Neutron-Activation Cross Sections

Neutron-activation cross sections have been measured for five target nuclei, ${\mathrm{Hf}}^{180}$, ${\mathrm{Ta}}^{181}$, ${\mathrm{W}}^{186}$, ${\mathrm{Au}}^{197}$, and ${\mathrm{Th}}^{232}$, over a neutron energy range from 0.030 to 4.0 MeV. The experimental results are compared with values calculated from the statistical theory of nuclear reactions. Values of the constant $C_n$ in the approximate level density formula $p_n=C_n\exp \left[2\mathrm{}{\mathrm{}\left(\mathrm{aE}\right)\mathrm{}}^{\frac{1}{2}}\right]$ are obtained for these isotopes from a fit of the calculated and measured cross sections above 1 MeV.