Study of neutron induced fission of actinides in a macroscopic-microscopic model

Abstract

The macroscopic-microscopic (MM) model, as a powerful theoretical tool for the understanding of nuclear fission mechanism, is deemed to be a so impressive theoretical method that its calculated results would quantitatively predict the fission observables in the near future. This paper reviews our recent progress in the theoretical calculations of the five-dimensional (5D) potential energy surfaces (PESs) and the fission fragment mass distributions for the neutron induced fission of actinides within the framework of the MM model along with the random walking method and Langevin model. Firstly, we use the 5D generalized Lawrence shape and three quadrature surfaces parameterizations as the shape descriptions, the Lublin-Strasbourg Drop model for the macroscopic energy and the folded-Yukawa model as the single-particle potential. A new method to use a two-center oscillator basis in calculating Hamiltonian matrix on any kind of shape description is presented. Then, the advanced search algorithms are developed and used in searching for the optimal fission path, fission saddles and other structure information on a 5D PES surface. The method of random walks on 5D PESs is used to calculate the fission fragment mass distributions for the 235U(n,f) reaction. Finally, three-dimensional Langevin model with a constraint on the heavy fragment deformation are applied to study the fragment mass distributions for 14 MeV neutron-introduced fissions of uranium isotopes.