Influence of projectile α-breakup threshold on complete fusion

Complete fusion excitation functions for B-11,B-10 + Tb-159 have been measured at energies around the respective Coulomb barriers, and the existing complete fusion measurements for Li-7 + Tb-159 have been extended to higher energies. The measurements show significant reduction of complete fusion cross sections at above-barrier energies for both the reactions, B-10 + Tb-159 and Li-7 + Tb-159, when compared to those for B-11 + Tb-159. The comparison shows that the extent of suppression of complete fusion cross sections is correlated with the a-separation energies of the projectiles. Also, the two reactions, B-10 + Tb-159 and Li-7 + Tb-159 were found to produce incomplete fusion products at energies near the respective Coulomb barriers, with the a-particle emitting channel being the favoured incomplete fusion process in both the cases. (C) 2006 Elsevier B.V. All rights reserved.