Impact of Nuclear Level Densities on Astrophysical Reaction Rates

Nuclear Level Densities (NLDs) are key inputs for calculating reaction rates for uses in astrophysics, medical physics, and industry. The NLD is defined as the number of energy levels per energy interval for a nucleus, which increases as energy increases. We calculate NLDs for various energy levels using the Moments Method. We then use our results and the program TALYS in order to calculate nuclear reaction rates in astrophysical environments. More specifically, we calculate the cross sections of (n,gamma) reactions, describing the probabilities of the reaction occurring under given conditions. These reactions take place in environments with an abundance of neutrons, such as neutron stars, core collapse supernovae, and neutron star mergers. We compare our cross sections from TALYS with available experimental data as well as other theoretical models, including the Fermi Gas model and the Constant Temperature model.