Independent yields of 150Pm in the thermal neutron-induced fission of 233U, 235U, 239Pu and 249Cf and cross-section for the 149Pm( n, γ) 150Pm reaction

Abstract

Independent yields for the shielded nuclide 150Pm were determined in the thermal neutron-induced fission of 233U, 235U, 239Pu and 249Cf using radiochemical techniques. They were found to be (2·6±0·2)×10 −4%, (3±1)×10 −5%, (1·15±0·07)×10 −3% and (1·9±0·2)×10 −2%, respectively; these values correspond to empirical Zp values of 58·66, 58·31, 58·79 and 59·18, respectively, if a Gaussian charge dispersion function with a σ of 0·56 is used. A comparison of the Zp values for 150Pm with Zp values for other nuclides in the thermal neutron-induced fission of several actinide isotopes is given. The cross-section for 149Pm( n, γ) 150Pm in a swimming pool reactor neutron spectrum was found to be (1630±160) barn.