Concerning the time dependence of the decay rate of 137 Cs

Authors

J H. Jenkins, Purdue University
E Fischbach, Purdue University
D Javorsek II, Air Force Test Center
R H. Lee, U.S. Air Force Academy
P A. Sturrock, Stanford University

Date of this Version

2013

Citation

Applied Radiation and Isotopes 74, 2013

Comments

U.S. Government work

Abstract

The decay rates of eight nuclides (⁸⁵Kr, ⁹⁰Sr, ¹⁰⁸Ag, ¹³³Ba, ¹³⁷CS, ¹⁵²Eu, ¹⁵⁴Eu, and ²²⁶Ra) were monitored by the standards group at the Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany, over the time frame June 1999 to November 2008. We find that the PTB measurements of the decay rate of 137 Cs show no evidence of an annual oscillation, in agreement with the recent report by Bellotti et al. However, power spectrum analysis of PTB measurements of a 133Ba standard, measured in the same detector system, does show such evidence. This result is consistent with our finding that different nuclides have different sensitivities to whatever external influences are responsible for the observed periodic variations.