On Monday, 18 July 2022 at 15:34:22 UTC+2, Dimiter Popoff wrote:> On 7/18/2022 15:58, a a wrote: > > On Monday, 18 July 2022 at 14:36:34 UTC+2, bill....@ieee.org wrote: > >> On Monday, July 18, 2022 at 9:40:19 PM UTC+10, a a wrote: > >>> On Monday, 18 July 2022 at 12:29:57 UTC+2, bill....@ieee.org wrote: > >>>> On Monday, July 18, 2022 at 8:10:23 PM UTC+10, a a wrote: > >>>>> On Monday, 18 July 2022 at 04:12:12 UTC+2, Mike Monett wrote: > >>>>>> whit3rd <whi...@gmail.com> wrote: > >>>>>>> On Sunday, July 17, 2022 at 1:00:00 PM UTC-7, a a wrote: > >> <snip> > >> > >>> So IEEE is not science body, organization at all. > >> > >> If a a knew what he was talking about, he'd know that the main function of the IEEE is to publish a large collection of high-impact peer-reviewed scientific journals that deal with the science that underlies electronics. That is what science is about, even if a a doesn't have a clue about it. > >> > >> That's why I joined the organisation back around 1980. It's not all that obvious the current activities of the NSW Branch, but that's where the serious effort goes , and where the serious money gets spent. > >> > >> I've got just one short comment in that literature > >> > >> Sloman, A.W. "Comment on 'Computer aided simulation study of photomultiplier tubes'", IEEE Transactions on Electron Devices, ED-38 679-680 (1991). > >> > >> Because I mostly worked in the UK I published more the UK Institute of Physics journals, but there aren't as many of them, and Americans do tend to ignore them. > >> > >> -- > >> Bill Sloman, Sydney--ok, ok, stop your delusiones and day dreaming> >-- IEEE lives on Facebook> >--IEEE is the world's largest technical professional organization dedicated to advancing technological innovation and excellence for the benefit of humanity. --IEEE has offices in China, India, Japan, Singapore, and in the United> > States (California, New Jersey, New York, Washington, D.C.) > > 3,409,150 people like this > > 3,426,770 people follow this > > 2,463 people checked in here > > http://www.ieee.org/ > > +1 800-678-4333-- Send message> > contac...@ieee.org > > Educational Research Center · Engineering Service · Nonprofit Organization > > Privacy Policy > >-- https://www.facebook.com/IEEE.org/> >--just visit and find me a single thread or comment, having anything to do with science or research @Dimiter Popoff’s profile photo @Dimiter Popoff we all love your fake
Low Level Gamma Radiation
Started by ●June 5, 2022
Reply by ●July 18, 20222022-07-18
Reply by ●July 18, 20222022-07-18
On Monday, July 18, 2022 at 10:58:40 PM UTC+10, a a wrote:> On Monday, 18 July 2022 at 14:36:34 UTC+2, bill....@ieee.org wrote: > > On Monday, July 18, 2022 at 9:40:19 PM UTC+10, a a wrote: > > > On Monday, 18 July 2022 at 12:29:57 UTC+2, bill....@ieee.org wrote: > > > > On Monday, July 18, 2022 at 8:10:23 PM UTC+10, a a wrote: > > > > > On Monday, 18 July 2022 at 04:12:12 UTC+2, Mike Monett wrote: > > > > > > whit3rd <whi...@gmail.com> wrote: > > > > > > > On Sunday, July 17, 2022 at 1:00:00 PM UTC-7, a a wrote:<snip>> just visit and find me a single thread or comment, having anything to do with science or researchThe tricky bit would be finding something that you would comprehend as having anything to do with science or research. The comment that I published in the IEEE Transactions on Electron Devices and listed above - which you have snipped - had a quite a lot to do with research - it cited a bunch of references on photomultiplier non-linearity which are relevant to anybody doing serious research that exploits photomultipliers. So you've already had what you asked for, but failed to recognise it, which is exactly how you have always performed ever since you started posting your inanities here. -- Bill sloman, Sydney
Reply by ●July 18, 20222022-07-18
