Observation of a saturation in the time scale for multifragment emission in symmetric heavy-ion collisions

Abstract

We have measured two-fragment reduced-velocity correlation functions of the intermediate mass fragments (IMF: 3\ensuremath{\le}Z\ensuremath{\le}7) produced in multifragment final states for the Kr+Nb system (E/A=35, 45, 55, 65, and 75 MeV). From the measured correlation functions we extract mean IMF emission lifetimes (\ensuremath{\tau}) which are observed to decrease from \ensuremath{\tau}\ensuremath{\approxeq}400 fm/c at E/A=35 MeV to \ensuremath{\tau}\ensuremath{\approxeq}125 fm/c at E/A=55 MeV. For beam energies in excess of E/A=55 MeV, no further decrease in \ensuremath{\tau} is observed, indicating a possible saturation of the mean emission lifetime for IMF produced in multifragment exit channels.