice 07-Dec-20 11:00 AM not sure what I should get 'tho 07-Dec-20 11:00 AM there are no decent s.t.a.l.k.e.r pins 07-Dec-20 11:12 AM Yeah :/ 07-Dec-20 11:14 AM if only fallout was as good as stalker, evidently there are enough pins for it 07-Dec-20 12:07 PM STALKER did not lean into the lulz and branding hard enough to exploit for merch, sadly. Maybe there's a nice pin of a bolt somewhere. 07-Dec-20 12:09 PM I could just weld a pin to a bolt 07-Dec-20 12:14 PM I think it depends exactly what the source is. What nuclide, and whether it’s a Schedule B exempt source or a hotter source under a general licence (eg. 210Po antistatic industrial thingy.) If it’s like one of those 5uCi 137Cs disc sources or something like that, the quantity is schedule B exempt and the intended use is broad - education, teaching, detector calibration, demonstration of shielding and radiation interaction with matter. As long as you’re not physically messing with the integrity or protection of the sealed source I think it’s ok. But I am not your lawyer. And, any attempt to make a neutron source from a source not specifically licensed as a neutron source is a Bad Thing I think. You can get little 210Po exempt sources intended for educational use at 0.1 uCi, and putting it next to a bit of Be might be okay. But I don’t think anything else in a greater quantity is acceptable, as it would not be an exempt quantity, it would be a general license, which doesn’t allow it. I don’t think there are any alpha emitters in any amounts in Schedule B, with the exception of 0.1 uCi 210Po. 07-Dec-20 12:26 PM They're in the catch all of "other alpha emitters" at the very bottom. In general, no regulatory agency of any IAEA signatory nation really wants people messing with them. 07-Dec-20 12:45 PM The catch-all (“Any byproduct material not listed above other than alpha emitting byproduct materials”) is listed at the bottom (0.1uCi) which I think implies no other alpha emitters are allowed under schedule B in any quantity? 07-Dec-20 09:12 PM well this was cool, (if only it had worked...) 07-Dec-20 09:12 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-C74A3.png 07-Dec-20 09:32 PM what is it? 07-Dec-20 09:37 PM mostly just neutron activated air 07-Dec-20 09:37 PM and it was supposed to be phosphorus being measured by a (n,a) reaction but somehow there's ALL the aluminum contamination 07-Dec-20 09:39 PM actually spicy air 07-Dec-20 09:43 PM 31P (n, a) 28Al makes sense 07-Dec-20 09:43 PM Is the cross section big enough? 07-Dec-20 09:45 PM Yes, except for the fact that aluminum is really nice at somehow contaminating everything and masking it 07-Dec-20 09:45 PM This was part of a standard curve 08-Dec-20 03:46 PM I was wondering about that. I believe there’s measurable Pu in trinitite. It’s certainly under 100 nCi in any reasonable quantity of trinitite, but it’s also definitely >0. 08-Dec-20 03:54 PM There certainly is 08-Dec-20 03:54 PM I was wondering if there is a (very small) exempt limit for owning transuranic alpha emitters, e.g. 100 nCi, or if it is actually zero. 08-Dec-20 06:47 PM I looked over all the parts of 10CFR i thought might fit, found absolutely nothing. I'm inclined to believe it just represents such a wildly small amount it's not worth the regulatory bother 08-Dec-20 07:52 PM I suppose technically trinitite would be regulated as SNM then? 08-Dec-20 07:52 PM I don’t know if there is any NRC exemption category that applies to trinitite 08-Dec-20 08:45 PM Only in the sense of what is on the market is out there. Cat’s out of the bag on that and there isn’t enough you can assemble to be an issue. It is, oddly enough, considered to be kinda TENORM. 