EMISSION TEMPERATURES OF HOT NUCLEI FROM-POPULATIONS OF PARTICLE UNSTABLE STATES AS A FUNCTION OF IMPACT PARAMETER

The α-α correlation at small relative angles has been measured for ４０ Ar-induced reactions on 197 Au at E/A=25MeV, in coincidence with two fission fragments. The relative populations of states of 8 Be and emission temperature of hot nuclei are extracted from the α-α correlation function. The emission temperature changes slightly with the impact parameter, from about 4MeV for central collision to about 3.8MeV for peripheral collision. At peripheral collision, the emission temperature is observed to increase with the energy of particles.