Dynamical approach to heavy-ion induced fission using actinide target nuclei at energies around the Coulomb barrier

Aritomo, Yoshihiro; Hagino, Koichi*; Nishio, Katsuhisa   ; Chiba, Satoshi

In order to describe heavy-ion fusion reactions around the Coulomb barrier with an actinide target nucleus, we propose a model which combines the coupled-channels approach and a fluctuation-dissipation model for dynamical calculations. Fusion-fission, quasi-fission and deep quasi-fission are separated as different Langevin trajectories on the potential energy surface. Using this model, we analyze the experimental data for the mass distribution of fission fragments (MDFF) in the reactions of S+U and Si+U at several incident energies around the Coulomb barrier. We find that the time scale in the quasi-fission as well as the deformation of fission fragments at the scission point are different between the Si+U and S+U systems, causing different mass asymmetries of the quasi-fission.