08-Dec-20 08:45 PM Also, pity a poor German lad whose wishes came true. https://twitter.com/rsudowe/status/1336528540821491713?s=21 09-Dec-20 11:10 AM https://www.orau.org/ptp/collection/Miscellaneous/ableuranotype.htm 09-Dec-20 11:10 AM well that's pretty damn cool 09-Dec-20 11:12 AM It would be interesting to do a survey around the Marshall Islands 09-Dec-20 11:12 AM Sample some lagoon water, it is still accessible to tourists on most of the islands, and people regularly dive there 09-Dec-20 11:13 AM https://nucleus.iaea.org/sites/ReferenceMaterials/Pages/IAEA-410.aspx 09-Dec-20 11:15 AM Surprisingly quite affordable! It would be nice to see if there is any appreciable background in the settled atolls though, and see if much of the fallout is from Castle Bravo alone 09-Dec-20 11:17 AM I ordered their thorium ore a few weeks ago, and two a three days ago they contacted me about needing more info, haven't heard anything since then 09-Dec-20 11:21 AM Might be tough to date the fallout from those tests since it all happened within a relatively short time quite a long time ago 09-Dec-20 11:21 AM 1.6 Hiroshimas a day of average yield, quite terrifying when it's all out in the open like this 09-Dec-20 11:43 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-11AEC.png 09-Dec-20 12:16 PM I demand the full DOI for this paper 09-Dec-20 12:21 PM it's a lab report from a friend of mine 09-Dec-20 12:53 PM That uranotype page is really neat, too bad the page they link to has long since died...but the internet archive comes to the rescue: https://web.archive.org/web/20060718103530/http://home.nyc.rr.com/waitaminute/Process.html 09-Dec-20 12:53 PM "Uranium Gold Print A hybrid process using a mixed uranium and gold sensitizer, which then developed as a uranotype, giving split brown-blue tones in uranyl ferrocyanide and colloidal gold." 09-Dec-20 12:53 PM Oh man I wish there were photos of that sort of print 09-Dec-20 12:55 PM Oh wait you meant uranium gold printing, yeah that would be cool 09-Dec-20 12:56 PM Yeah it really describes, apparently, a way to make uranium gold photographic prints vs just uranotypes or chrystotypes 09-Dec-20 08:41 PM well, it's less than amazing but that's the first test with an old crystal that's wayyyy too large for being fed into a cheap sound card 09-Dec-20 08:41 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A8571.png 09-Dec-20 11:04 PM yay! 10-Dec-20 12:04 AM https://www.ebay.de/itm/133532965195 This might be @funranium level spicy 10-Dec-20 12:28 AM Do you have a moment to talk about our lord and saviour red pitaya? 10-Dec-20 12:28 AM :P 10-Dec-20 12:34 AM believe me, I'm well aware, and very tempted to get myself one 10-Dec-20 12:42 AM Heh, just rewatched a berkeley nucleonics stream about compton suppressors and suddenly @Mason_Yu is on tv 10-Dec-20 01:27 AM https://www.ebay.de/itm/133600965768 Not sure what it is, but it looks like one hell of a teardown 10-Dec-20 03:41 AM Gotta love the fact they are encouraging the move to digital pulse processing! That made so many NIM bins available on the second-hand market, just grabbed 10 assorted bins for $39.99 10-Dec-20 03:41 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-4FF34.png 10-Dec-20 03:44 AM ohh wow 10-Dec-20 03:47 AM And got an amplifier that's suitable for reset preamps, time for the next tank of LN2 soon 10-Dec-20 03:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/s-l1600-D73D3.png 10-Dec-20 03:47 AM I'm curious about this automatic fine-tuning circuit 10-Dec-20 03:47 AM That ten turn pot for fine gain adjustment is also very appreciated, it should allow me to take full advantage of the full scale voltage range in any ADC 10-Dec-20 03:47 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/model_2025_Super_Spec1-EE9FC.pdf 10-Dec-20 05:18 AM Did you ever get the ICB amp to work? 10-Dec-20 05:18 AM That also has the equivalent auto pole/zero. 10-Dec-20 09:19 AM "Uranium glass" eh? Pretty sure that's radium, seller. 10-Dec-20 09:31 AM Yep 10-Dec-20 09:31 AM a whole lot of it 10-Dec-20 09:42 AM @funranium did I miss the answer to your choose your own adventure about where to yeet an RTG if the range safety officer decides the rocket is not going to space today? 10-Dec-20 10:01 AM The answer is: ocean. Always aim for the big briny deep to conceal sins but, maybe, stop doing drag line fishing period. Not just because you might disturb something you've dropped down there. It also came with the good news we've never lost one on launch. ...re-entry is another matter. 