Decay of¹⁶⁰ Er* in¹⁶ 0 +¹⁴⁴ Nd and⁶⁴Ni +⁹⁶Zr Fusion Reactions

The population of evaporation residue entry states in the decay of the compound nucleus¹⁶⁰Er*(54 MeV) is investigated in a cross-bombardment employing the re actions 160 + 144Nd and⁶⁴Ni +⁹⁶Zr. Evaporation residue cross sections and entry state γ -ray fold distributions of the dominant exit channels were obtained for each reaction, using a 4π γ -ray detection system. An entrance-channel dependence of the γ-ray fold distributions of the xn products is observed. This effect is described successfully by the statistical model making use of compound nucleus angular mo mentum distributions obtained with a fusion model that provides a good description of the bombarding energy dependence of fusion data for both reactions. In accor dance with recent findings on the decay of 164Yb*, it is suggested that the observed differences in the population of the dominant exit channels originate from the pri mary spin distributions rather than a possible dependence of the compound nucleus decay on the formation mode.