Anyone know of an everyday product that would have a  scintillator in it? - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 13, 2019, 08:51:06 pm
content: For science! No, really. This is kind of a long shot but figured I'd ask maybe there's something I'm not thinking of.Helping a high school student with a project and she had a 5x5 bc408 scintillator in it but it cracked. Not exactly something you can easily get locally and Ebay, Amazon etc would take too long.It basically glows under cosmic rays as this project will have photocells that will measure the cosmic rays. Is there like, a type of paint or chemical or something that would essentially act the same way that would be in an every day product? Yeah total long shot here.Technically the cracked one should still work, but supposedly it's not. She's suppose to call me at some point so I might have more details. My sister is a teacher so she asked me about it.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 14, 2019, 09:34:31 am
content: There is a slight chance that one could use some liquids - there are also liquid scintillators. However they tend to need to be quite clean - so likely tricky to get them somewhere else than a special chemical supply. Also sending out liquids is always tricky.Best bet would likely be the cracked one. It should normally work, though with reduced accuracy in energy resolution and less effective. The problem should be mainly on the optical side - less light getting the detector. Usually the detector needs to be very sensitive, like a PMT.So maybe check if the optical detector actually still works - I would be more afraid of the PMT breaking.

author: Rerouter
author_rank: Super Contributor
timestamp: September 14, 2019, 09:50:02 am
content: You may be able to find a more local source of something like this, as they are made in canada.https://youtu.be/TJcMgoJ4DOE?t=49

author: Kleinstein
author_rank: Super Contributor
timestamp: September 14, 2019, 03:25:33 pm
content: Usually scintillators are use with slightly lower PMT gain than for photon counting. On the other hand one tries to get as much light to the PMT as possible, so have a direct coupling, possible even with some "grease" in direct contract to avoid surface reflection. A high energy particle would cause a short (e.g. a few 10-100 ns) light pulse of maybe some 1000 photons. The information is in the number of peaks and the size of the peaks.There could actually be a chance to get a liquid scintillator work, if one has a suitable PMT. There may be other materials that work, but these tend to be weaker than the BC408. One may gain a little from more size, but the conversion tends to be less effective in a make shift material. So a lot depends on the detector.

author: LaserSteve
author_rank: Super Contributor
timestamp: September 14, 2019, 05:03:41 pm
content: There is seller on ebay who gets surplus ones. Search for Lyso as an item.Steve

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 14, 2019, 10:47:06 pm
content: This launches Monday, so online won't work. But turns out the problem is elsewhere so think they're ok now. I'm suppose to get a call tonight so I'll have more details. It might be an issue with the detector itself. I kinda suspected too as just a crack should not really affect it much, but it depends how it's setup. Maybe the sensor happens to be where the crack is or something.One thing I do wonder is what type of photocell(s) are being used as they need to have a very fast reaction time as from what I was reading on scintillators they don't have much persistence at all, like no more than a few ns.

author: james_s
author_rank: Super Contributor
timestamp: September 14, 2019, 11:08:41 pm
content: They don't use photocells, as someone else mentioned above they use a PMT, photomultiplier tube. These are orders of magnitude more sensitive than solid state sensors.

author: radioactive
author_rank: Regular Contributor
timestamp: September 14, 2019, 11:39:39 pm
content: Glad to hear they got it solved.I really don't know what I'm doing relative to the subject, but I did want to play around with a photon multiplier tube this past year while I took some time off from work. I bought a chunk of BC408 material and a PMT from ebay and made a little board to power it all. I'm pretty sure I measured some muon particles with the the thing. I wrapped the whole assembly in tin foil, and got the following traces on the o-scope. Fun stuff. I didn't get to play with this sort of thing in high school, but it is super cool to hear that this is a thing for HS kids now days.Some images attached.

author: daqq
author_rank: Super Contributor
timestamp: September 15, 2019, 08:31:35 am
content: Isn't normal water a scintillator? They use it in here:https://en.wikipedia.org/wiki/Kamioka_Observatory

author: voltsandjolts
author_rank: Unknown
timestamp: September 15, 2019, 08:50:48 am
content: I have been meaning to try utilising my scope as a pulse height analyser. Canberra may be long gone but PHAs can still be useful, particularly in particle detectors of course. Using segmented memory you could capture, say, a hundred pulses, transfer to PC for pulse height mesurement and plot (edit: histogram), repeat continuously. There would be quite some dead time during the data transfer out of the scope but that just means taking a little longer to gather a useful spectrum so not a showstopper.Why don't scopes have a Pulse Height Analysis option built in, not hard to do? Maybe higher end scopes do have that?

author: Kleinstein
author_rank: Super Contributor
timestamp: September 15, 2019, 09:44:35 am
content: With a reasonable size scintillator the count rate is not that low. I remember some 100 Hz background with a 38 mm NaJ:Ta detector. So the transfer from the scope to PC could really be a bottle-neck. Taking a spectrum still needs quite some time, especially with weak sources. So too much dead time is not a good thing.Using a DSO for peak high measurement should in principle be possible. However it's not such a common application, to have it as a standard function in common DSOs. With increasing more digital functions there is a chance to find it in some more modern ones.In water one sees Cherenkov radiation - it is kind of related, but weaker and is not so sensitive to low energy particles.

