Speaker
Description
Angular momentum generation in nuclear fission remains one of the most intriguing and least understood aspects of the fission process. Although fission has been studied for more than eight decades, major questions persist regarding how angular momentum is generated at scission, how it is shared between the fragments and the orbital angular momentum, and how it correlates with excitation energy, deformation, and neutron emission. These questions are of central importance for our fundamental understanding of collective motion in nuclei and nuclear de-excitation processes.
In this talk, old and recent experimental and theoretical developments in the study of fission fragment angular momentum will be reviewed. Particular emphasis will be placed on modern approaches for extracting angular momentum from experimental observables. Special focus will be given to isomeric yield ratio measurements performed at the IGISOL facility using Penning trap techniques. Furthermore, theoretical descriptions of angular momentum generation and evolution in fission models such as GEF and FREYA will be discussed. Results obtained with different analysis frameworks, including the Manchester Spin Method and the TALYS-based Uppsala Spin Method, will also be presented and compared.
The talk will further address current challenges, including the role of fragment deformation and moments of inertia, the treatment of spin cut-off parameters, excitation energy sharing at scission, and the correlation between excitation energy and angular momentum. Finally, perspectives for future progress will be outlined, including the need for new high-precision measurements, improved theoretical descriptions of scission dynamics, and better constraints on angular momentum generation mechanisms in the different types of particle-induced fission.