The Use of Beta-Strength-Function Data to Obtain Average Decay Energy Values for Short-Lived Fission Product Nuclides

Abstract

In this paper, the authors point out that data from earlier experiments carried out to measure beta-strength functions for short-lived fission products can also be used to provide average beta- and gamma-decay energy values for these nuclides. In their evaluation of decay data for the ENDF/B-V fission product file, the authors have used this approach as a means of deducing average decay energy values for a number of these isotopes for which experimentally based average values would otherwise not have been available. The methods employed are discussed, and the results for the average beta-decay energies per decay, (E..beta..), are presented. Where available, (E..beta..) values deduced from decay scheme studies and from direct beta-spectrum measurements are given for purposes of comparison. Evidence is presented that suggests that the conventional decay scheme studies may not be a reliable source of average decay energy data for nuclides with large Q..beta.. values. The authors propose that different types of experimental measurements, possibly involving total absorption techniques (of which the beta-strength work treated here might be considered as one example), may provide a better means of producing this important information.