author: 2N3055
author_rank: Super Contributor
timestamp: September 15, 2019, 10:16:12 am
content: I don't know much about this kind of application, but if I'm correct, pulse height analysis in this context is basically histogram of amplitude distribution of maximum value of many random pulses in time period. Is that correct ?If it is, than any scope that can make histograms on measurements and support max value can be used. You can set timescale to pulse width, set trigger above minimum pulse width you want to detect, and accumulate values, and bucketize them in histogram.Another way of doing it, would be to use DeepMeasure on Picoscope. You take one long capture, set thresholds, and you get a list of events in a buffer. Export that to Excel and create histogram there. It's really quick..

author: voltsandjolts
author_rank: Unknown
timestamp: September 15, 2019, 10:34:45 am
content: Yes, histogram of pulse peak amplitudes, 'binning' as they say.Any scope can do that you say?!I need to check my MSOX3024.

author: 2N3055
author_rank: Super Contributor
timestamp: September 15, 2019, 11:14:03 am
content: You should check if Rigol MSO5000 can.. Also new Siglent SDS5000X can.Also, Picoscope is interesting. DeepMeasure analyses whole buffer and gives you the list of events with dozen measured parameters. You can export that list and make histogram from that.https://www.picotech.com/library/oscilloscopes/deepmeasureIt also trivially allows you to save captures and analyse them later. They also have great API so you can write your own analysis software.I have MSOX 3104T. It doesn't have histogramming.

author: jimdeane
author_rank: Regular Contributor
timestamp: September 15, 2019, 08:59:28 pm
content: Making a MIT Cosmic Watch detector (or something similar)?If it was needed, the eBay seller was pretty fast...but it's hard to find it locally, and you wouldn't find it in any normal commercial equipment.The light detector attached to these scintillators is a SiPM, essentially an avalanche photodiode array.Source: I have the parts for one of these sitting on my bench for when I have time to work on it (as it has been sitting over a year).

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 16, 2019, 04:01:38 am
content: Yeah it's for a balloon experiment to capture cosmic rays. The student was working with CSA as well and they ended up getting it going as far as I know. They launch tomorrow. I think there's multiple balloons going up, two student ones, and an official CSA one. Or maybe they're putting everything on one I'm not sure.I might try to make it to the launch as I've been meaning to see one in person. They launch some throughout the summer here as we house the stratospheric base for CSA.

author: rs20
author_rank: Super Contributor
timestamp: September 16, 2019, 11:44:23 am
content: Quote from: voltsandjolts on September 15, 2019, 08:50:48 amI haven't read any of the posts in this thread, so I apologise in advance, but how would such a feature differ from Vpp or Vmax?

author: amyk
author_rank: Super Contributor
timestamp: September 16, 2019, 12:08:18 pm
content: My first thought upon seeing the title was "spinthariscope" but then I realised they're not that common anymore.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: September 16, 2019, 01:27:44 pm
content: Quote from: voltsandjolts on September 15, 2019, 08:50:48 amIf the slew rate is too high for the available bandwith, this limits the accuracy of a pulse height/peak measurement drastically, you'd easily be off by some orders of magnitude from reality without knowing because the quantization error became too big. From a practical perspective pulses are meant to be counted, whereas some integrated signal might be better suited to be measured. It sounds intriguing, though, just have a threshold and every pulse in between is binned.In digital signals it might be useful to have it in the form of runt pulse triggering, which means signal either higher, lower or in between, but apart from that scope measurements are mostly suited for repetitive signals.

author: voltsandjolts
author_rank: Unknown
timestamp: September 26, 2019, 04:40:07 pm
content: Quote from: rs20 on September 16, 2019, 11:44:23 amYes, that gets you a single pulse height measurement.Pulse Height Analysers capture hundreds (or thousands) of these and display the results as a histogram.So, a scope has the measurement capability, but I hadn't seen any with histogram option.Apparently SDS5000X does this.

author: 2N3055
author_rank: Super Contributor
timestamp: September 26, 2019, 06:25:19 pm
content: Quote from: voltsandjolts on September 26, 2019, 04:40:07 pmAlso any number of LeCroy scopes, and very possibly new Rigol series 5000/7000/8000.If Rigol 5000 series can do it, it is very inexpensive in comparison to others...

author: Kleinstein
author_rank: Super Contributor
timestamp: September 26, 2019, 07:18:48 pm
content: For the puls hight analysis it would help if the function works real time, thus with little or no dead time, so that not many pulses are lost.For the Pulse high analysis there are 2 ways to do it: either from the maximum value or the total area for the puls. Usually the pulse shape should be the same - so both ways should give proportional results. However the noise could be different.A simple pulse hight analysis is a relatively simple task for a small µC, if a analog peak detector is used. This was one of my first µC projects.A µC with a faster ADC (e.g. 5 MSPS range) could also do this without analog peak detection. So no need to send an Rigol 5000 DSO up with the ballon.

author: 2N3055
author_rank: Super Contributor
timestamp: September 26, 2019, 09:52:05 pm
content: I was replying to voltsandjolts, but yeah for balloon scope is notvery helpful..