10-Dec-20 10:06 AM Speaking of radium...how did people wear watches with radium lume dials? Yikes. This one I have gives off like 2500cpm through the acrylic crystal on a soviet pancake tube (SBT10A) w/ the aluminum cover on the tube... 10-Dec-20 10:06 AM well to be fair the watches were pretty solid and it's "only" dose to the hand, which can withstand a lot more 10-Dec-20 10:06 AM but then again there's a very good reason we don't do that anymore 10-Dec-20 10:07 AM Yeah I was just surprised because it has a fairly small amount of the radium lume unlike a lot of military watches from the same period 10-Dec-20 10:07 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/130027185_401841604353281_2179530589722116-093D5.jpg 10-Dec-20 10:07 AM The numbers, tiny bit on the hands, and a dot at each hour marker 10-Dec-20 10:08 AM yep 10-Dec-20 10:08 AM s p i c y 10-Dec-20 10:08 AM Now I wonder how bad some of the military watches are D: 10-Dec-20 10:08 AM yes. 10-Dec-20 10:19 AM hmm, I'm playing aroudn with my CaF2:Eu scintillator, and I'm not exactly sure what's going on here 10-Dec-20 10:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-33624.png 10-Dec-20 10:19 AM this is the spectrum I get from radium 10-Dec-20 10:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-FB818.png 10-Dec-20 10:19 AM I think the peaks are the x-ray clusters around 13 keV, the two gammas at ~47 and ~53 keV, and then Ra / lead XRF around 80 keV 10-Dec-20 10:19 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-194D2.png 10-Dec-20 10:19 AM that would make sense looking at the reference spectrum interspec gives 10-Dec-20 10:19 AM and with the according asymmetry of the peaks, but I'm really not sure about all this low energy stuff 10-Dec-20 10:19 AM the crystal is ~2 mm thick, so the detection efficiency at ~80 keV should be ~1/3 of that at 50 keV, so hm 10-Dec-20 10:33 AM ohh 10-Dec-20 10:33 AM my 3 mm lucite as beta blocker seriously attenuates the ~13 keV cluster 10-Dec-20 10:33 AM amazing 10-Dec-20 10:33 AM should stop about 40% of it 10-Dec-20 11:33 AM well hm 10-Dec-20 11:33 AM no 10-Dec-20 11:33 AM it has to be something intrinsic 10-Dec-20 11:33 AM I am confusion 10-Dec-20 11:33 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-BA5EF.png 10-Dec-20 11:33 AM this is what I get from Cs137, with way lower activity 10-Dec-20 11:00 PM Geiger counter procurement time 10-Dec-20 11:00 PM I hope it's still there 10-Dec-20 11:00 PM Unfortunately no reservations, first come first serve basis 10-Dec-20 11:00 PM Turns out that a friend of mine has some Am-241, could use that as a sort of check source 11-Dec-20 01:00 AM Ohhhh noes 11-Dec-20 01:00 AM Sold out 11-Dec-20 01:00 AM Dammit. 11-Dec-20 01:02 AM f 12-Dec-20 03:23 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201212_115049-892CD.jpg 12-Dec-20 03:23 AM woo! 12-Dec-20 03:23 AM sadly it's impure as all hell 12-Dec-20 03:23 AM but a resublimation should fix that 12-Dec-20 03:23 AM and I am still waiting for the xylene I ordered two weeks ago 12-Dec-20 07:07 AM Yeah, sublimation should take care of that hopefully 12-Dec-20 07:09 AM like.... it looks bad 12-Dec-20 07:09 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-D94CF.png 12-Dec-20 07:09 AM Yikes 12-Dec-20 09:37 AM What purity is that? 12-Dec-20 09:37 AM I would be talking too the supplier if it was anything over 99% 12-Dec-20 09:52 AM there was no purity specified 12-Dec-20 10:00 AM @Mason_Yu what was the activity of that 14C light source, 4mCi? 12-Dec-20 10:24 AM Ahh...I have gotten burned buying stuff w/o purity specified before 12-Dec-20 10:24 AM Sometimes it feels like they go around with a dustpan to clean up and fill out the last bit of a bottle haha 12-Dec-20 11:04 AM Yep :D 12-Dec-20 01:26 PM @Addison-110m It was 9 mCi, surprisingly very low activity although the puck is not that big 12-Dec-20 01:26 PM My laptop running Linux has been stuck at my desk at work lately, so I haven't been able to test everything after I got the cables and installed EPICS and the related modules one by one on that laptop 12-Dec-20 01:43 PM @GigaSquirrel most people