The delayed neutrons from neutron-induced fission in ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$, ${}_{}{}^{238}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{241}{}_{}{}^{}\mathrm{Am}$, ${}_{}{}^{242}{}_{}{}^{}\mathrm{Am}_{}^m{}_{}{}^{}$, ${}_{}{}^{245}{}_{}{}^{}\mathrm{Cm}$, and ${}_{}{}^{249}{}_{}{}^{}\mathrm{Cf}$ were studied for the first time; those from ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{239}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{241}{}_{}{}^{}\mathrm{Pu}$, and ${}_{}{}^{242}{}_{}{}^{}\mathrm{Pu}$ were measured again. The data were used to develop an expression for the prediction of the absolute delayed neutron yield, and the prediction of delayed neutron emission with time. This approach accurately predicts observed delayed neutron yields and decay characteristics. A fission product yield model was used in conjunction with delayed neutron emission probability to analytically predict delayed neutron characteristics. The results of this analysis are in excellent agreement with experimental values.

RADIOACTIVITY Delayed neutron yield from thorium and transuranium elements, measured and calculated values.

• Received 5 September 1980

DOI:https://doi.org/10.1103/PhysRevC.23.1113