Recoil Behavior of theCu65(p, pn)Cu64Reaction

The recoil behavior of the ${\mathrm{Cu}}^{65}(p, pn){\mathrm{Cu}}^{64}$ reaction has been measured at bombarding energies from 100 Mev to 400 Mev by performing radiochemical integral recoil experiments. The fraction of the total ${\mathrm{Cu}}^{64}$ produced, found in the forward, backward, and right angle directions, shows definite structure with increasing bombarding energy. The data can be qualitatively interpreted by assuming the two-step cascade-evaporation mechanism to be relatively more important at low incident energies and a knock-on mechanism to be relatively more important at the higher incident energies. By means of a postulated velocity vector diagram, the average recoil range as a function of incident energy was calculated, and this calculated range was then converted to ${\mathrm{Cu}}^{64}$ kinetic energy by an experimentally determined range-energy relationship. The ${\mathrm{Cu}}^{64}$ was found to have an average kinetic energy of 380 kev at 105 Mev incident energy, to decrease to 105 kev at about 200 Mev, and then to increase to 195 kev at 400 Mev. This behavior is interpreted in terms of the cascade-evaporation mechanism and the knock-on mechanism.