probably just use it as a UV tracer or wood preservative or other non critical use so the seller probably does not ever get any complaints especially if purity is not given. Unfortunately not everybody is building scintilators at home. Pity actually. The world might be a better place if they did! 12-Dec-20 01:46 PM Ah, thanks 12-Dec-20 01:47 PM let's hope it works 12-Dec-20 02:06 PM That's from the XP-100 probe right? If it's a smart probe, it should have internal HV power supplies and signal processing, and that might be some artifact from that? 12-Dec-20 02:06 PM it no longer is a smart probe 12-Dec-20 02:06 PM Doesn't look like the probe would be designed for spectroscopy, since CaF2:Eu is not good for that. Did you use your own PMT then? 12-Dec-20 02:07 PM nah I just took out the electronics 13-Dec-20 02:34 PM The micro analyst has an internally mounted NaI scintillator, so that's at least one difference 13-Dec-20 02:36 PM But I think the circuit they described will work for the surveyor, just have to swap out R2 and R4 for a trimpot of appropriate values, and that's it 13-Dec-20 02:36 PM hm, that sounds really interesting to try 13-Dec-20 02:37 PM I've been trying to find where I put my trim pots, will try it tonight if I can find them 13-Dec-20 02:39 PM one of my meters has a similar thing where I'm debating replacing R10 with a resistor-trimpot combination so I can adjust sensitivity a bit 13-Dec-20 02:39 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-22645.png 13-Dec-20 03:34 PM There’s a Geiger counters group I’m on that have posted hacks with Bicron counters. 13-Dec-20 03:34 PM It is possible on some boards to add more features. 13-Dec-20 03:34 PM But there are two main types of boards, and only so much can be done. 13-Dec-20 03:34 PM I think it’s also possible to add a back to turn off the overload / saturation detection which is necessary if you use a PMT based scint probe. 13-Dec-20 03:36 PM Both of these meters have a switch inside to turn off saturation detection 13-Dec-20 03:36 PM The only other feature I think would be useful is a positive pulse output for external MCAs, whether that be Red Pitaya or sound cards 13-Dec-20 03:36 PM But other than that and setting your own discriminator levels, I don't think there's much more you can ask for in a rate meter 13-Dec-20 04:04 PM i think that's a built in switch on a lot of them 13-Dec-20 04:40 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/PXL_20201212_183151055-0C4BD.jpg 13-Dec-20 04:40 PM These switches and pots are very nicely labeled too 13-Dec-20 06:45 PM I got a kit with a surplus board for one of those, a meter, and the multi-switch assembly. 13-Dec-20 10:02 PM https://www.ebay.com/itm/Vintage-Display-IGG1-64x64-M-1-64x64M-Dot-matrix-Nixie-Plasma-Panel-OTK-NEW/274607973846 13-Dec-20 10:02 PM gamma camera anyone? 13-Dec-20 11:04 PM Hm? 14-Dec-20 12:33 AM bias every neon element just below strike voltage 14-Dec-20 12:39 AM that's not how it works 14-Dec-20 12:40 AM The discharges wouldn’t quench though would they? 14-Dec-20 12:43 AM and they would not start reliably, you need gain 14-Dec-20 03:55 AM https://twitter.com/GrantWTrent/status/1338452236473667587 14-Dec-20 02:28 PM oh @GigaSquirrel, with the liquid scintillator, if you end up building something you can get spectra out of, looks like most of the spectra processing shouldn't require any LSC specific software 14-Dec-20 02:28 PM At least if you're willing to do a lot of math 14-Dec-20 02:29 PM I am working on plastic scintillators, not liquid 14-Dec-20 02:29 PM for beta / gamma detection 14-Dec-20 02:30 PM oh 14-Dec-20 02:30 PM I got scrambled with the xylene mention 14-Dec-20 02:30 PM but they're similar in chemistry from what I read 14-Dec-20 02:30 PM yeah, i'd imagine 14-Dec-20 02:30 PM the xylene is there to mix the active ingredients with epoxy 14-Dec-20 02:31 PM Ah 14-Dec-20 02:31 PM and by "there" I mean still at the goddamn seller 14-Dec-20 02:31 PM I ordered it two weeks ago! 14-Dec-20 02:32 PM yikes, I guess I'm lucky, I probably could still get it at a hardware store and redistil it 14-Dec-20 02:32 PM I don't have a distillery 14-Dec-20 02:32 PM yeah, that'd be a hiccup 14-Dec-20 02:33 PM might be able to bodge one together, but with the xylene I ordered p-terphenyl which is quite important 14-Dec-20 02:33 PM oh right, that was your other scintillator 14-Dec-20 02:33 PM other? 