Asymmetry Dependence of Nuclear Temperatures and Densities

Quasi-projectile sources produced in collisions of 70Zn+70Zn, 64Zn+64Zn and 64Ni+64Ni at E/A=35MeV have been reconstructed using the charged particles and free neutrons measured in the NIMROD-ISiS 4-pi detector. Equilibrated sources were selected which have a mass A=48-52 and which are on average spherical. Caloric curves for these quasi-projectiles have been extracted with the quadrupole momentum fluctuation thermometer (QMFT) and the Albergo thermometer. The classical QMFT and the Albergo thermometer exhibit a clear dependence on the composition, (N-Z)/A, of the source. For a given excitation (E*/A), the neutron-poor sources exhibit higher temperatures. The quantum QMFT exhibits a somewhat different dependence on the composition. Since the density and temperature are correlated in the quantum QMFT, this difference may be due to a dependence of the nuclear density on the composition.