Nuclear temperature measurements with helium isotopes

Temperatures were determined from double isotope ratios and excited state populations and corrected for secondary decay for central Au + Au collisions at 35 AMeV. Consistent emission temperatures were obtained both from double isotope ratios and excited state populations. Center of mass energy spectra have been studied for Helium and Hydrogen isotopes emitted from highly excited residues produced in central Xe + Cu reaction at 30 AMeV. Differences between the spectra for 3He and 4He are observed that can be attributed to the time dependent evaporative cooling of hot nuclei.