Fusion suppression in mass-asymmetric reactions leading to Ra compound nuclei -: art. no. 014603

Near-barrier excitation functions have been measured for evaporation-residue production and fission in the C-12+Pb-204,Pb-206,Pb-208 and Ca-48+Er-168,Er-170 systems that lead to the compound nuclei Ra-216,Ra-218,Ra-220*. A pronounced suppression of evaporation-residue production is observed for the more symmetric combinations, Ca-48+Er-168,Er-170. We relate this to the significant quasifission components already observed for these systems.