THE RELATIVE ABUNDANCES OF NEODYMIUM AND SAMARIUM ISOTOPES IN THE THERMAL NEUTRON FISSION OF U235 AND U233

Abstract

The relative fission yields of neodymium and samarium isotopes have been measured with a mass spectrometer for samples of natural uranium and U²³³ that had been irradiated with moderated neutrons. The cross sections for neutron capture by Sm¹⁴⁹ and Sm¹⁵¹ have been determined to be 66,200 ± 2500 barns and 12,000 barns respectively, relative to the cross section of a B¹⁰ monitor. The half-lives of Pm¹⁴⁷ and Sm¹⁵¹ have been evaluated to be 2.52 ± 0.08 yr. and ~93 yr., respectively, from samarium fission yield data for samples differing in age by seven years.