On Saturday, June 25, 2022 at 11:16:45 AM UTC-7, Mike Monett wrote:> I tried to order one. Does not ship to Canada. Can you order one and mail it > to me? I can pay you via Paypal. Thanks.Maybe. I'll have to surf through the Commerce and ITAR lists to see if there's a reason why the seller doesn't ship to Canada. Shifty folk, Canadians. (It'll be a few days before I have time to deal with it, for various reasons.) -- john, KE5FX
Low Level Gamma Radiation
Started by ●June 5, 2022
Reply by ●June 26, 20222022-06-26
Reply by ●June 26, 20222022-06-26
"John Miles, KE5FX" <jmiles@gmail.com> wrote:> On Saturday, June 25, 2022 at 11:16:45 AM UTC-7, Mike Monett wrote: >> I tried to order one. Does not ship to Canada. Can you order one and >> mail it to me? I can pay you via Paypal. Thanks. > > Maybe. I'll have to surf through the Commerce and ITAR lists to see if > there's a reason why the seller doesn't ship to Canada. Shifty folk, > Canadians. > > (It'll be a few days before I have time to deal with it, for various > reasons.) > > -- john, KE5FXThat's fantastic. Thanks. A lot of US vendors don't want to ship to Canada. But the majority do ship with no problem. Spending time to find out why may give mixed results. I can probably ask the vendor what his reasons are. In the meantime, my main goal is to get a copy of his model before he runs out or gives up. I will send my name and address to your gmail address. Again, thanks. Mike -- MRM
Reply by ●June 27, 20222022-06-27
Mike Monett wrote:> "John Miles, KE5FX" <jmiles@gmail.com> wrote: > >> On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote: >>> My Radiascan Radiacode finally arrived from Russia. After the >>> sanctions, I was surprised to see it made it. >> >> This listing is also very interesting: >> >> https://www.ebay.com/itm/194659036410 >> >> Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each. >> Wonder how they'd compare to the solid-state CsI(Tl) detector assembly >> in the Radiacode unit? >> >> -- john, KE5FX > > I tried to order one. Does not ship to Canada. Can you order one and mail it > to me? I can pay you via Paypal. Thanks.For any serious use, I'd budget for a replacement PMT. They age out after several years, which is probably why these assemblies were replaced. They also wear out on account of photocurrent--the usual rule is that you can get an integrated anode charge of about 1000 C/cm**2 of photocathode area before the gain drops by ~half. 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. Using an air gap between scintillator and tube allows you to keep the anode near ground, which is much more convenient, but costs you about half your light. (The collection efficiency goes like the etendue, which has a factor of n**2 in it.) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●June 27, 20222022-06-27
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:> Mike Monett wrote: >> "John Miles, KE5FX" <jmiles@gmail.com> wrote: >> >>> On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote: >>>> My Radiascan Radiacode finally arrived from Russia. After the >>>> sanctions, I was surprised to see it made it. >>> >>> This listing is also very interesting: >>> >>> https://www.ebay.com/itm/194659036410 >>> >>> Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each. >>> Wonder how they'd compare to the solid-state CsI(Tl) detector assembly >>> in the Radiacode unit? >>> >>> -- john, KE5FX >> >> I tried to order one. Does not ship to Canada. Can you order one and >> mail it to me? I can pay you via Paypal. Thanks. > > For any serious use, I'd budget for a replacement PMT. They age out > after several years, which is probably why these assemblies were > replaced. They also wear out on account of photocurrent--the usual rule > is that you can get an integrated anode charge of about 1000 C/cm**2 of > photocathode area before the gain drops by ~half. > > 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. > > Using an air gap between scintillator and tube allows you to keep the > anode near ground, which is much more convenient, but costs you about > half your light. (The collection efficiency goes like the etendue, > which has a factor of n**2 in it.) > > Cheers > > Phil HobbsGood information. Thanks. I'm not planning on heavy use. The idea is to compare the scintillator againt the Radiacode, and try to measure any Radon gas in the basement. Then it will probably go into storage. -- MRM
Reply by ●June 28, 20222022-06-28
On 28/06/2022 08:01, Mike Monett wrote:> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> Mike Monett wrote: >>> "John Miles, KE5FX" <jmiles@gmail.com> wrote: >>> >>>> On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote: >>>>> My Radiascan Radiacode finally arrived from Russia. After the >>>>> sanctions, I was surprised to see it made it. >>>> >>>> This listing is also very interesting: >>>> >>>> https://www.ebay.com/itm/194659036410 >>>> >>>> Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each. >>>> Wonder how they'd compare to the solid-state CsI(Tl) detector assembly >>>> in the Radiacode unit? >>>> >>>> -- john, KE5FX >>> >>> I tried to order one. Does not ship to Canada. Can you order one and >>> mail it to me? I can pay you via Paypal. Thanks. >> >> For any serious use, I'd budget for a replacement PMT. They age out >> after several years, which is probably why these assemblies were >> replaced. They also wear out on account of photocurrent--the usual rule >> is that you can get an integrated anode charge of about 1000 C/cm**2 of >> photocathode area before the gain drops by ~half. >> >> 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. >> >> Using an air gap between scintillator and tube allows you to keep the >> anode near ground, which is much more convenient, but costs you about >> half your light. (The collection efficiency goes like the etendue, >> which has a factor of n**2 in it.) >> >> Cheers >> >> Phil Hobbs > > Good information. Thanks. > > I'm not planning on heavy use. The idea is to compare the scintillator > againt the Radiacode, and try to measure any Radon gas in the basement. > Then it will probably go into storage. >If you have radon, try running a CRT television for a few hours and then wipe down the screen with a damp piece of tissue that has been folded to about the size of your geiger tube (or its end window if it has one). I find the dust on my CRT screen is quite radioactive but it has a short half-life. I'm guessing it is some polonium isotopes. The dust that collects on the screen doesn't end up in my lungs, so perhaps CRTs are healthier to have in the house than flatscreens.