14-Dec-20 02:35 PM wasn't the anthracene for something related? 14-Dec-20 02:35 PM ahh 14-Dec-20 02:35 PM yeah, trying that as a wavelength shifter 14-Dec-20 02:35 PM with the terphenyle 14-Dec-20 02:36 PM Ah 14-Dec-20 02:36 PM it will be a terrible shifter but eh 14-Dec-20 02:44 PM it'll be interesting to see 14-Dec-20 02:44 PM or a complete waste of money 14-Dec-20 02:44 PM we'll see 14-Dec-20 02:44 PM I still have to clean the anthracene 14-Dec-20 02:57 PM here's hoping it isnt 15-Dec-20 03:09 AM wow, this image is powerfull 15-Dec-20 03:09 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-F457A.png 15-Dec-20 03:09 AM (inside chernobyl) 15-Dec-20 01:48 PM Can you guess which paint is radioactive and which isn't 15-Dec-20 01:48 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/DSC_8460-9D4E9.JPG 15-Dec-20 02:29 PM hands are dial face isn't? 15-Dec-20 02:31 PM spot on! 15-Dec-20 07:18 PM Can't be too sure, gotta taste it to really know 15-Dec-20 10:42 PM Are you Galen Winsor reincarnate? 16-Dec-20 12:35 AM https://www.youtube.com/watch?v=svuwOKoORzM 16-Dec-20 12:48 AM https://youtu.be/Ec2jY3oQoC0 16-Dec-20 12:48 AM Reminds me of this thing I tried nearly a decade ago 16-Dec-20 12:52 AM the lack of gloves and hands near high voltage are a nice touch 16-Dec-20 12:52 AM good thing one doesn't throw whatever they're holding when they get shocked 16-Dec-20 05:20 AM I just saw Carl’s microphone video. 16-Dec-20 05:20 AM If the second Am-241 source is 80 uCi from an industrial smoke detector, I have to wonder what the first source, which sounded louder, was.... 16-Dec-20 08:50 AM Funny thing is I think that is actually the least "active" part of those smoke detectors isn't it? He seems to have the metal shield over the Am241 strip? Think the more active parts of those are inside the metal cap that makes the ionization chamber and the 80uCi is the total activity with all the strips combined: http://www.diyphysics.com/2013/01/20/80-%C2%B5ci-americium-241-sources-inside-old-pyrotronics-f35a-smoke-detectors/ 16-Dec-20 08:50 AM The first source he is messing with looks like it has threads on the back side (that is getting held) which makes me wonder if that is something Carl put together 16-Dec-20 08:57 AM https://web.archive.org/web/20130521043727/http://www.hss.energy.gov/sesa/analysis/ll/lldb/detail.CFM?Lessons__IdentifierIntern=1995-RL-WHC-0014 16-Dec-20 08:59 AM Do they have an entry in that lessons learnt database that you should not mix organic kitty litter with your radioactive waste? 16-Dec-20 08:59 AM https://wipp.energy.gov/Special/AIB_WIPP%20Rad_Event%20Report_Phase%20II.pdf 16-Dec-20 08:59 AM Such a long report for an issue that boiled down to using the wrong kitty litter 16-Dec-20 08:59 AM And I guess that's major contributing cause for shutdown of the only deep geological repository in the US 16-Dec-20 09:02 AM That's an interesting report about contamination but it really would be interesting to know where exactly the contamination came from: "Another possibility discussed was radiation degradation of the source's integrity either from the americium source itself, or a combination of radiation from the source and the radiation fields where the detectors were located. Many of these detectors were installed in radiological areas in the facility. " 16-Dec-20 09:02 AM There’s a fun thing I learned a while back similar to both of those sound videos, when GM tubes pulse you can also often hear them if you listen just to the tube 16-Dec-20 09:02 AM Sounds like they were unable to rule out environmental contamination as a possible source 16-Dec-20 09:23 AM Asked Carl what that first alpha source was and he does not even know which for some reason makes it all the more concerning... His response: "I am not sure, myself. I just know it is a fairly warm Am-241 source." 