Gamma Spectrometry Forum

Hello,
I have from GB a spark gap and do not understand why I have absolutely no pulses . Who has an explanation.
The image shows the tube. Even with a Geiger counter is no radiation to detect. Who has a statement?
Peter

Hello Peter,
cs137 has a half life time of about 30 years, if the tube was produced in early 50's means that the radioactive amount is now less then 1/4 of the original, maybe it's just to weak to be measured.

Mattia

Hallo Peter
I have also from GB such spark plugs.
But i have put 4 together and this is working. With only one, i have also Problems. As MathiaB wrote, only 1/4 of original. But 4 or 5 together could make the thing.
Radioactivity is very weak with only one.
There is another problem with this plugs. Not all contain C137 anyway.
If You could get this things cheap,buy some more and try.

Hello Gerhard,

do you think that 4 times zero is more than zero ? take a look to the spec. Peter

Hallo, Peter
This is a nice idea. But,if You believe it or not, with only one, i got also no indikation. Same i observed trying Lutetium crystals.
With only one, no indikation, with 5 together,i got a spectrum.
Maybe the Gaps have zero C137, than You are right and 4 together are also zero.But, if the plug has a weak radiation,far below for the counter, more of them could help.
It ist interesting,because i have absolutly the same,also from GB.The brown spot inside is the C137.
But i found, that some of such gaps have instead of C137 other radiaktive Components,such as Radium or Polonium 210.
But Yours seem to have C137,because it is the same,i have.
VALVE TUBE CK1098-1 SPARK GAP New old stock Raytheon from ebay uk

If you want a nice and really hot cs137 tube look on the bay for "TG 36 tube" from US.. I recently bought one of those and believe me, the custom to Italy was a 11€ charge but it worth the extra money.
Mattia

@MattiaB,
This is a good idea, but it is not possible for me. Our duty is extremely accurate and will not give me the part. Probably I still get a complaint. I had trouble in the past with harmless parts (for microscopy) from USA. Here is my calibration. 250 gr KCl and the background without shielding.

Peter

Why not get a 0.25 uCi (9.25 kBq) source from Spectrum Techniques ?
The exempt limit is 10 kBq (U.S. NRC 10 CFR Part 30.18, CFR 49.173, IATA_DG #10, IAEA TS-R-1, etc.) so such shipping doesn't require any special handling, approvals, licenses.
Price for the source was ~120 USD (incl. shipping), customs fee ~20 EUR (VAT, exempt from customs duty).
Their ordering system is older than the source's half-time, but they work well.
They ship it with a proper invoice and certificate. At our (strict) customs I declared it as is and there was absolutely no problem. I believe the same rules will apply for your customs too (we're both in the EU).

You should look also for
Eckert & Ziegert, they also offer check sources and they are in Germany.

Does anyone have experience with Eckert & Ziegert ? Do they talk (and ship) to individuals too ?