[ RadSafe ] Bismuth-212 and 727-keV gammas

Arvic Harms Arvic.Harms at npl.co.uk
Wed Oct 6 10:30:40 CDT 2010

Dear Mike,

Please check out page 4 and 5 of


The numbers range from 6.3% to 7.6% (nine nuclear data evaluations
between 1960 and 1992). 

The DDEP recommended value is 6.74(12)%.

Kind regards,

Arvic Harms

Dr Arvic Harms
National Physical Laboratory
Hampton Road
Teddington TW11 0LW
United Kingdom
E-mail: arvic.harms at npl.co.uk 

-----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
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