Differential Cross Sections of Some (α, p) Reactions

Using 30.4-Mev alpha particles, proton differential cross sections were obtained for the following transitions, corresponding to discrete states of the residual nuclei: B/sup 10/( alpha ,p)C/sup 13/ ground-state; Na/sup 23/ ( alpha ,p)Mg/sup 26/ ground- and Mev-states; Al/sup 27/ ( alpha ,p)Si/sup 30/, ground- and 2.24-Mev states; and P/sup 31/( alpha ,p)S/sup 34/, ground-state. A proton energy spectrum corresponding to the first 12 Mev of excitation of the residual nucleus was obtained for the case involving the Al/sup 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 calcalculations are discussed. (auth)