Measurement of ground-state β−-branching intensities of deformed rare-earth nuclides using a total absorption γ-ray spectrometer

Abstract The utility of the method using a total absorption γ-ray spectrometer system, operating in the 4 πγ-β coincidence mode, to measure ground-state β − -branching intensities of deformed rare-earth fission-product nuclei is discussed. For such nuclei it is demonstrated that, given sufficient information concerning the lower excitation states being populated and their de-excitation modes, precise values can still be obtained for their “ground-state” β − -branching intensities; where here the “ground-state” is defined to include both the true ground state and all excited states below a selected γ-ray discriminator level. Results obtained for 153 Nd, 153 Pm, 154 Nd, 154 Pm(1.7 min), 155 Pm, 156 Pm, 157 Pm, 157 Sm and 158 Sm are presented and compared with existing published data.