Differential Range Study of Products Formed by 2.9-GeV Proton Irradiation of Silver

Abstract

Thin silver targets (≈0.1 mg/${\mathrm{cm}}^2$) were irradiated with 2.9-GeV protons. The recoiling products were collected in a stack of thin plastic films at 90° to the beam, at a geometry of 2%. By radiochemical separation ${\mathrm{Sr}}^{83}$, ${\mathrm{Cu}}^{61,64}$, ${\mathrm{Sc}}^{43,44}$, ${\mathrm{K}}^{42,43}$, and ${\mathrm{Na}}^{24}$ were removed from the films. Range distributions were obtained for each, and from these the corresponding energy spectra and velocity spectra were deduced. The mean energies are: ${\mathrm{Sr}}^{83}$—3.2 MeV, ${\mathrm{Cu}}^{61-64}$—5.9 MeV, ${\mathrm{Sc}}^{43,44}$—9.4 MeV, ${\mathrm{Na}}^{24}$—18.1 MeV. Comparison of the observed spectra with the results of Monte Carlo cascade-evaporation calculations showed excellent agreement for all of the products except ${\mathrm{Na}}^{24}$. It is concluded that the former are mainly spallation residues while ${\mathrm{Na}}^{24}$ is formed by the splitting of a parent nucleus into two fragments. All of the energy spectra are very broad and there is no sharp difference between "spallation-type" spectra and "two-body breakup" type spectra.