Ni58(n, p)Co58Cross Section for Neutrons of Energies between 2.2 and 3.6 Mev

The relative cross section for ${\mathrm{Ni}}^{58}(n, p){\mathrm{Co}}^{58}$ has been measured by an activation method for neutron energies of 2.2 to 3.6 Mev. The absolute cross section at 3.55-Mev neutron energy is found to be 195±30 mb by comparing the intensity of the 810-kev gamma ray of ${\mathrm{Co}}^{58}$ with the amount of ${\mathrm{Si}}^{31}$ formed in the ${\mathrm{P}}^{31}(n, p){\mathrm{Si}}^{31}$ reaction, which has a previously known cross section of 96.2±9.0 mb. The cross section rises from 140 mb at 2.2 Mev to a maximum value of 214 mb at 3.0 Mev. Observed cross sections are compared with the predictions of the statistical theory of nuclear reactions by using a square well potential and a diffuse edge potential. In neither case could a satisfactory agreement with experimental data be obtained.