[ RadSafe ] Bismuth-212 and 727-keV gammas

[Bradshaw, Keith kzb]

Mike, we get consistent Th-232 decay series results using DDEP or LARA nuclear data.  In these, the 727keV Bi-212 gamma emission probability is 6.74%.

http://laraweb.free.fr/

http://www.nucleide.org/DDEP_WG/DDEPdata.htm

This is also the same in JEFF 3.1.  In passing I notice the Table of Isotopes value is 6.58%.

http://ie.lbl.gov/education/isotopes.htm

So that is not a million miles away either.  I've not seen a value of 12% in any of our data sources here.

Personal views only

Keith Bradshaw


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of McNaughton, Michael
Sent: Wednesday, October 06, 2010 3:25 PM
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
505-667-6130
mcnaught at lanl.gov
_______________________________________________
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://health.phys.iit.edu/radsaferules.html

For information on how to subscribe or unsubscribe and other settings visit: http://health.phys.iit.edu

This email contains confidential information. The contents must
not be disclosed to anyone else except with the authority of the sender.
Unauthorised recipients are requested to maintain this confidentiality and
immediately advise the sender of any error or misdirection in transmission.

The following notice applies to emails originating in the UK.
E-mails sent on behalf of AMEC are sent on behalf of the relevant AMEC
company below. These are registered in England and Wales with registered
office at Booths Park, Chelford Road, Knutsford, Cheshire WA16 8QZ and
number as shown: AMEC plc 01675285, AMEC Group Limited 04612748,
AMEC Capital Projects Limited 02804109, AMEC Earth and Environmental UK
Limited 04987981, AMEC Nuclear Holdings Limited 03725076,
AMEC Nuclear M & O Limited 05664844, AMEC Nuclear UK Limited 01120437,
AMEC Nuclear International Limited 03260477, AMEC Nuclear Projects
Limited 05664962  and National Nuclear Corporation Limited 02290928