Energy dependence of the fragmentation of the Au projectile in Au-emulsioninteractions

The fragmentation of gold nuclei interacting in nuclear emulsions is studie d over the energy range of 0.1 to 10.6 GeV/nucleon. Different fragmentation processes are selected and investigated. The probability of fission of the gold nucleus strongly decreases with increasing beam energy. On the other hand, spallation processes do not show a significant energy dependence. At low incident energies nuclear multifragmentation only occurs in rather cent ral Au-Emulsion interactions, while at 10.6 GeV/nucleon it is also observed in more peripheral collisions. The statistical properties of the multifrag mentation events are studied. It is found that the mechanism responsible fo r gold multifragmentation is different than for other fragmentation process es, although no evidence suggesting the presence of a liquid-gas phase tran sition is found. Among Au-Emulsion interactions at 10.6 GeV/nucleon we also observe a small fraction of events in which the projectile gold nucleus is completely broken into singly charged fragments. Such events are not seen at lower energies. These interactions are the most central collisions and a re accompanied by a considerable production of secondary particles.