STUDY OF THE VIOLENT COLLISIONS BETWEEN CU-63-232 AT 35 MEV(TH)NUCLEON/

A study of the decay of hot and heavy composite nuclei produced in the violent collisions between Cu-63 and Th-232 at 35A MeV is presented. The measurement of fission fragment correlations indicates that simila r to 70% of the projectile linear momentum can be transferred to the f issioning system. Heavy reaction products were observed at a laborator y angle of theta=6 degrees in coincidence with neutrons, Light charged particles, and intermediate mass fragments. The dynamical aspects of the collisions between the projectile and target nuclei were investiga ted using the computer code CHIMERA which is based upon the molecular dynamics concept. Asymptotic characteristics of the reaction products were confronted with results of calculations of the tandem CHIMERA plu s GEMINI codes. The data and model comparisons show that a composite s ystem of mass as high as 275 amu and with an excitation energy similar to 1 GeV is formed in the most violent collisions. Some of the heavy reaction remnants are located on the fragment mass versus velocity pla ne inside the area whew the evaporation residues resulting from the de cay of the hot composite system are expected. A high neutron multiplic ity associated with these events indicates their origin in the most di ssipative events. However, a low cross section for the production of t hese remnants and the close similarity of their characteristics to the fission fragments do not allow more conclusive statements.