A study of 197Au+197Au collisions at 15 MeV/nucleon with the CHIMERA multidetector

Following theoretical predictions regarding dynamics of very heavy systems, 197Au + 197Au collisions at an energy of 15 MeV/Nucleon were studied in order to observe a transition from one-body dissipation mechanism that dominates for cold nuclear matter to two-body dissipation. The experiment was carried out in 4pi geometry using the CHIMERA multi-detector array. A class of ternary events satisfying nearly complete balance of mass numbers and balance of the transversal momentum was selected. Preliminary results show that ternary partitions of the heavy Au + Au system predominantly lead to formation of three fragments of comparable masses. In the light of theoretical predictions of Carjan, Sierk and Nix this result implies tha t the observed ternary reactions are driven by the two-body dissipation mechanism already at 15 MeV/ nucleon.