Multifragment events in the reaction 58Ni+27Al at 15.8 MeV/nucleon.

Abstract

Intermediate mass fragment (IMF) production was studied in the inverse kinematics reaction [sup 58]Ni+[sup 27]Al at 15.8 MeV/nucleon bombarding energy using the Heavy Ion Light Ion (HILI) detector. Exit channels with up to 4 IMFs have been observed. The three-body events can be ascribed to different production mechanisms: (i) incomplete momentum transfer with projectile spectator breakup, (ii) sequential fission following a deep inelastic reaction, and (iii) fast sequential fission (i.e., with Coulomb final-state interaction) in competition with a prompt breakup out of a toroidal configuration. The identified ternary reaction mechanisms, covering an extremely wide dynamic range, could be observed simultaneously; a subgroup of events is compatible with an instantaneous breakup of a highly excited nuclear system.