COMPLEX FRAGMENT PRODUCTION IN KR-INDUCED REACTIONS AT INTERMEDIATE ENERGIES

Several features of complex fragment production at intermediate energies can be understood from the coupling of a dynamical description, which takes into account entrance-channel properties, and a statistical decay of equilibrated primary sources. We discuss this point using two different models for the dynamics, both based on the idea of the competition between mean field and two-body effects in this intermediate-energy range. The importance of a slow emission of large clusters in the de-excitation stage is stressed, with the possibility of using a suitably extended evaporation code. Fragment yields and spectra are analysed for Kr-induced reactions on C, Al, Ti at 34.4 MeV/A and on Au at 43 MeV/A. The effects of a different equation of state (e.o.s.) used in microscopic calculations is analysed. A stiffer e.o.s. implies more stopping of the fragments. Finally, projectile-like fragments produced in the Kr + Au reaction at 200 MeV/A are analysed. The predictions of the participant-spectator model are confirmed in this energy range.