The choice of the optimum terms for semi-empirical description of s-wave neutron resonance level densities

Abstract

This paper presents a function describing the dependence of the neutron resonance level density ρ on the neutron number N in the target nucleus. The function describes quite well, with an accuracy of one order, the experimental data for 284 nuclides. Moreover, it adequately describes the general tendency and shell model effects for magic nuclei and for nuclei close to magic ones. The achieved agreement between the values obtained from the proposed description and the experimental data ρexp can be improved if the ρexp values are normalized energetically and reduced to a narrow range of angular momentum J.