Analysis of dynamical processes using the mass distribution of fission fragments in heavy-ion reactions

We analyze experimental data obtained for the mass distribution of fission fragments in the reactions S-36+U-238 and Si-30+U-238 at several incident energies, which were performed by the Japan Atomic Energy Agency (JAEA) group. The analysis of the mass distribution of fission fragments is a powerful tool for understanding the mechanism of the reaction in the heavy and superheavy-mass regions. Using the dynamical model with the Langevin equation, we precisely investigate the incident energy dependence of the mass distribution of fission fragments. This study is the first attempt to treat such experimental data systematically. We also consider the fine structures in the mass distribution of fission fragments caused by the nuclear structure at a low incident energy. It is explained why the mass distribution of fission fragments has different features in the two reactions. The fusion cross sections are also estimated.