On Monday, 18 July 2022 at 15:41:36 UTC+2, bill....@ieee.org wrote:> On Monday, July 18, 2022 at 10:58:40 PM UTC+10, a a wrote: > > On Monday, 18 July 2022 at 14:36:34 UTC+2, bill....@ieee.org wrote: > > > On Monday, July 18, 2022 at 9:40:19 PM UTC+10, a a wrote: > > > > On Monday, 18 July 2022 at 12:29:57 UTC+2, bill....@ieee.org wrote: > > > > > On Monday, July 18, 2022 at 8:10:23 PM UTC+10, a a wrote: > > > > > > On Monday, 18 July 2022 at 04:12:12 UTC+2, Mike Monett wrote: > > > > > > > whit3rd <whi...@gmail.com> wrote: > > > > > > > > On Sunday, July 17, 2022 at 1:00:00 PM UTC-7, a a wrote: > > <snip> > > just visit and find me a single thread or comment, having anything to do with science or researchyou are stupid dog and your comments exactly represent media standards by IEEE.org since you use official email by IEEE.org listen me once again visit IEEE.org on Facebook and find a single thread, comment having anything to do with science or research https://www.facebook.com/IEEE.org/ I am really not interested in your delusiones and day dreaming
Reply by ●July 18, 20222022-07-18
On 7/18/2022 16:38, a a wrote:> On Monday, 18 July 2022 at 15:34:22 UTC+2, Dimiter Popoff wrote: >> On 7/18/2022 15:58, a a wrote: >>> On Monday, 18 July 2022 at 14:36:34 UTC+2, bill....@ieee.org wrote: >>>> On Monday, July 18, 2022 at 9:40:19 PM UTC+10, a a wrote: >>>>> On Monday, 18 July 2022 at 12:29:57 UTC+2, bill....@ieee.org wrote: >>>>>> On Monday, July 18, 2022 at 8:10:23 PM UTC+10, a a wrote: >>>>>>> On Monday, 18 July 2022 at 04:12:12 UTC+2, Mike Monett wrote: >>>>>>>> whit3rd <whi...@gmail.com> wrote: >>>>>>>>> On Sunday, July 17, 2022 at 1:00:00 PM UTC-7, a a wrote: >>>> <snip> >>>> >>>>> So IEEE is not science body, organization at all. >>>> >>>> If a a knew what he was talking about, he'd know that the main function of the IEEE is to publish a large collection of high-impact peer-reviewed scientific journals that deal with the science that underlies electronics. That is what science is about, even if a a doesn't have a clue about it. >>>> >>>> That's why I joined the organisation back around 1980. It's not all that obvious the current activities of the NSW Branch, but that's where the serious effort goes , and where the serious money gets spent. >>>> >>>> I've got just one short comment in that literature >>>> >>>> Sloman, A.W. "Comment on 'Computer aided simulation study of photomultiplier tubes'", IEEE Transactions on Electron Devices, ED-38 679-680 (1991). >>>> >>>> Because I mostly worked in the UK I published more the UK Institute of Physics journals, but there aren't as many of them, and Americans do tend to ignore them. >>>> >>>> -- >>>> Bill Sloman, Sydney > --ok, ok, stop your delusiones and day dreaming >>> > -- IEEE lives on Facebook >>> > --IEEE is the world's largest technical professional organization dedicated to advancing technological innovation and excellence for the benefit of humanity. > --IEEE has offices in China, India, Japan, Singapore, and in the United >>> States (California, New Jersey, New York, Washington, D.C.) >>> 3,409,150 people like this >>> 3,426,770 people follow this >>> 2,463 people checked in here >>> http://www.ieee.org/ >>> +1 800-678-4333 > -- Send message >>> contac...@ieee.org >>> Educational Research Center · Engineering Service · Nonprofit Organization >>> Privacy Policy >>> > -- https://www.facebook.com/IEEE.org/ >>> > --just visit and find me a single thread or comment, having anything to do with science or research > > @Dimiter Popoff’s profile photo > @Dimiter Popoff > we all love your fakeOh dear. if you are to be a troll at least learn how to post. Finding me/my photos is about the easiest thing to find on the net, at least learn how to do it. Better, instead of trolling invest your time into learning how to do something useful. ====================================================== Dimiter Popoff, TGI http://www.tgi-sci.com ====================================================== http://www.flickr.com/photos/didi_tgi/
Reply by ●July 18, 20222022-07-18
