The Decay of 137Cs Determined by β-Ray Spectrometry

The internal conversion coefficients of the 662 keV transition in 137Ba have been determined by the PBS method using an iron-free, double-focusing β-ray spectrometer. The results, with overall 68% confidence limits, were αT = 0.1092 ± 0.0008 and αK = 0.0888 ± 0.0007. In addition, the intensities per disintegration of the high-energy β-branch and of the 662 keV γ-ray were determined to be (6.21 ± 0.07)% and (84.56 ± 0.08)% respectively, and the value (513.89 ± 0.26) keV was obtained for the endpoint energy of the inner β-branch.