Four-dimensional Langevin approach to fission with Cassini shape parameterization

Abstract

We apply the Cassini shape parameterization to the dynamical study of actinide fission using the multi-dimensional Langevin equation. The fragment mass distributions for fission of 236U and 256, 258 Fm are calculated with the 4D Langevin equation. The 4D collective space is formed by adding either α3 or α6 to the basic 3D {α, α1, α4} space. We investigate the role of α3 and α6 by comparing the results of 4D (α3 or α6) with that of 3D. For 236U and 256Fm, where asymmetric fission is predominant, the fragment mass distributions calculated in the 4D (α3) space are in good agreement with experimental data. On the other hand, for 258Fm, which is characterized by symmetric fission, 4D (α6) is effective for describing the shape of compact symmetric fragments. We demonstrate the advantages of the Cassini shape parameterization for the dynamical study of actinide fission.