16-Dec-20 09:45 AM winces 16-Dec-20 09:45 AM Short answer: yes 16-Dec-20 12:31 PM o hey 16-Dec-20 12:31 PM https://www.mtixtl.com/linbo3sawgradez-cut.aspx 16-Dec-20 12:31 PM you can get z-cut pyroelectric crystals 16-Dec-20 12:31 PM they are pretty cheap too 16-Dec-20 12:31 PM I wonder if it would make a good pyroelectric x-ray source 16-Dec-20 12:34 PM Or neutron source 16-Dec-20 12:34 PM Crystal is a bit too small for that 16-Dec-20 12:34 PM And the yields are admittedly not great with D-D 16-Dec-20 12:37 PM yeah these 1mm crystals may do 30kV max 16-Dec-20 12:37 PM it seems amptek's was 2mm thick by 5x5mm 16-Dec-20 12:37 PM and theirs was 30kv 16-Dec-20 12:37 PM so this 1mm one let's say.... 15kv? 16-Dec-20 12:42 PM It depends a lot on how much space you dedicate to cooling and heating electronics 16-Dec-20 12:44 PM and presumably the dielectric strength of the crystal 17-Dec-20 07:46 PM https://vm.tiktok.com/ZMJg9jSh7/ 17-Dec-20 08:02 PM And I was reminded of this recently: 17-Dec-20 08:02 PM http://blog.nuclearsecrecy.com/2012/08/29/forbidden-spheres/ 17-Dec-20 08:02 PM The story of the classified orange at Los Alamos. 17-Dec-20 08:14 PM that sphere has come up so many times 17-Dec-20 08:14 PM that 17-Dec-20 08:14 PM someone needs to make it an emote 18-Dec-20 05:58 AM i can't find a good emote-able version, if anyone wants to conjure up their favorite rendition i can add the Orb of Hubris 18-Dec-20 06:02 AM The pic above isn’t the demon core. 18-Dec-20 06:14 AM It was taken by Mordechai Vanunu, secretly, in Israel’s Diamona nuclear site. 18-Dec-20 06:14 AM It was leaked to the media, essentially proving that yes, Israel has nukes. 18-Dec-20 06:14 AM I’m not sure if that hole is for injection of tritium, or insertion of a neutron absorbing safing wire. 18-Dec-20 08:14 AM https://twitter.com/GigaBecquerel/status/1339953011179868160 19-Dec-20 05:44 AM hyper hyper 19-Dec-20 05:44 AM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/IMG_20201219_143907-7671D.jpg 19-Dec-20 11:22 AM first tests went... eh 19-Dec-20 11:22 AM I made an error with the soluability of p-terphenyl in xylene and it all crashed out in the epoxy 19-Dec-20 11:22 AM turns out I need an order of magnitude less p-terphenyl 19-Dec-20 11:22 AM a surprise for sure, but a welcome one 19-Dec-20 05:46 PM ICP ion source looks fun 19-Dec-20 05:46 PM @GigaSquirrel where'd you find the glass tube thing? 19-Dec-20 09:49 PM You can probably use a thick glass test tube, put it inside a quick connect fitting of the right size and seal with the viton o-ring 19-Dec-20 09:49 PM That's kinda what I'm planning to do with mine 20-Dec-20 12:38 AM it's a housing for a uvc Aquarium lamp 20-Dec-20 01:15 AM Clever! Which one worked the best? 20-Dec-20 01:17 AM what do you mean? 20-Dec-20 01:18 AM I mean, what lamp holder? Is it quartz? 20-Dec-20 01:18 AM https://www.ebay.de/itm/142992413891 20-Dec-20 01:18 AM and the adapter / Holder to KF is DIY 20-Dec-20 01:37 AM mmm, deuterium tanning bulb 20-Dec-20 01:37 AM there's a decent smell of ozone involved 20-Dec-20 01:37 AM but all the tests so far were just air 20-Dec-20 03:13 PM Hmm I think my proportional counter is dead... 20-Dec-20 03:13 PM https://www.lndinc.com/products/x-ray-proportional-counters/4567/ 20-Dec-20 03:13 PM I gave this 1750 V from one of the bicron surveyors (the highest this particular meter will provide), looked for pulses right after the decoupling capacitor, and saw nothing 20-Dec-20 03:13 PM Surely I would be seeing some gas gain even though I'm slightly below the recommended operating voltage for this 20-Dec-20 03:13 PM Very possible that the xenon in it has just leaked out I guess 20-Dec-20 03:13 PM Also I have no idea why LND put M2.3-0.4 threads all over this thing 20-Dec-20 03:18 PM well you're looking for few pC or maybe fC pulses 20-Dec-20 03:18 PM which are not easily found 20-Dec-20 03:19 PM I guess the next reasonable step is to put the signal through an amplifier, but I doubt I'd see much, since the HV supply from this meter is quite noisy 20-Dec-20 03:19 PM The voltage is a big limiting