Nuclear-Structure Effects in High-Energy (p,n) Reactions

The cross sections for the ($p,n$) reaction at 370 MeV with ${\mathrm{Ca}}^{44}$, ${\mathrm{Ca}}^{48}$, ${\mathrm{V}}^{51}$, ${\mathrm{Cr}}^{54}$, and ${\mathrm{Ag}}^{109}$ have been measured to be 2.0±0.2, 2.3±0.3, 2.2±0.2, 0.72±0.15, and 1.45±0.15 mb, respectively. These results, along with others in the literature, are analyzed in terms of a semiclassical model that considers the direct ejection of the least-bound and the next-least-bound neutrons from the target nucleus by a quasielastic scattering of the incident proton. The spatial distribution of the struck neutrons is taken as that given by the appropriate harmonic-oscillator wave functions. Estimates of the binding energies of neutrons in the first level below that which is least bound result from this analysis.