2π-Differential Recoil Study of theCu65(p,pn)Cu64Reaction

Abstract

The $2\pi$-differential recoil range of the ${\mathrm{Cu}}^{65}\mathrm{}(p,pn)\mathrm{}{\mathrm{Cu}}^{64}$ reaction has been determined with incident protons of 130 and 396 MeV. The number of ${\mathrm{Cu}}^{64}$ atoms which recoiled from copper targets about 10 μg/${\mathrm{cm}}^2$ thick and caught in aluminum absorbers of varying thickness from about 10 μg/${\mathrm{cm}}^2$ to about 180 μg/${\mathrm{cm}}^2$ were determined. The resulting integral recoil distribution at 396 MeV indicate that there are two groups of recoiling ${\mathrm{Cu}}^{64}$ nuclei. The short-range group has a maximum range of about (45±5) μg/${\mathrm{cm}}^2$ of aluminum, and the long-range group has a maximum range of about (180±8) μg/${\mathrm{cm}}^2$ of aluminum. At 130 MeV only one recoil range was observed, which has a maximum range of about (50±5) μg/${\mathrm{cm}}^2$ of aluminum. The angular distribution of the recoiling ${\mathrm{Cu}}^{64}$ nuclei was also determined using a 10-μg/${\mathrm{cm}}^2$ copper target and thick aluminum catcher foils. The short-range ${\mathrm{Cu}}^{64}$ recoils were interpreted in terms of an inelastic ($p,p^{\prime }$) scattering mechanism followed by neutron evaporation. The long-range recoils can be interpreted in terms of the knock-out mechanism. The relative number of events taking place by these two mechanisms is about equal. Reasonable agreement is obtained between predictions based on the two mechanisms and the experimental observations.