Dynamical approach to heavy ion-induced fission

Abstract

Deep inelastic collisions (DICs) can compete strongly with fusion in collisions of heavy nuclei. However, standard coupled-channels calculations do not take DIC processes into account. As a result, calculations have been shown to overestimate the fusion cross-sections, resulting in a discrepancy between experimental data and theoretical calculations, particularly at energies above the fusion barrier. To investigate this discrepancy, we conducted a series of experiments using the ANU 14UD tandem accelerator and the CUBE 2-body fission spectrometer to examine the competition between transfer/DIC and fusion. In particular, fusion-fission and 3-body fission yields have been extracted for 34S + 232Th and 40Ca + 232Th systems. This work shows that the transfer-fission probability is enhanced relative to fusion-fission for 40Ca + 232Th, when compared to 34S+ 232Th. It is suggested that the enhancement of this DIC process in 40Ca + 232Th is linked to an increase in the density overlap of the colliding nuclei as a function of the charge product and contributes to fusion hindrance.