An old gas lamp mantle is good enough for the purpose, as its main emission is alpha particles. It must be an old one because those ones use thorium oxide to get its distinctive bright, while new ones don't use thorium. I keep 3 of them, which I got from a local auction site, in a small ziploc bag that saves me from touching the mantles themselves.
On Friday, November 27, 2020 at 8:10:19 AM UTC-3 Sgitheach wrote: > Would just a chunk of granite (or a granite kitchen worktop if you have > one) be good as a cheap starting point? > On 27/11/2020 10:56, SWISSNIXIE - Jonathan F. wrote: > > I advise against using smoke detectors. To detect heir alpha radiation, > you would have to disassemble the source until you get to the radioactive > isotope plated strip - or button - element. This is sort of not allowed, > and also can be very dangerous if you scratch off radioactive material. > From outside the detector you can only detect the Gammas from the Am-241 > Also Quantities are sort of really high in these devices, depending on make > and model (1-100 uCi Am-241). If you really want to have alpha radiation, i > would purchase a Po-210 source from here: > > https://www.spectrumtechniques.com/products/sources/disk-sources-and-source-sets/ > > They are like 60$, safe and legal to handle. Only disadvantage is short > half life of 138 days. > You also can find high power Po-210 sources here: > https://www.imagesco.com/geiger/radioactive-sources.html > > Paul Andrews schrieb am Donnerstag, 26. November 2020 um 17:00:06 UTC+1: > >> And by 'alpha', I meant 'beta'. I actually did mean alpha, but I was >> wrong. Still my old Geiger/Muller tube couldn't detect anything from these >> nixies, so at least I can now detect beta particles. Now I need to find an >> alpha source! Smoke detectors apparently. >> >> On Thursday, November 26, 2020 at 10:27:17 AM UTC-5 Pramanicin wrote: >> >>> Still a bit of juice left! >>> >>> Sent from my iPhone >>> >>> On Nov 26, 2020, at 07:25, Paul Andrews <[email protected]> wrote: >>> >>> Finally got an alpha detector for my GK-Mini geiger counter. First >>> picture is a regular nixie tube. Second is one doped with Kr85 >>> <IMG_5681.JPG> >>> >>> >>> <IMG_5683.JPG> >>> >>> >>> On Friday, November 6, 2020 at 9:20:54 AM UTC-5 SWISSNIXIE - Jonathan F. >>> wrote: >>> >>>> Could also be Ra-226 on the 6140 >>>> >>>> gregebert schrieb am Mittwoch, 4. November 2020 um 16:32:02 UTC+1: >>>> >>>>> Maybe it's Thorium, used in the filaments. >>>>> >>>>> On Wednesday, November 4, 2020 at 4:13:16 AM UTC-8 Paolo Cravero wrote: >>>>> >>>>>> Hi. >>>>>> Let me add two pictures and a story. >>>>>> >>>>>> Lately I picked up locally a bunch of small CRTs (2BP1, that also fit >>>>>> in the vintage tuner currently on eBay, plus a Marantz) and the guy had >>>>>> a >>>>>> few NIB tubes too. I was looking for gas-filled ones and that resulted >>>>>> in a >>>>>> W.E. 6167 dekatron, some 0B2WA and some W.E. 6140/423A. Of particular >>>>>> interest was the 6140 shown in the picture whose box mentions Kr85, but >>>>>> no >>>>>> symbol on the glass. >>>>>> When I came home I checked with a Geiger counter and SBM-20 probe >>>>>> (hard beta and gamma particles) these tubes and the 6140 from 11/61 >>>>>> shows >>>>>> no action. Same goes for other 6140 except for one, much older from >>>>>> 12/52 >>>>>> marked 423A. Neither the box nor the glass carry any warning sign, but >>>>>> this >>>>>> tube hits >600 CPM vs 40 CPM background when put close to the SBM-20 >>>>>> probe >>>>>> (it's not the right way to measure radiation, but it's cool :) ). There >>>>>> is >>>>>> definitely something else than Kr-85 in there! I have blurred pics of it >>>>>> and it has been stored away from home. >>>>>> >>>>>> As already mentioned, Nixies did contain Kr-85 and I knew I had one >>>>>> clearly marked. It's a Burroughs Self-Scan display that probably needed >>>>>> some "doping" to handle the almost 1 MHz scan rate. BTW, it contains gas >>>>>> and I might never use it, so if someone wants to experiment with >>>>>> self-scan >>>>>> contact me off the list. >>>>>> >>>>>> One question for the knowledgeable people in here. I have some >>>>>> Mullard Nixies marked "Kr-0A": has it got something to do with Kr-85? I >>>>>> can't check with the Geiger since my probe does not detect Kr-85 >>>>>> leftovers. >>>>>> >>>>>> So, if you are on the hunt for active tubes, better look for unmarked >>>>>> pre-1960 editions and carry a Geiger counter with you ;) >>>>>> >>>>>> Paolo >>>>>> >>>>> -- >>> >>> You received this message because you are subscribed to the Google >>> Groups "neonixie-l" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> >>> To view this discussion on the web, visit >>> https://groups.google.com/d/msgid/neonixie-l/3f26a1e5-5836-4ff5-b1ea-f95fab53151cn%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/neonixie-l/3f26a1e5-5836-4ff5-b1ea-f95fab53151cn%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> <IMG_5683.JPG> >>> <IMG_5681.JPG> >>> >>> -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/d65b18e5-dbaf-4d6c-8d86-fc88fbf2f7bdn%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/d65b18e5-dbaf-4d6c-8d86-fc88fbf2f7bdn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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