Gamma emission probabilities in the decay of 241Pu and 237U, determined from the in-growth of 241Am

Abstract

The decay rate of chemically purified 241Pu source material was determined by observation of the in-growth of the 59.5-keV γ-ray from the decay of the 241Am daughter over a period of 154 days. From the resulting source calibration and measurements of γ intensities, emission probabilities were determined for four γ-rays from the decay of 241Pu and for eight γ-rays from the decay of its 237U daugther. The uncertainties in the emission probabilities were less than 1% for the 148-keV γ-ray from 241Pu, and for the 65-, 165-, 208-, and 268-keV γ-rays from 237U. Uncertainties for the remaining γ-rays were between 1.0 and 4.2%. The applicability of the various transitions to the quantitative assay of 241Pu is discussed.