Measurement and analysis of. cap alpha. particles emitted in reactions of /sup 12/C bombarding /sup 12/C, /sup 27/Al, and /sup nat/Ca

The energy spectra and angular distributions of the ..cap alpha.. particles emitted in the reactions of 69.5 MeV /sup 12/C bombarding /sup 12/C, /sup 27/Al, and /sup nat/Ca have been measured and analyzed using the fast-particle exciton model. The contribution from the equilibrium and pre-equilibrium ..cap alpha.. emissions is calculated to be 89%, 81%, and 83% of the total ..cap alpha.. yields for the three reactions, respectively, where the pre-equilibrium ..cap alpha.. emissions are 11%, 14%, and 16%, respectively. A small contribution comes from other reaction mechanisms.