(p,Be7) Reaction in Al and Mg from 27 to 31.5 MeV

A study has been made of the cross sections for the ${\mathrm{Al}}^{27}(p, {\mathrm{Be}}^7)$ and the $\mathrm{Mg}(p, {\mathrm{Be}}^7)$ reactions in the energy range 27 to 31.5 MeV. The ${\mathrm{Al}}^{27}(p, {\mathrm{Be}}^7)$ data are contrasted with the known ${\mathrm{Mg}}^{24}$(${\mathrm{He}}^4$,${\mathrm{Be}}^7$) reaction cross sections using 30- to 42-MeV He ions, both of which lead to the same compound nucleus. It is seen that the reactions proceed chiefly by a compound nuclear mechanism in this energy range. A three-nucleon transfer direct-interaction mechanism is a possible contributor to the He-ion-induced reaction.