Mass, shell, and even-odd effects in radiative capture reaction.

Abstract

This paper investigates the mass, shell, and even-odd effects in the nonstatistical and statistical contributions to the radiative nucleon capture reactions. The (n,\ensuremath{\gamma}) cross sections for 32 even-neutron target nuclei were studied at ${\mathit{E}}_{\mathit{n}}$ of 0.1 to 3 MeV. The results indicate that the nonstatistical capture cross sections do not present any remarkably varying pattern with mass number. The statistical capture cross sections, which depend strongly on the level density, display marked mass, shell, and even-odd effects. The nonstatistical fractions show prominent downward tendency with mass number, as well as the shell effect.