Angular Distributions of Protons from the Reaction 12 C(α, p ) 15 N

Angular distributions of protons corresponding to the ground state transition from the reaction 12 C(α, p ) 15 N have been measured at twelve energies of alpha particles between 25 and 39 MeV. Each angular distribution shows pronounced diffraction-like patterns, but there exists apparently a systematic shift in the shape and magnitude of angular distributions as the energy changes. At lower energies a sharp rise in the backward angles is observed, while at higher energies it is not observed. Angular distributions of protons corresponding to some excited state transitions have also been measured at 34.6 MeV.