Study On The Residual Cross Section Of Super-heavy Nuclei Under The Framework Of DNS Model

Mechanism of the synthesis of Super Heavy Nuclei?SHN?is one of the hot topics in nuclear physics recently.In this thesis,the evaporative residual?ER?cross sections of SHN have been studied with di-nuclear system?DNS?model.The thesis will be divided into three parts.Part 1:Firstly,the capture cross sections for several incident channels are numerically calculated.Then,the result of calculated driving potentials shows the premise of fusion is to overcome the inner fusion barrier for DNS.The fusion probability of compound nucleus is calculated by solving Master's equation.And the survival probability is also studied.Finally,the ER cross sections for several incident channels are obtained.Part 2:Mechanism of the synthesis of SHN in heavy-ion collisions is studied with DNS model.The inner fusion barrier is of vital importance for the fusion probability.It is shown that when the inner fusion barrier is zero,the fusion probability of compound nucleus is nearly 1.For the reactions with isotopes as projectiles,driving potential is more important than deexcitation process for the maximum ER cross sections.However,for the reactions with isotopes as targets,deexcitation process is much more important than driving potential.Part 3:Symmetric and nearly symmetric collisions are studied with DNS model.The driving potential and ER cross sections of ¹⁵⁴ Sm+¹5454 Sm,¹5050 Nd+¹5050 Sm and ¹⁵⁴ Sm+¹6060 Gd have been estimated.The ER cross sections of ⁵⁰Ti+²⁴⁹Cf is also obtained.It is found that the difference in the mass asymmetry of incident channel will lead to the great difference in the ER cross section.In addition,the ER cross sections of ⁹⁶Sr+²⁰⁹Po and ¹³²Sn+¹⁷⁸Hf are also calculated.