Fast-Neutron Cross Sections of Elemental Bismuth

Neutron total cross sections of elemental bismuth were measured with broad resolutions from 1.2 to 4.5 MeV to accuracies of ∼1%. Neutron differential elastic scattering cross sections were measured from 1.5 to 4.0 MeV at incident neutron energy intervals of ≲0.2 MeV over the scattered neutron angular range ∼20 to 160 deg. Differential neutron cross sections for the excitation of observed states in bismuth at 895 ± 12, 1606 ± 14, 2590 ± 15, 2762 ± 29, 3022 ± 21, and 3144 ± 15 keV were determined at incident neutron energies up to 4.0 Me V. The measured values were interpreted in terms of an optical-statistical model.