Selection of projectiles for producing trans-uranium nuclei in transfer reactions within the improved dinuclear system model

Abstract

The multi-nucleon transfer process is a promising approach for producing neutron-rich heavy nuclei. Its favorable projectile-target combinations play a key role in experiments. As an important theoretical approach to investigate the multi-nucleon transfer process, the dinuclear system (DNS) model is improved and shown in detail. Based on the degree of freedom of the deformation of the improved DNS model, a method of calculating the excitation energies of the primary fragments is proposed, and a remarkable improvement in describing the experimental data is noted. To produce trans-uranium nuclei, the collisions of 48Ca, 136Xe, and 238U projectiles with the 238U target are investigated within the improved DNS model. Based on the potential energy surface, the influence of the projectiles on the probabilities of transferring neutrons and protons from the projectiles to the target are studied. One behavior found is that the transfer probabilities strongly depend on the projectiles in the neutron stripping process, while a relatively weak projectile dependence is seen in the proton transferring process. The 136Xe and 238U projectiles show great advantages of cross sections for producing neutron-rich trans-uranium nuclei, although the fission probabilities are large.