[ RadSafe ] Bismuth-212 and 727-keV gammas
HHedge at GeoSyntec.com
HHedge at GeoSyntec.com
Wed Oct 6 19:28:30 CDT 2010
If the Thorium series activity is high in the samples you could be including a minor Ac-228 gamma line at 726.863 (15) keV, yield 0.62 (8) % in the reported activity of Bi-212. This data was taken from NuDat2 (http://www.nndc.bnl.gov/nudat2/indx_dec.jsp). It lists the Bi-212 peak as 727.330 (9) keV, yield 6.67 (9) %.
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Date: Wed, 6 Oct 2010 16:30:40 +0100
From: "Arvic Harms" <Arvic.Harms at npl.co.uk>
Subject: Re: [ RadSafe ] Bismuth-212 and 727-keV gammas
To: "The International Radiation Protection (Health Physics) Mailing
List" <radsafe at health.phys.iit.edu>
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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)%.
Dr Arvic Harms
National Physical Laboratory
Teddington TW11 0LW
E-mail: arvic.harms at npl.co.uk
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
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
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.
Los Alamos National Lab
mcnaught at lanl.gov
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