Mass dependence of the fusion of Ni + Sn

Preliminary results are presented for a comprehensive study of the fusion of Ni 64 and Ni 58 on Sn 112-124 for the energy range 150-200 MeV in the center of mass. Cross sections were measured for evaporation residues and for fission. Evaporation cross sections are a function of neutron excess while fission cross sections are not, a manifestation of compound-nucleus formation processes. Both evaporation residue and fission cross sections are enhanced at low energies