Computer Simulation of Temperature Measurements in Heavy-Ion Collisions

The observed differences in kinetic and chemical temperatures in heavy-ion reactions is addressed by means of a computer simulation. Focusing on ⁴He nuclei emitted at wide angles, we find that the chemical temperatures show no strong variation with laboratory bombarding energy between 35 and 100 MeV/nucleon. Further, the chemical temperature is found to be in the 3---4-MeV range, much lower than the kinetic temperature and consistent with experiment. The difference in the two temperatures is established after a fairly short time scale roughly corresponding to the breakup time of the reaction region.