Unexpected results in neutron-rich radioactive beams induced fusion

The fission-fragment beams at HRIBF provide a unique opportunity for studying the mechanisms of fusion involving nuclei with large neutron excess. To explore the role of transfer couplings, fusion excitation functions have been measured using neutron-rich radioactive 132Sn beams incident on 40Ca and 58Ni targets. The sub-barrier fusion enhancement for 132 Sn+40Ca is larger than that for 132Sn+58Ni although the neutron transfer Q-values are similar for the two reactions. The fusion excitation function for 46Ti+124Sn has been measured in an attempt to resolve the differences observed in 132Sn+40Ca and 132Sn+58Ni.