Neutron total non-elastic cross sections have been obtained from transmission measurements of 40.3 and 50.4 MeV neutrons on C, O, Ca, and Fe. The results agree within error bars with proton data on the same nuclei. The data are well represented by the relation ${\sigma }_{\mathrm{non}}=\pi {(r_0{A}^{\frac{1}{3}}+\lambda )}^2$, where $r_0=1.21\mathrm{}\pm 0.03$ fm. Comparisons of ${\sigma }_{\mathrm{non}}$ with optical model calculations for C and O show a preference for the parameters of Bassel and Herling, while for Ca both the parameter sets of Patterson and those of Becchetti and Greenlees work reasonably well. None of the parameter sets is entirely satisfactory for Fe. Implications of these data for the isospin dependence of the optical model are discussed.

NUCLEAR REACTIONS C, O, Ca, and $\mathrm{Fe}+n$, $E_n=40.3\mathrm{} \mathrm{and} 50.4$ MeV. Inferred neutron total elastic and non-elastic cross sections. Natural targets.

• Received 6 October 1980

DOI:https://doi.org/10.1103/PhysRevC.23.1015