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
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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
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