factor as well for gain, and so I'll have to hook this up to the NIM bin after all 20-Dec-20 03:19 PM With a proper pre-amplifier and everything 20-Dec-20 03:23 PM which is the proper way to test those 20-Dec-20 03:23 PM I know, but tiny gas proportional counter sensitive to super low energy x-rays which is portable would be very neat! 20-Dec-20 03:24 PM it sure would 20-Dec-20 03:24 PM but that's not Impossible 20-Dec-20 03:24 PM Not possible with this meter, that's for sure, so much switching noise on the power supply 20-Dec-20 03:24 PM I also wish there is an old-fashioned radioshack style electronics store near me 20-Dec-20 03:29 PM people are doing their best to kill those 20-Dec-20 03:29 PM The last remaining one near me closed last winter 20-Dec-20 03:29 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/unknown-A4CC6.png 20-Dec-20 03:29 PM A sad sight, unfortunately 20-Dec-20 03:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/PXL_20201220_234410312-E2DDB.jpg 20-Dec-20 03:44 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/PXL_20201220_234418216-C6EB6.jpg 20-Dec-20 03:44 PM These cheap NaI scintillator probes are so sensitive 20-Dec-20 03:44 PM This will be my choice for survey and gamma spec on the go from now on 20-Dec-20 03:53 PM The background count rate on mine is about 5000 cpm 20-Dec-20 03:53 PM And I maxed out the rate meter at 500000 cpm with 1.25 uCi of Cs-137 20-Dec-20 04:59 PM I have that same NaI probe 20-Dec-20 04:59 PM I think i got it from McMaster 20-Dec-20 04:59 PM But i haven't been able to get it working 20-Dec-20 05:00 PM I save a similar but smaller one that’s not been working right recently 20-Dec-20 05:00 PM Do you know what voltage it wants to see? 20-Dec-20 05:02 PM I had luck with around 900V 20-Dec-20 05:02 PM But I’m not sure exactly 20-Dec-20 05:02 PM I need to open mine up and see what the pmt inside is/if the crystal is still ok 20-Dec-20 05:04 PM My probe works well at 850V 20-Dec-20 05:27 PM Welp mine might be hosed then 20-Dec-20 05:27 PM I definitely tried it at ~ 800V 20-Dec-20 05:28 PM Did you get yours from Ukraine? 20-Dec-20 05:28 PM What have you been trying to drive it with? 20-Dec-20 05:28 PM Ludlum 12 20-Dec-20 05:28 PM It has an adjustable voltage 20-Dec-20 05:28 PM Dunno where john got it from originally 20-Dec-20 05:28 PM https://www.ebay.com/itm/BICRON-SAINT-GOBAIN-CRYSTALS-AND-DETECTORS-1-12x1-12m3-1-12-l/164415759573 20-Dec-20 05:28 PM I think there is a much greater chance for these ones to be good 20-Dec-20 05:29 PM Oh damn that’s a nice deal 20-Dec-20 05:29 PM As in the crystals not being a blob of yellow mess 20-Dec-20 05:31 PM Colorado 20-Dec-20 05:31 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201220_173111-10795.jpg 20-Dec-20 05:31 PM Press fit so not particularly serviceable 20-Dec-20 05:32 PM They are not exactly the same, you should take a radiograph of it 20-Dec-20 05:32 PM Just to see if your crystal is detached from the PMT or anything that might be wrong inside 20-Dec-20 05:32 PM Not a bad idea i should wire up my new xray head for the job 20-Dec-20 05:33 PM I already did 20-Dec-20 05:33 PM But don't have enough shielding to go above 30 kV yet 20-Dec-20 05:34 PM Great now I have a project to do tonight 20-Dec-20 05:36 PM I need to put together a water free glove box or get access to one in the chem department to look inside mine 20-Dec-20 11:26 PM success 20-Dec-20 11:26 PM although I don't have my dexis handy so I have nothing to show 21-Dec-20 07:39 AM shot in the dark, but does anyone here have a manual for the Canberra 8224 AMX? I'm not sure how to go about wiring it up to my ADC, and I'm also not sure if it's useful for what I want to try and use it for (PHA with multiple detectors for coincidence counting) 21-Dec-20 08:13 AM Really cool video of how the RBMK refueling machine works: https://youtu.be/NPWMZ8wbqkI 21-Dec-20 11:33 AM I might be able to at least get you the full catalog page for it in a couple weeks 21-Dec-20 11:33 AM If you don’t have much information on it at all 21-Dec-20 12:57 PM