Seminarium Fizyki Jądra Atomowego

A new rapidly convergent shape parametrization based on the Fourier expansion is proposed to model the fission of heavy nuclei. Four collective coordinates are used to characterize the shape of the fissioning system: its elongation, left-right asymmetry, neck size, and nonaxiality. The potential energy landscape is computed within the macroscopic-microscopic approach, on top of which the multi-dimensional Langevin equation is solved to describe the dynamics. The charge equilibration at the scission configuration and the neutron evaporation from the primary fragments after scission is considered. The model gives access to various observables, including fission fragments’ mass, charge, kinetic energy yields, fragment mean N/Z and post-scission neutron multiplicities. The parameters of the model were tuned to reproduce experimental observation from thermal neutron-induced fission of 235U and next used to discuss the transition from the asymmetric to symmetric fission along the Fm isotopic chain as well as to describe the fragment yields produced in fission of excited 250Cf nucleus.