Collisions between 48 Ti 1 93 Nb at 917 MeV

One of the most striking findings in the early days of low-energy, heavy-ion nuclear physics was the observation of deep inelastic collisions ~DIC! @1#. These reactions can make up a substantial fraction of the total reaction cross section and are characterized by the conversion of a large amount of the relative kinetic energy into internal excitations of the colliding nuclei without obliterating the identity of the projectile and target. With increasing bombarding energy, the reaction picture becomes considerably more complex. New phenomena, such as preequilibrium emission @2#, intermediate mass fragment ~IMF! emission @3#, and projectile breakup @4# enter the reaction process. However, the recent experiment on intermediate-energy, heavy-ion reactions by Lott et al. @5# indicates that the collisions of Xe 1 Bi at 28.2 MeV/nucleon are predominantly of a binary nature leading to highly excited massive primary projectilelike ~PLF! and targetlike fragments ~TLF!. Surprisingly, this binary character persists for collisions at 45 MeV/nucleon @6# even when a large number of the IMF’s are observed. The binary dissipative processes were observed recently at energies approaching 100 MeV/nucleon @7# and at 29 MeV/nucleon in collisions of very heavy nuclei @8#. The important characteristics of these strongly damped reactions are the partition of the mass, charge, excitation energy, and angular momentum between the PLF’s and TLF’s. Despite the obvious importance of the DIC process, a complete under-