SURVEYING THE NUCLEAR CALORIC CURVE

The 4 pi array INDRA was used to detect nearly all charged products em itted in Ar + Ni collisions between 52 and 95 MeV/u. The charge, mass and excitation energy E of the quasi-projectiles have been reconstruc ted event by event. Excitation energies up to 25 MeV per nucleon are r eached. Apparent temperatures obtained from several double isotopic yi eld ratios Tr(0) show different dependences upon E. T-6Li7Li-3He alph a(0) yields the highest values, as well as the high energy slopes Ts o f the kinetic energy spectra. Two statistical models, sequential evapo ration and gas in complete equilibrium, taking into account side feedi ng and discrete excited states population, show that the data can be e xplained by a steady increase of the initial temperature with excitati on energy without evidence for a liquid-gas phase transition.