[ RadSafe ] Bismuth-212 and 727-keV gammas

[McNaughton, Michael]

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
505-667-6130
mcnaught at lanl.gov