Differential Range Study of (α, xn) Reactions of Copper

The differential ranges of the ${\mathrm{Cu}}^{63}(\alpha , n)$, ${\mathrm{Cu}}^{65}(\alpha , 2n)$, and ${\mathrm{Cu}}^{65}(\alpha , 3n)$ reaction products have been measured in the energy range of 14-40 MeV by means of the electrostatic collection technique. The results have been used to derive a range-energy relation for gallium recoils in ${\mathrm{H}}_2$. Comparison with the Lindhard-Scharff-Schiott calculation indicates that the latter overestimates the importance of electronic stopping. The results have been compared with a Monte Carlo evaporation calculation and have been used to obtain the average values of the neutron and photon energies. The information obtainable from transformation of the recoil velocity distribution between the c.m. and laboratory systems has been explored. These various analyses all indicate that the differential ranges and angular distributions of the recoils yield mutually consistent results.