MASS DISTRIBUTION IN THERMAL NEUTRON FISSION OF 239Pu

Abstract

Improved radiochemical techniques have been used to study the distribution in mass of the fission fragments resulting from thermal neutron fission in 239Pu.Disintegration rates and half-lives were determined by measurement with a 4πβ gas flow proportional counter. Further identification of the nuclides was obtained by gamma scintillation spectrometry. The flux intensity during irradiation was monitored by the 59Co(n,γ)60Co reaction.The absolute fission yields of 89Sr, 90Sr, 91Y, 95Zr, 99Mo, 103Ru, 106Ru, 105Rh, 109Pd, 1I2Pd, 111Ag, and 115Cd in the light mass peak and 127Sb, 131I, 133I, 132Te, 137Cs, 140Ba, 141Ce, 143Ce, 144Ce, 147Nd, and 156Eu in the heavy mass peak have been measured. In addition, the independent yields of 82Br, 124Sb, 126Sb, and 136Cs were obtained.