Multifragmentation of very heavy nuclear systems (III): Fragment velocity correlations and event topology at freeze-out

Kinetic energy spectra and fragment velocity correlations, simulated by means of stochastic mean-field calculations, are successfully confronted with experimental data for single multifragmenting sources prepared at the same excitation energy per nucleon in 32 A MeV 129Xe + natSn and 36 A MeV 155Gd + natU central collisions. Relying thus on simulations, average freeze-out times of 200–240 fm/ c are estimated. The corresponding spatial distributions of fragments are more compact for the lighter system ( ∼ 3 – 4 V 0 vs. ∼ 8 V 0 ).