[ RadSafe ] Europium-252 identified instead of Bismuth-214

[Lidia Silva]

Hi Mike,

Just a curiosity: are you using NaI ou HPGe detectors?

If you can cross-check the decay probabilities with the peak areas, you should be able to do the same for the 1408 keV line; if your peak is too small, then acquire the spectrum for a longer period of time.

Unless you have a huge Compton continuum, the 121.7 keV peak of Eu-152 should be visible (if this radionucle is present in the sample).

Anyway, the problem of incorrect radionuclide identification is frequent: the "standard" libraries have a lot of radionuclides, with overlapping energies. A good approach is to build your own library, for the purpose of your measurements.

I hope this helps. Best regards,

Lidia

________________________________________
De: radsafe-bounces at radlab.nl [radsafe-bounces at radlab.nl] Em Nome De Michael McNaughton [mcnaught at lanl.gov]
Enviado: terça-feira, 24 de Março de 2009 15:58
Para: radsafe at radlab.nl
Assunto: [ RadSafe ] Europium-252 identified instead of Bismuth-214

Dear Radsafers

I have some soil samples for which I think Bismuth-214 is incorrectly
identified as Europium-252. Is this a well-known problem?

The gamma-spec software found a small peak near 1408 keV and reported
it as 0.4 pCi/g of Europium-252, though it did not find any other
Europium-252 peaks. The sample contains about 3 pCi/g of Bismuth-214,
and has large peaks at 609 keV, 1120 keV, and 1765 keV, so I think
the small peak at 1408 keV is probably from Bismuth 214. The relative
sizes of the peaks correspond to the relative probabilities of decay
for Bismuth-214.

I would be interested in discussing this problem with gamma-spec experts.

Thanks, mike

Mike McNaughton
Los Alamos National Lab.
email: mcnaught at LANL.gov or mcnaughton at LANL.gov
phone: 505-667-6130; page: 505-664-7733

_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood the RadSafe rules. These can be found at: http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings visit: http://radlab.nl/radsafe/