Population of the 283 keV level of ¹³⁷Ba by the β decay of ¹³⁷Cs

Abstract

The gamma spectrum of 137Cs was measured by means of a low-level shielded and Compton-suppressed HpGe spectrometer. The gamma line with the energy 283.4 keV and absolute intensity of 5.3(14)×10-6 was found. It was concluded that the 283.4 keV intermediate level in 137Ba [seen earlier in (n,n′ γ) measurements] is populated in the β decay of 137Cs with the comparative half-life of log ft= 15.3(3).