مشخصات پژوهش

A stochastic approach based on two-dimensional dynamical model was used to simulate the fission process of the excited compound nucleus produced in reaction. In the dynamical calculations, the elongation parameter of the nucleus was used as the first dimension and the projection of the total spin of the compound nucleus onto the symmetry axis, , considered as the second dimension. The average pre-fission multiplicities of neutron, light charged particles and the total kinetic energy of the fission fragments were calculated for and the results of calculations compared with the experimental data over a wide range of excitation energy. In the dynamical calculations, dissipation was generated through the chaos weighted wall and window friction formula and the dissipation coefficient of , , was considered as a free parameter and its magnitude inferred by fitting measured data on the average pre-fission multiplicities of neutron and proton for the compound nucleus . It was shown that the results of calculations are in good agreement with the experimental data by using the dissipation coefficient of in the range . It was also shown that the results of calculations with provide a better agreement with the experimental data than with a deformation-dependent dissipation coefficient. Furthermore, it was also shown that deferences between the results of calculations for the total kinetic energy of the fission fragments calculated by using different values of dissipation coefficient of are small.