Mass Spectrometric Studios of Fission Products Pu239 and U235

Abstract

The absolute cumulative yields of forty-one light and heavy fragments farmed in the thermal neutron fission of Pu239 have been measured with a mass spectrometer twins the isotope dilution technique. These include the yields of isotopes of rubidium, strontium, zirconium, molybdenum, ruthenium, cesium, cerium, neodymium and samarium. The yields of twelve light fragments formed in the thermal neutron fission of U235 have also been reported. A comprehensive study of fission yields requires a knowledge of carrier-free separation techniques, accurate half-lives and neutron capture crocs sections of the various fission nuclides. Lew procedures for the carrier—free analysis of the elements of zirconium, molybdenum and ruthenium have been developed. Also the half-lives of Sr89 and Zr95 and the thermal neutron capture cross sections of Xe135 and Sm149 were determined. A comparison of the yields of the light and heavy mass fission products of Pu239 has made possible a more detailed understanding of neutron emission from the primary fragments of fission.