Further Study of Several Physical Effects on the Calculation of Angular Distribution Based on Exciton Model

Abstract

In order to understand angular distribution deviation between the calculation based on conventional exciton model and the experimental data of the preequilibrium and equilibrium decays, especially the underestimate of angular distribution by the theory at backward angles, an exact closed form solution to the time-integrated master equation of the exciton model by including the effects of the Fermi motion, the Pauli principle, the finite nuclear size and the refraction of the incident wave at the nuclear surface is applied to the calculation of the angular distribution. In this paper the neutron inelastic scattering cross section for 34 elements at 14.6 MeV have.Jbeen calculated and compared with experimental data measured by Hermsdorf et al..⁽⁵⁾ The results show that because of taking into account the influence of several physical effects mentioned above, the theory can explain the presently existing experimental data, especially solve the problem of the double differential cross section for emitted neutrons with higher energy at backward angles.