Calculations of Inelastic Scattering of Neutrons by Heavy Nuclei

Neutron-scattering cross-section data between 0.1 and 3.0 MeV for U, Th, Bi, Pb, Au, W, and Ta have been fitted using a local, spherical, spin-dependent optical potential with a minimum number of parameters. Total cross sections and differential elastic angular distributions, corrected to include compound elastic scattering, are used. With the "entrance-channel" parameters thus determined, the Hauser-Feshbach statistical model gives reasonable predictions of the cross sections for inelastic scattering of neutrons by ${\mathrm{U}}^{238}$, ${\mathrm{Th}}^{232}$, ${\mathrm{Bi}}^{209}$, ${\mathrm{Pb}}^{208}$, ${\mathrm{Au}}^{197}$, ${\mathrm{W}}^{184}$, and ${\mathrm{Ta}}^{181}$. The latitude in fitting entrance-channel data allowed by the optical-model parameters is sufficient to mask effects arising from nonlocality, deformation, and width distributions. To a very high degree, this relatively simple model is shown to be adequate for the presently available data.