Energetic photons from intermediate energy proton- and heavy-ion-induced reactions

The cross section for emitting high energy gamma rays in heavy-ion collisions is calculated in a model based on the Boltzmann-Uehling-Uhlenbeck equation. The elementary production cross section is assumed to be neutron-proton bremsstrahlung. Comparison is made with experimental data at bombarding energies from 20 to 84 MeV/nucleon. The calculations are found to roughly reproduce the energy spectrum, bombarding energy dependence, and angular distribution. From the numerical analysis we conclude that the production of high-energy \ensuremath{\gamma} rays is limited to the very early stage of the collision.