Studies On The Production Cross Sections Of Superheavy Nuclei Based On The Dinuclear System Model

The synthesis of superheavy nuclei (SHN) is a fast developing piece of nuclear physics. In recent years, much process has been made on both its experimental parts and theoretical ones. Until now, about 16 superheavy elements (SHE) have been synthesized in experiments except Z=117 successively, and the heaviest element is SHE 118. Small cross sections for synthesis of SHN (generally below nanobarns) and, simultaneously, short half-lives (generally below seconds) need selecting the optimal combination of target and projectile with the larger production cross sections and the most favorable bombarding energy for experiments theoretically. In this paper, within the framework of the dinuclear system model, formation probability for fusion process of SHN is obtained through solving master equation numerically with effect of the quasi-fission rate and not making any approximate to the driving potential. The effects of deformation, orientation, kinetic energy relaxation time, angular momentum relaxation and dynamics deformation relaxation time on fusion probability are studied. The results indicate that the driving potential of waist to waist is larger than that of tip to tip with the larger corresponding fusion probability whose configuration can be helpful to fusion. The dynamics deformation relaxation influences the fusion probability significantly but the angular momentum relaxation hardly affects it. The cross sections of capture and the survival probability are given by the empirical coupled channel model and the statistical evaporation model, respectively. Finally, the production cross sections of several reaction systems which can produce SHE 117 are calculated, and the results show that the hot fusion reaction systems 45Sc+ 248Cm and 48Ca + 247-249Bk can be the optimal projectile-target combinations.