Monte Carlo calculation of the deexcitation of fission fragments in the spontaneous fission ofCf252

Abstract

The consequences of the evaporation of prompt neutrons and $\ensuremath{\gamma}$ rays from primary fission fragments in the spontaneous fission of $^{252}\mathrm{Cf}$ have been examined by a Monte Carlo method. A semiempirical mass equation and experimental values of total kinetic energies are used to obtain the sum of excitation energies of complementary fragments. The division of this energy between complementary fragments is determined by the two-spheroid model for the scission configuration. The prompt neutron multiplicity distribution gives a value of 3.68 for the average number of prompt neutrons in $^{252}\mathrm{Cf}$(sf). Calculated values of the average number of prompt neutrons as a function of fragments mass are in good agreement with the experimental values. Calculated results for the charge dependence of total $\ensuremath{\gamma}$-ray energies show an odd-even effect, whereas no such effect is apparent in the charge dependence of the average number of neutrons. Mass and charge distributions of secondary fission fragments are also well reproduced in the calculations.NUCLEAR REACTIONS, FISSION $^{252}\mathrm{Cf}$(sf); calculated prompt neutrons and $\ensuremath{\gamma}$ rays. Pairing effect on $\ensuremath{\gamma}$-ray energy.