This is demonstrated by the following listing. For each minor line of Co-57, I have listed the energy, the intensity from the WWW Table of Radioactive Isotopes (based on a 1992 ENSDF compilation), and the intensity from the INEL On-Line Gamma-ray Spectrum Catalogue (based on a July 2000 ENSDF compilation).
Date: Wed, 19 Dec 2001 15:39:20 +1100
From: LAM HOI CHING <
lamhc@HKUSUA.HKU.HK>
Subject: Identification of gamma peak 1576 keV
Dear Radsafers,
Subject :Identification of 1576 keV gamma peak
Our department recently purchased a 10mCi Co57 flood source for gamma
camera QA purpose. In using a Ge MCA detector, several gamma peaks have
been recorded other than the usual 122keV and 136 keV for Co57.
There are peaks for
Co58 : 810keV , 864
Co56 (keV) : 846.7, 977.2,
1037.9,1175.1,1238.3,1360.3,1442.5,1771.4,1810.8,
&n!
bsp; 1963.6,2015.3,2034.8
Co57 (keV) : 339.7,352.3,366.6,569.9,692
Question 1:
An unclassified peak of 1576.7 keV (±0.2keV) has been detected.
What is that unknown peak ?
Question 2:
I have used the gamma yield% values from LLNL website ( nuclide search
: Co57) noticed that the yield% values for 569.9 keV and 692 keV have given
resultant Co57 activity 2 times larger in activity value than those
calculated from 339.7,352.3 and 366.6keV.
Thank you for any possible suggestions or answers.
Best regards
John Lam, Physicist, Eastern Hospital, Hong Kong