The Inelastic Scattering of Neutrons

TLDR

The study examines total and differential cross sections for neutron inelastic scattering, assuming a sufficiently excited compound nucleus that justifies use of the statistical model. The authors supply tables enabling calculation of angular distributions for neutron scattering with incident and emergent angular momenta up to 3ħ. The results show that when the statistical model applies to the residual nucleus, the angular distribution of inelastically scattered neutrons is isotropic, whereas limited excitation levels produce anisotropy, and total cross‑section calculations illustrate sensitivity to the excited state quantum numbers.

Abstract

The total cross section and the differential cross section for the inelastic scattering of neutrons are considered. It is assumed that the compound nucleus is sufficiently excited so that the statistical model may be applied. If the statistical model may be applied as well to the residual nucleus, it is shown that the angular distribution of the inelastically scattered neutrons is isotropic. If only a few levels of the target nucleus can be excited, the angular distribution is anisotropic. Tables are provided which permit the calculation of the angular distribution if the incident and emergent neutron angular momenta are less than or equal to $3\ensuremath{\hbar}$. Examples of the evaluation of total cross sections are given, providing examples of the sensitivity of the results to the quantum numbers of the excited state.