Mechanisms for reactions of α-particles on 28Si at Eα = 65 MeV leading to three-body final states

A kinematically complete measurement has been made of all charged particles produced by 65 MeV a-particles on Si. Singles, coincidence and projected energy spectra are presented. The following processes have been identified: (i) quasi-free projectile breakup; (ii) binary breakup due to the inelastic excitation of the projectile to an unbound excited state; (iii) charged particle decay of the residual nucleus following mass-transfer reactions; (iv) pickup processes to Li unbound states with the subsequent decay into a and either p, d or t; (v) coincident proton evaporation. The cross section for process (i) is at least one order of magnitude smaller than the corresponding process induced by 3He at the same beam velocity. It has been found that the selectivity for populating states in a final nucleus is almost independent of the reaction leading to that nucleus.