Vacuum%20Hackers%20-%20Text%20Channels%20-%20radiation%20%5B597334400618725385%5D.html_Files/20201221_125508-96B17.jpg 21-Dec-20 12:57 PM Anyone happen to have the spec sheet for this tube? 21-Dec-20 12:57 PM I only found the voltages but not the pins 21-Dec-20 01:44 PM @Addison-110m i certainly wouldn't say no, if you remember/get the chance! any first party info could be potentially useful, esp. if it's a particularly content-ful catalog listing 21-Dec-20 01:45 PM There were specifications listed at least if I remember correctly 21-Dec-20 01:45 PM https://discord.com/channels/513115950501855256/597334400618725385/780490804229308426 21-Dec-20 01:46 PM i think i may end up shooting them a very polite, very carefully worded email asking very nicely for like six or seven manuals all at once for all their gear i've accumulated 21-Dec-20 01:46 PM @qualia Are you using Mark Rivers' drivers? 21-Dec-20 01:47 PM mmmmaybe? i'm running EPICS + the mca-7.8 module 21-Dec-20 01:48 PM Ah that is Mark Rivers' drivers 21-Dec-20 01:48 PM Does it support the AMX module though? 21-Dec-20 01:50 PM good question, no idea 21-Dec-20 01:51 PM I doubt the catalog would have documentation on the communication protocol with it 21-Dec-20 01:51 PM oh, mirion bought canberra (?), that ime bodes poorly for wringing historical information out've companies :/.. probably still gonna try anyways 21-Dec-20 01:51 PM yeah, like, it seems to have an ICB connector on the back 21-Dec-20 01:51 PM You just reminded me to go back to the office before Christmas to grab my laptop so I can talk with my ICB modules 21-Dec-20 01:52 PM as well as another port for .. something else? maybe daisy-chaining another ICB thing to it 21-Dec-20 01:52 PM I guess you can talk to these modules if you install EPICS in WSL though right? 21-Dec-20 01:52 PM i have no idea, i use windows to play video games and approximately nothing else 21-Dec-20 01:53 PM Ha... If not for VSCode's WSL integration I would have put Arch or Ubuntu on this laptop too 21-Dec-20 01:53 PM the mca module does have provisions for talking to ICB devices so maybe adding 8224 AMX bank switching support is in the realm of feasible 21-Dec-20 01:53 PM all that said, if there's another option for driving this hardware, be it under windows or elsewhere, i can maybe make that happen as needed (even if just to aid in reverse engineering) 21-Dec-20 01:53 PM as long as it's not a 'sure that'll be $3000 for a software license' kinda deal 21-Dec-20 01:58 PM Oh Carl made a LabView/Matlab driver for it irrc 21-Dec-20 01:58 PM But only for talking to the ADC and it was based on the EPICS driver to get the communication protocol 21-Dec-20 03:13 PM Mark Rivers is the EPICS person behind mca and the Canberra support. 21-Dec-20 03:13 PM I know him. I’ve been in his lab a number of times after meeting him at EPICS meetings. 21-Dec-20 03:13 PM ICB is daisy chained via a ribbon cable. There should just be a single ICB port per module. 21-Dec-20 03:13 PM Adding new ICB devices to EPICS is possible, and I would think Mark might accept a pull request if you get something working. 21-Dec-20 03:13 PM The base ICB communication support is there. The issue is finding what addresses correspond to what variables, then binding them to EPICS PVs. 21-Dec-20 03:13 PM I don’t know if Canberra makes that info public. 21-Dec-20 03:13 PM I think they slipped up, which is how Mark got enough info to write the drivers. 21-Dec-20 03:13 PM It looks like the only ICB devices supported are: 21-Dec-20 03:13 PM 0 = ADC (9635) 1 = Amplifier (9615) 2 = High voltage power supply (HVPS) (9641, 9645) 3 = Three-channel analyzer (TCA) (2016) 4 = Digital signal processor (DSP) (9660) 21-Dec-20 03:13 PM I imagine it would be possible if one had access to a temporary Genie 2000 license to put a logic analyzer on the ICB bus and reverse engineer a module. 21-Dec-20 03:22 PM Extending this to LabView and other perhaps more commonly used control software outside of the accelerator community would be nice too 21-Dec-20 03:23 PM There is an EPICS to LabView bridge. 21-Dec-20 03:23 PM Also it looks like the 9633 ADC is supported as well.