Low-energy neutron interaction with even-even nuclei and coupled channel optical model

Abstract

We revised a description of low-energy neutron cross section data for even-even spherical nuclei in terms of the coupled channel optical model (CCOM). It is shown that two-phonon version of this model allows to obtain a unified description of these data assuming slight changes of nuclear diffuseness parameter for magic and near-magic nuclei. Neutron strength functions and scattering lengths for even-even spherical nuclei are also calculated using the same model. Results of these calculations are in a good agreement with experimental data. NpNn-systematics of inelastic neutron scattering on even-even nuclei is proposed. This systematics combined with CCOM calculations of neutron cross sections presents an additional method for finding nuclei with semimagic numbers of nucleons.