[ RadSafe ] Bismuth-212 and 727-keV gammas

Leo M. Lowe llowe at senes.ca
Wed Oct 6 13:12:34 CDT 2010


This same issue was discussed previously on Radsafe.  Look in the 
archives in July 2003.

It was suggested at that time that ICRP38 and other normally 
authoritative references were in error about the intensity of the 727 
line,and that the National Nuclear Data Center (NNDC) at BNL should 
be considered as THE most authoritative reference, such as ENSDF at 

Leo Lowe

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of McNaughton,
Sent: 06 October 2010 15:25
To: The International Radiation Protection (Health Physics) Mailing List
Subject: [ RadSafe ] Bismuth-212 and 727-keV gammas

Dear RadSafers

I have a problem with the gamma-spec results for bismuth-212. The
reported concentrations for bismuth-212 are consistently higher than
those for Pb-212, as well as for all the other nuclides in the
thorium-232 decay chain. This is the case for several types of samples,
collected over several years, and analyzed at several different
analytical labs.

I suspect the problem is with the emission probability (or "intensity")
for the 727-keV gamma. Different publications list different numbers for
the emission probability. The numbers range from about 6% to 12%.

I would like to discuss this problem with others who are interested.

Thanks, mike
Mike McNaughton
Los Alamos National Lab
mcnaught at lanl.gov

Leo M. Lowe, Ph.D., P.Phys., CRadP

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