Using 30.4-Mev alpha particles, proton differential cross sections have been obtained for the following transitions, corresponding to discrete states of the residual nuclei: ${\mathrm{B}}^{10}(\alpha , p){{\mathrm{C}}^{13}}_{\mathrm{gnd}}$; ${\mathrm{Na}}^{23}(\alpha , p){{\mathrm{Mg}}^{26}}_{\mathrm{gnd},1.83\mathrm{}\mathrm{Mev}}$; ${\mathrm{Al}}^{27}(\alpha , p){{\mathrm{Si}}^{30}}_{\mathrm{gnd},2.24\mathrm{}\mathrm{Mev}}$; and ${\mathrm{P}}^{31}(\alpha , p){{\mathrm{S}}^{34}}_{\mathrm{gnd}}$. A proton energy spectrum corresponding to the first 12 Mev of excitation of the residual nucleus was obtained for the case involving the ${\mathrm{Al}}^{27}$ target. The differential cross sections are interpreted with the aid of predictions of the Butler direct-interaction (surface) theory. It is concluded that this theory is probably a more useful tool in interpreting the results obtained than is the compound nucleus theory. Some deviations from the predictions of the surface direct-interaction calculations are discussed.

• Received 16 February 1959

DOI:https://doi.org/10.1103/PhysRev.115.956