Differential Range Study ofNa24Formed by 2.9-GeV Proton Irradiation of Light Elements

Abstract

Thin targets (≈50 μg/${\mathrm{cm}}^2$) of copper, vanadium, and chlorine (Saran) were irradiated with 2.9-GeV protons. Products recoiling at 90° to the beam were collected in a stack of thin plastic films, at a geometry of 2%. The range distributions of ${\mathrm{Na}}^{24}$ were determined by radiochemical separation, and energy spectra were deduced from the measurements. The mean energies of ${\mathrm{Na}}^{24}$ from copper, vanadium, and chlorine are 8.2, 6.1, and 4.3 MeV, respectively. The observed energy spectra were compared with the results of Monte Carlo cascade-evaporation calculations, and very good agreement was obtained for copper and vanadium. The calculation predicts significantly larger recoil energies than observed in the case of the chlorine target. It is concluded that this is due to an overestimate of the transverse component of momentum imparted to the residual nuclei ln the cascade process.