In article <7cce474a-9b26-43bc-8fab-17f97e2bc1b1n@googlegroups.com>, whit3rd <whit3rd@gmail.com> wrote:>On Saturday, July 16, 2022 at 5:38:44 PM UTC-7, Dave Platt wrote: > >> The trickiest part was handling high pulse rates, where one pulse >> starts while the CSA is still recovering from the previous one. >> At some point I may sit down and try writing some DSP code to >> de-convolve the CSA's pulse shaping and turn the signal back >> into narrow impulses. > >The analog-days solution was a delay line amplifier; the long recovery tail >is exponential, so a difference amplification of V(t) - (1+epsilon)V(t-s) >flattens the recovery when (1+epsilon) equals the diminution of the signal >during 's' seconds. The infinite-impulse response or FIR filter is relatively easy >work to do that.Yes, that would be pretty easy to code. Part of the complexity is that the signal chain in my setup is AC-coupled, so the strong positive-going pulse and its exponential-decay recovery are followed by a "sag" down into negative voltages, which then recovers exponentially to zero. If a second pulse hits before this recovery-to-DC is complete, the second pulse's peak will be offset downwards and a naive measure of its height will underestimate its energy. https://www.radagast.org/~dplatt/gamma/pulses.png is a screen-shot from my software's GUI when running in the "look at the signal" mode. What I did in my pulse-detection software was to use a state-machine approach, modeling the pulse in phases - waiting to trigger (blue), rising (green), falling back to the DC baseline (yellow), falling down below DC (orange), and then exponential recovery back upwards to baseline (red). For the latter I have a model for how long it _should_ take to recover back to DC (white), and I hold off further triggers until the estimated recovery time is complete. If the software sees a sudden rise in the signal during any of the post-peak phases, it's interpreted as a second pulse "too soon" and is discarded. Another approach I've been musing about, would be to use correlation - correlate the incoming pulse train with a known-good sample of the system's impulse response. I could capture one good clean pulse (or a few, and then average them) to create a reference... this would accurately model the impulse response of the crystal/PMT/amplifier as actually built. Then, simply run a multiply-and-add correlation to the samples as they come in during a measuring run. This ought to give me a nice, clean, fairly narrow (and close-to-symmetrical) detection pulse for each incoming pulse from the amplifer. This would give my state-machine pulse detector and input with the pulses more cleanly separated. The data rate is low enough and the pulses are short enough that it's probably cheaper to do it through brute-force multiply-and-add, rather than coding it as an FFT/multiply/iFFT.>Some good info here: ><https://www.ortec-online.com/-/media/ametekortec/manuals/4/460-mnl.pdf>Thanks!
Reply by ●July 18, 20222022-07-18
dplatt@coop.radagast.org (Dave Platt) wrote:> In article <XnsAED78EB5BEF31idtokenpost@88.198.57.247>, > Mike Monett <spamme@not.com> wrote: > >>A very lucid explanation. Thanks. > > Quite welcome! > >>I was able to find out what NORM is without having to ask you: "Naturally >>ocurring radioactive materials." I'm so proud of myself:) > >:-) > > The next step in the obsession is to find NORM sources for yourself. > Government and business buildings with granite facades are one > source. > >>How big are your scintillator crystals? > > Ugh... it's been years since I built the probes so I don't recall the > exact size. I think they're both about 1" in diameter and an inch or > two long.Wow! That's big. That's why your detectors are so sensitive. I found some sources for crystals. The smaller ones are not too expensive: 1. https://www.gammaspectacular.com/blue/nai-tl-crystals 2. Saint-Gobain has a lot of papers as well as crystals: https://www.crystals.saint-gobain.com/radiation-detection- scintillators/crystal-scintillators/lanthanum-bromide-labr3 3. Hiler has more info on crystals. Quotes on request: https://www.hilger-crystals.co.uk/guide-to-inorganic-scintillator-crystals/ 4. More info: https://www.mirion.com/learning-center/lab-experiments/gamma-ray-detection- with-scintillators-lab-experiment 5. Berkeley has a wide variety of detectors: https://www.berkeleynucleonics.com/scintillation-crystals-and-detectors Wow! You could get really deep into this topic. And spend 11,780 bazillion dollars. Thanks, Mike -- MRM
