Recoil Ranges of Products from Reactions of Copper with 11—43-MeVHe4Ions

Average projected ranges have been determined for the following reactions of copper with 11—43-MeV ${\mathrm{He}}^4$ ions: ${\mathrm{Cu}}^{65}(\alpha , n)$, ${\mathrm{Cu}}^{65}(\alpha , 2n)$, ${\mathrm{Cu}}^{65}(\alpha , 3n)$, ${\mathrm{Cu}}^{65}(\alpha , \alpha n)$, and ${\mathrm{Cu}}^{63}(\alpha , n)$. The results have been compared with calculations based on the assumption of compound-nucleus formation. Good agreement has been obtained at all energies for the ($\alpha , \mathrm{xn}$) reactions. On the other hand, the ranges of ${\mathrm{Cu}}^{64}$ are considerably smaller than those predicted by the theory, indicating that there is a significant contribution of a direct process to the ($\alpha , \alpha n$) reaction.