Shell effects in fission and quasi-fission

¹ Department of Fundamental and Theoretical Physics, and Department of Nuclear Physics and Accelerator Applications, Research School of Physics, Australian National University, Canberra ACT 2600, Australia
² CEA, DES, Cadarache, F-13108 Saint Paul les Durance, France
³ CEA, DAM, DIF, F-91297 Arpajon, France
⁴ Université Paris-Saclay, CEA, Laboratoire Matière sous Conditions Extrêmes, 91680 Bruyères-Le-Châtel, France
⁵ Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
⁶ Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA

^* e-mail: cedric.simenel@anu.edu.au

Published online: 18 October 2024

Abstract

Quantum shell effects are responsible for asymmetric fission. They are also expected to affect the formation of fission fragments in quasi-fission reactions occurring in heavy-ion collisions. Shell effects in fission are studied with the single-particle energy level density near the Fermi level. In particular, shell effects in the pre-fragments and their role in fixing the final mass asymmetry of the fission fragments are discussed. Systematic time-dependent Hartree-Fock simulations of heavy-ion collisions show that quasi-fission fragment properties share strong similarities with fragments formed in fission of the compound nuclei. This is an indication that similar shell effects are responsible for the final asymmtery in both mechanisms.