The source in a US market ionization smoke detector is very small, under 1 uCi and Am-241. The material is plated on a small ~1/4" button and typically sealed. They are pretty safe and you could most likely eat it without any issues. However, it is technically illegal to remove the source and use it for other purposes. You could open it up for cleaning and calibration purposes... The ones with higher amounts which are less safe are the old Pyrotronics F5 smoke detectors often sold on ebay for $100+. Those contain multiple sources which in some vintages are known to shed material and contaminate things.
Po-210 is also used in industrial and photographic dust removal products. Check out the Staticmaster brushes for removing dust from film negatives. For legal, exempt quantity sources, direct purchase from Spectrum Techniques is the best, as they are pretty much the only manufacturer around and all the others buy from them. In fact, your source will be shipped directly from them to you no matter who you buy it from. On Fri, Nov 27, 2020 at 4:56 AM SWISSNIXIE - Jonathan F. < jfrech...@gmail.com> wrote: > I advise against using smoke detectors. To detect heir alpha radiation, > you would have to disassemble the source until you get to the radioactive > isotope plated strip - or button - element. This is sort of not allowed, > and also can be very dangerous if you scratch off radioactive material. > From outside the detector you can only detect the Gammas from the Am-241 > Also Quantities are sort of really high in these devices, depending on make > and model (1-100 uCi Am-241). If you really want to have alpha radiation, i > would purchase a Po-210 source from here: > > https://www.spectrumtechniques.com/products/sources/disk-sources-and-source-sets/ > > They are like 60$, 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 <pa...@nixies.us> 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 neonixie-l+...@googlegroups.com. >>> >>> 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 neonixie-l+unsubscr...@googlegroups.com. > 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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