Search for a Phase Transition in Nuclear Matter for Temperatures up to 7 MeV

Abstract

The study of hot and heavy nuclei with temperatures between about 5 and 7 MeV presents an unquestionable interest: Hartree-Fock¹ calculations as well as Thomas-Fermi² calculations predict a limit in the temperature that a heavy nucleus (A-150) could sustain within this range. A liquid-gas phase transition for hot nuclear matter could also occur within this temperature range. The idea of a phase transition in nuclear matter arose initially from the van der Waals-like behavior of the nuclear force³. Recently, a caloric curve, built with a temperature scale derived from the yield ratios of He and Li isotopes, has been reported⁴ and exhibits the characteristic shape expected for such a transition with a plateau at a constant temperature T = 5 MeV for excitation energies per nucleon between about 2.5 and 10 MeV. In the present contribution, a signature of such a phase transition is searched for (but not found) in the energy spectra of the light charged particles emitted by strongly heated nuclear matter.