Ternary and quaternary re-separation of heavy colliding systems

Abstract

Collisions of two very heavy nuclei, 197Au + 197Au, were studied at a beam energy of 15 MeV/nucleon. Such a heavy system cannot fuse and form a compound nucleus. Therefore main re-separation modes of the colliding system can be studied in a wide range of impact parameters: in near-central as well as semi-peripheral collisions. The experiment was carried out at the Laboratori Nazionali del Sud in Catania. The 197Au beam was accelerated to the energy of 15 MeV/nucleon with the LNS Super-Conducting Cyclotron and bombarded a 273 mg/cm2 - thick 197Au target, placed inside the Charge Heavy Ion Mass and Energy Resolving Array (CHIMERA). A new reaction mechanism of fast collinear ternary and quaternary fast breakup processes has been observed. Results show that these ternary and quaternary reactions occur at extremely deep-inelastic collisions corresponding to small values of the impact parameter.