The Calculations Of Heavy Nuclear Fission Rate With Test Coupling Particles Multi-Passing Over Saddle Model

The thesis mainly studies the heavy nuclear fission, the problem of passing-over thermal potential is properly described by coupling test particles multi-passing over saddle model and study the effects of anharmonic potential to nuclear fission rate. Using langevin numerical simulation and comparing with the previous experimental results of a single particle. We can get a lot of reasonable and meaningful conclusions.Resent years, Langevin equation is used widely in the explanation of compound nuclear fission rate, the rate defined to the saddle point of nuclear fission is bigger than that defined to the breakpoint, so in the numerical simulation, some authors choose breakpoint as the basis of nuclear fission occurred. But saddle point is a very important physical concepts in nuclear fission, it is widely used in many areas of physics, the distance between Barrier vertex and the breakpoint may also affect some special physical quantities. Therefore, the rate defined in the saddle point is necessary in the study of nuclear fission. Because the experimental particle may return to the saddle point again after throughing the saddle point, experimental particle has a certain return risk, there is a backflow phenomenon. As the temperature increases, the backflow phenomenon is more obvious. So in order to track the trajectories of particles more accurately and a more reasonable calculation result, the test particle multi-passing over saddle point is proposed to study the fission mechanism.In the past work, thermal nuclear fission is simulated by one test particle multi-passing over saddle model, while the real fission process is more complicated. There are many impacts. In order to think over the influence of nuclear deformation, the coupling test particles multipassing over saddle point is proposed to study the fission mechanism. Expected by considering more factors impacts, the more suitable fission rate is calculated, we found that the model of test coupling particles multi-passing over saddle has a great influence on the rate of nuclear fission. By calculating the results, we found that in the same condition, the fission rate with the coupling experimental particles repeatedly through the barrier is bigger than the single particle.Considering the particle backflow phenomenon and the influence of the dynamics process to the steady flow that we set up in the process of fission, with the method of the test coupling particles multi-passing over saddle model, we have to modify fission barrier to study nuclear fission rate in the anharmonic fission barrier. They are steep potential, slow potential andshoulder potential. By comparing calculations, we found that they have great influence on the rate of nuclear fission.