Reply by ●June 28, 20222022-06-28
On 28/6/22 13:31, Chris Jones wrote:> If you have radon, try running a CRT television for a few hours and then > ... The dust that > collects on the screen doesn't end up in my lungs, so perhaps CRTs are > healthier to have in the house than flatscreens.Not as healthy as having no TV. That crap bypasses the lungs and goes straight to the brain
Reply by ●June 28, 20222022-06-28
On a sunny day (Tue, 28 Jun 2022 13:31:26 +1000) it happened Chris Jones <lugnut808@spam.yahoo.com> wrote in <eCuuK.190184$pqD1.30751@fx01.ams4>:>If you have radon, try running a CRT television for a few hours and then >wipe down the screen with a damp piece of tissue that has been folded to >about the size of your geiger tube (or its end window if it has one). I >find the dust on my CRT screen is quite radioactive but it has a short >half-life. I'm guessing it is some polonium isotopes. The dust that >collects on the screen doesn't end up in my lungs, so perhaps CRTs are >healthier to have in the house than flatscreens.Some CRTs from sets that came in for repair had collected tar from smokers.. nicotine. Wiping clean with alcohol increased brightness considerably :-) So yes, functioned as air filter ;-)
Reply by ●June 28, 20222022-06-28
On a sunny day (Tue, 28 Jun 2022 17:03:04 +1000) it happened Clifford Heath <no_spam@please.net> wrote in <16fcb6d40dd74681$1$391142$70dd7a6b@news.thecubenet.com>:>On 28/6/22 13:31, Chris Jones wrote: >> If you have radon, try running a CRT television for a few hours and then >> ... The dust that >> collects on the screen doesn't end up in my lungs, so perhaps CRTs are >> healthier to have in the house than flatscreens. > >Not as healthy as having no TV. That crap bypasses the lungs and goes >straight to the brainThere are some informative science related programs on (sat) TV Astra1 and there is (at least on the continent) tetelext / ceefax / videotext Caesar: give the people bread and TeeFee or was it games? :-) Its a shame UK dropped Ceefax. no way to see the program schedule other then internet, talk about a DANGEROUS medium ? Just read this group! Radon detectors and test kits are 14 USD upwards on Amazon... I was looking for a sold state PMT diode .. for that tomshardware link I gave, delivery November, about 56 Euro 1 piece I will hang on to my good old PMTs for now, have also many plastic scintillators. Big PMT will likely last to WW3 (2024??). After that all lights up in the dark anyways BTW I have a nice scintillation screen too.
Reply by ●June 28, 20222022-06-28
Mike Monett wrote:> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> Mike Monett wrote: >>> "John Miles, KE5FX" <jmiles@gmail.com> wrote: >>> >>>> On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote: >>>>> My Radiascan Radiacode finally arrived from Russia. After the >>>>> sanctions, I was surprised to see it made it. >>>> >>>> This listing is also very interesting: >>>> >>>> https://www.ebay.com/itm/194659036410 >>>> >>>> Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each. >>>> Wonder how they'd compare to the solid-state CsI(Tl) detector assembly >>>> in the Radiacode unit? >>>> >>>> -- john, KE5FX >>> >>> I tried to order one. Does not ship to Canada. Can you order one and >>> mail it to me? I can pay you via Paypal. Thanks. >> >> For any serious use, I'd budget for a replacement PMT. They age out >> after several years, which is probably why these assemblies were >> replaced. They also wear out on account of photocurrent--the usual rule >> is that you can get an integrated anode charge of about 1000 C/cm**2 of >> photocathode area before the gain drops by ~half. >> >> 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. >> >> Using an air gap between scintillator and tube allows you to keep the >> anode near ground, which is much more convenient, but costs you about >> half your light. (The collection efficiency goes like the etendue, >> which has a factor of n**2 in it.)> > Good information. Thanks. > > I'm not planning on heavy use. The idea is to compare the scintillator > againt the Radiacode, and try to measure any Radon gas in the basement. > Then it will probably go into storage.It ought to work fine for light-duty use like that, though you'll need the PMT supply and bias string. If you know the tube P/N, I can probably tell you what to use. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●June 28, 20222022-06-28
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:> Mike Monett wrote:[...]>> I'm not planning on heavy use. The idea is to compare the scintillator >> againt the Radiacode, and try to measure any Radon gas in the basement. >> Then it will probably go into storage. > > It ought to work fine for light-duty use like that, though you'll need > the PMT supply and bias string. If you know the tube P/N, I can > probably tell you what to use. > > Cheers > > Phil HobbsI don't think the PMT P/N is available. I also assume the bias string is buried inside the assembly. I'll probably have to find the operating voltage by experimenting, a time-honored tradition among hackers. -- MRM
