Dependence of intermediate mass fragment production on the reaction mechanism in light heavy-ion collisions at intermediate energy

The same hot nuclear system (Sigma Z=18) has been studied for two different entrance channels with reaction products detected in a forward array of scintillators: central collisions of Mg-24 on a C-12 target at 25A and 35A MeV and peripheral pickup reactions of Cl-35 on a Au-197 target at 43A MeV. The detection-efficiency-corrected charge distributions, multiplicity of charged particles and cross sections as a function of excitation energy are compared. The reaction mechanism is investigated, through comparison to simulations with statistical observables. The central reaction Mg-24+C-12 at 35A MeV is well characterized by a dissipative binary collision scenario. Data at 25A MeV show less evidence of such dynamical characteristics. The intermediate-mass fragments (3 less than or equal to Z less than or equal to 8) production for each reaction is compared to model calculations for different values of excitation energy. The systems formed in the central collision at 25A MeV and the pickup reaction at 43A MeV show similar source characteristics, both statistically and in momentum space. However, the yields of the various exit channels, from evaporation and/or fission to multifragmentation and vaporization, differ for the two reactions.