Evidence on the high energy behavior of nuclear level density parameter

Abstract

The nuclear level density parameter (NLDP) plays an important and crucial role in the most widely used phenomenological models that calculate the nuclear level density (NLD) based on the Fermi gas model (FGM). NLDP can be affected by various effects that have been ignored during the FGM calculations. The dependence of NLDP on excitation energy has been predicted by various references and using various relationships that are mainly tested and normalized at low energies by experimental data of low levels. In this research, using nuclear reaction codes and experimental data of the evaporation spectrum of heavy ion 32S + 74Ge reaction leading to 106Cd compound nucleus (CN) at high excitation energies, high energy behaviour of NLDP is investigated and compared with different relationship predictions. By calculating and reducing the contribution of non-equilibrium mechanisms, it is suggested that NLDP behaves increasing and then decreasing at high energies (almost Gaussian-like behavior), contrary to the predictions of all conventional energy-dependent NLDP relations.