Reply by ●July 19, 20222022-07-19
On Monday, June 27, 2022 at 4:42:33 AM UTC-7, Phil Hobbs wrote:> If you're going to use an ionic scintillator in contact with an end-on > PMT (one where the photocathode is deposited directly on the faceplate) > you'll need to keep the cathode near ground to avoid ions migrating > through the glass and corroding the PC. That means running the anode at > high voltage and coupling the pulses out with a cap or transformer or > something.Phil, can you elaborate on this point? If the crystal and PMT are well- insulated from their surroundings, which they are, what mechanism would cause noticeable amounts of ion migration? It's definitely more convenient to run these with negative HV than it would be with positive HV, where you not only have to worry about DC blocking but also ripple. The latter seems to be a big deal, going by the Theremino docs and other sources. -- john, KE5FX
Reply by ●July 19, 20222022-07-19
On Wednesday, July 20, 2022 at 11:04:28 AM UTC+10, John Miles, KE5FX wrote:> On Monday, June 27, 2022 at 4:42:33 AM UTC-7, Phil Hobbs wrote: > > > > If you're going to use an ionic scintillator in contact with an end-on > > PMT (one where the photocathode is deposited directly on the faceplate) > > you'll need to keep the cathode near ground to avoid ions migrating > > through the glass and corroding the PC. That means running the anode at > > high voltage and coupling the pulses out with a cap or transformer or > > something. > > Phil, can you elaborate on this point? If the crystal and PMT are well- > insulated from their surroundings, which they are, what mechanism > would cause noticeable amounts of ion migration? > > It's definitely more convenient to run these with negative HV than it would be > with positive HV, where you not only have to worry about DC blocking but > also ripple. The latter seems to be a big deal, going by the Theremino > docs and other sources.A high voltage across a photomultiplier faceplate will do it. At Cambridge Instruments, the photomultipliers we bought were selected to deliver the gain we needed with less than 1kV across the tube - which is to say across the glass faceplate. A quartz - silicon-dioxide - face-plate might have been expected to be immune, but they needed an expensive graded seal to couple them onto the glass body of the photopmultiplier tube Quite how 1kV got to be selected as the cut-off point was never revealed to me, but it was embedded in our purchasing specification. The tubes themselves were mounted hard up against a glass window in the (grounded metal) specimen chamber, so that they could detect the flashes of light coming of the scintillator in the Everhart-Thornley secondary electron detection system. Regular glass seems to contain enough metal ions for ionic migration to be a problem under kilo-volt potential differences. -- Bill Sloman, Sydney
Reply by ●July 20, 20222022-07-20
On Tuesday, July 19, 2022 at 7:01:46 PM UTC-7, bill....@ieee.org wrote:> A quartz - silicon-dioxide - face-plate might have been expected to be > immune, but they needed an expensive graded seal to couple them > onto the glass body of the photomultiplier tubeI see, so the issue is the potential difference between the photocathode and the exterior metalwork. They seem to have thought of that, as the tube's metal frame is tied to the cathode pin. -- john, KE5FX
Reply by ●July 20, 20222022-07-20
On Wednesday, July 20, 2022 at 2:11:03 PM UTC+10, John Miles, KE5FX wrote:> On Tuesday, July 19, 2022 at 7:01:46 PM UTC-7, bill....@ieee.org wrote: > > A quartz - silicon-dioxide - face-plate might have been expected to be > > immune, but they needed an expensive graded seal to couple them > > onto the glass body of the photomultiplier tube > > I see, so the issue is the potential difference between the photocathode > and the exterior metalwork. They seem to have thought of that, as the > tube's metal frame is tied to the cathode pin.Some of it is. The anode isn't and none of the dynodes are, and every last one of them it is tied to a metal pin coming out of the base. -- Bill Sloman, Sydney
