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RE: Co-57 Gamma Constant
I'm not sure if you got the answer to your question or not. Here's what I
know from the Engineering Compendium. The compendium portion you cited is
actually an article by O. Suschny. There are some 5.5 pages of nuclides,
half-lives, types of decay and gamma energies listed in that table. His
citation for the gamma constants in that table states: "Most gamma values
have been taken from 'The Radiochemical Manual' published by the
Radiochemical Centre Amersham." To get to the actual data to answer your
question, you would have to lay your hands on - The Radiochemical Manual,
2nd Ed, from The Radiochemical Centre, Amersham, Buckinghamshire, 1966 which
I do not have access to.
As an educated guess, I would say that the value in that table was obtained
by Amersham in their labs using available dosimetry and measurement
equipment. Similar values were obtained in that manner such as for other
sources used to study Mossbauer effects (e.g. sn-113).
Good Luck.
The opinions expressed are mine, all mine...
I'm with the government, I'm here to help
Daren Perrero
perrero@iema.state.il.us
-----Original Message-----
From: Roy A. Parker [mailto:royaparker@COMPUSERVE.COM]
Sent: Monday, May 17, 2004 4:02 PM
To: RADSAFE
Subject: Co-57 Gamma Constant
There seems to be two prevailing Gamma Constants in the literature for
Co-57: 0.15 RHM/Ci and 0.09 RHM/Ci. The first Gamma Constant, 0.15 RHM/Ci,
seems to be derived from ORNL/RSIC-45/R1 Specific Gamma-Ray Dose Constants
for Nuclides Important to Dosimetry and Radiological Assessment. The
second,
0.09 RHM/Ci, seems to go back to Jaeger, R. G., et al., Engineering
Compendium on Radiation Shielding, Vol. 1, (New York: Springer-Verlag,
1968), pp. 21-30. I am trying to understand the difference between the two
values. The ORNL/RSIC value of 0.15 RHM/Ci is strictly computational. I do
not have a copy of Jaeger. Is his value based on actual measurement and is
it a lower value because of source size (self absorption) and/or attenuation
because of encapsulation or covering on the source?
Roy A. Parker, Ph.D.
roy@royparker.org
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