Sub-barrier resonance fission and its effects on fission fragment properties, exemplified on ^234,238U(n,f)

A. Tudora¹, F.-J. Hambsch² and S. Oberstedt²

¹ University of Bucharest, Faculty of Physics, Bucharest-Magurele, RO – 77125, Romania
² EC-JRC-Institute for Reference Materials and Measurements (IRMM), 2440 Geel, Belgium

Abstract

The correlation between the sub-barrier resonant behaviour of fission crosssection of non-fissile actinides (pre-scission stage) and the visible fluctuations of their fission fragment and prompt neutron data (post-scission stage) around the incident energies of sub-barrier resonances is outlined and supported by quantitative results for two fissioning systems ^234,238U(n,f). These quantitative results refer to both stages of the fission process: a) The pre-scission stage including the calculation of neutron induced cross-sections with focus on fission. Calculations are done in the frame of the refined statistical model for fission with sub-barrier effects also extended to take into account the multi-modal fission. b) The post-scission stage including the prompt neutron emission treated in the frame of the Point-by-Point model. Total quantities characterizing the fission fragments and the prompt neutrons obtained by averaging the Point-by-Point results as a function of fragment over the fission fragment distributions reveal variations around the energies of sub-barrier resonances in the fission crosssection.