Influence of neutron enrichment on compound system formation and decay in 78Kr+40Caand 86Kr+48Careactions at 10 AMeV

The de-excitation of medium mass nuclei Ba-118,Ba-134 produced in fusion process of Kr-78,Kr-86 on Ca-40,Ca-48 targets at 10 AMeV is studied, in order to investigate the isospin dependence of the decay modes; the neutron enrichment of the compound nuclei is in fact expected to play an important role on the emission mechanisms, providing crucial information on fundamental nuclear quantities such as level density, fission barrier, viscosity and symmetry energy. The experiment was performed at INFN-LNS with the 4 pi multidetector for charged particles CHIMERA, used for the first time in this low energy regime, thanks to a suitable Pulse Shape Discrimination method for charge identification applied to the silicon detectors. Preliminary results show a different isotopic composition and relative enrichment for the same Z in the two systems. The yields of the Intermediate Mass Fragments (IMF, 3更多