Independent fission yields studied based on Langevin equation

Mass distributions of fission fragments of U and Pu isotopes at low excitation energies are studied using a dynamical model based on the fluctuation-dissipation theorem formulated as Langevin equations. Though the Langevin approaches have been applied successfully to the fission process at high excitation energy, it is the first time to obtain the mass distribution of fission fragments for the neutron-induced fission of 233,235U and 239Pu. It was found that the shell effect of the potential energy landscape has the dominant role in determining the mass distribution. The calculation results show the asymmetric fission and the good agreement with the experimental data without any parameter adjustments. Using this approach, we obtain the independent protons and neutrons fission yields of n + 233U. The present approach can serve as a basis for more refined analysis being planned in the future aiming at a realistic description of the whole process of fission, starting from the compound nuclei at various excitation energies reaching to the fission products populated after β-decay.