Reaction-dependent spin population and evidence of breakup in O18

Angular distributions and angular correlations have been measured for the emission of one and two alpha-particles in the O-18+Pb-207,Pb-208,Bi-209 reactions at several beam energies above the Coulomb barrier. The results rule out fusion evaporation as the main reaction mechanism for the channels involving alpha-particle emission and support the interpretation of the breakup of the O-18 projectiles into at least C-14+alpha and Be-10+Be-8 before fusion.