[ RadSafe ] Ba 133 dose calibrator accuracy

Michael Bohan mike.bohan at yale.edu
Tue Apr 10 17:16:42 CDT 2007

Hello Gary and RadSafers,

Of course, I'm assuming that you have zero'ed and background corrected 
your dose calibrator first...

The next most likely reason is your decay correction of the Ba-133 
source.  Some references do not give the correct half-life for Ba-133.  
Currently, NIST lists the half-life for Ba-133 of 3854.7+/- 2.8 days 
(10.55 years).  Some references list 7.2 years (the Old Rad. Health 


Also, if you have a very old Ba-133 reference source there may be some 
contaminant(s) that may be adding to the expected value.


Mike Bohan, RSO
Yale-New Haven Hospital
Radiological Physics
20 York St. - WWW 204
New Haven, CT 06510
Tele: (203) 688-2950
Fax: (203) 688-8682
Email: mike.bohan at yale.edu

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