Rapid Decrease of Fragment Emission Time in the Range of 3-5 Mev/u Excitation-energy

Multifragment emission processes from highly excited nuclei produced in Ar-40+Au-197 reactions at incident energies of 30 and 60 MeV/u are compared. At the lowest bombarding energy and 3.3 MeV/u excitation energy, the composite system decay process supports the hypothesis of long-lived equilibrated nuclei decaying by successive binary splittings. For excited nuclei around 5 MeV/u, the depletion observed at small relative angles in the correlation functions is interpreted as the result of a strong reduction in the fragment emission time scale.