Fast Neutron Scattering from Beryllium, Sodium, and Aluminum

Essentially monoenergetic neutrons are scattered from Be, Na, and Al at incident neutron energy intervals of ≲50 keV throughout the range 0.3 to 1.5 MeV. Fast neutron time-of-flight techniques are employed to measure the elastically and the inelastically scattered neutron angular distributions. Differential elastic cross sections are determined and the inelastic excitation cross sections of states in Al at 0.84 and 1.01 MeV and in Na at 0.44 MeV are measured. In addition, the total cross section of Al is measured from 0.3 to 1.5 MeV with resolutions o f ≳ l keV. The experimental results are related to the optical model and the Hauser-Feshbach theory of reaction processes. It is shown that these theoretical concepts can describe the scattering processes in Na and Al despite the marginal applicability of the theories to these light nuclei.