Temperature measurements in Xe+Cu at 30 MeV/nucleon: Size effects in the caloric curve - art. no. 044606

Results of experiments performed to investigate the Xe+Cu 30 MeV/nucleon re action are presented. The decay products coming from the disassembly of the unique source formed in central collisions and those coming from the decay of the quasiprojectile in peripheral and midperipheral ones have been iden tified through a careful data selection taking into account the experimenta l efficiency distortion on energy and angular distributions. The nuclear te mperatures of these decaying systems have been measured from the relative i sotopic abundances; the excitation energies of the fragment sources have be en extracted by means of model calculations. The results have been compared to those obtained in the study of the Au+Au 35 MeV/nucleon in order to pro be the effects of the finite size of the intermediate mass fragment emittin g source on the relationship between its excitation energy and temperature. The studied fragment emitting sources have mass A, similar or equal to 130 , A(2)similar or equal to 200, A(3)similar or equal to 300; moreover, the A (2) system have been investigated via two different reaction channels: the quasiprojectile of peripheral Au+Au and the unique fused system of the Xe+C u central collisions. The relationship between temperature and excitation e nergy seems to be almost independent on the size of the emitting source and on the reaction entrance channel. On the contrary a weak dependence arises when individual thermometers are considered. [S0556-2813(99)03009-5].