REFINEMENTS OF THE NUCLEON-EXCHANGE TRANSPORT MODEL FOR THE EMISSION OF HARD PHOTONS AND NUCLEONS

A previously developed nucleon-exchange transport model for preequilib rium neutron and hard photon emission is extended to include proton em ission. Several refinements including diffuse ground-state nucleonic m omentum distributions and quantal rather than classical bremsstrahlung production are added. The incorporation of a diffuse momentum distrib ution improves the reproduction of experimental spectra and multiplici ties, particularly at low bombarding energies. Quantal bremsstrahlung enhances the production of high-energy photons. The effect of decelera tion of the colliding nuclei during the propagation of the jetting par ticles through the receptor nucleus is explored. The effect of preequi librium emission on the evaporation residue and its dependence on entr ance channel mass asymmetry is studied. The number of preequilibrium p articles emitted is inconsistent with some previous analyses of evapor ation residue spectra.