High-energy fission and the onset of quasi-fission

Abstract

This thesis delves into nuclear fission, a complex process discovered in 1939, exploring extreme deformations, nuclear structure effects, and heat flows influencing fragment distributions. The study focuses on fusion-induced fission in 265Db and 249Bk fissioning systems generated with high excitation energies employing inverse kinematics with the VAMOS++ spectrometer. Asymmetric fission channels are observed, providing insights into nuclear charge, mass, neutron excess, and neutron evaporation. In the case of 265Db, an overproduction of heavy fragments attributed to quasi-fission is observed. For 249Bk, the characterization of the scission point is studied through crucial indirect observables for understanding nuclear structure effects, such as the total kinetic energy averaged before neutron evaporation.