Hot nuclei studied with a 4 π-neutron detector

The challenge in understanding the behavior of hot nuclei is twofold: how are they formed in nucleus-nucleus collisions and how do they decay? Systematic studies have been undertaken at GANIL by bombarding heavy targets (Au + Th) with intermediate energy medium mass projectiles (27, 35, 44, 77 MeV/u Ar and 32 MeV/u Kr). For such neutron rich systems the dissipated energy can be essentially evaluated by measuring the multiplicity of evaporated neutrons using a 4π, Gd loaded scintillator detector. Several exit channels (binary fission, evaporated light charged particles and intermediate mass fragments) have been investigated as a function of the entrance channel parameters (essentially the mass and velocity of the projectile)