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.