Excitation energy, angular momentum, and deformation of the neutronless fragmentation in (sf)
Phys. Rev. C 113, 034610 – Published 17 March, 2026
DOI: https://doi.org/10.1103/qw2h-8vsf
Abstract
We investigate the radiative decay of fragments populated in neutronless spontaneous fission of , accurately identified using the double-energy method. The present study focuses on the channel for which we measure the total excitation-energy distribution. The properties of the gamma-ray spectrum associated with this channel, and its evolution with total excitation energy, allow us to extract the excitation-energy and spin distributions at scission for each fragment. We find that the heavy fragment remains weakly excited, most of the excitation energy being carried away by its light partner. A sizable width of about 1.3 MeV in the excitation-energy distribution is required to reproduce the data. The evolution with excitation energy of the spin-cutoff parameter of the fragments is well accounted for by a temperature law incompatible with large angular-momentum removal by neutrons. Comparison with calculations performed with the microscopic scission-point model spy shows that it underestimates the deformation of the light fragment and supports the orientation-pumping mechanism for angular-momentum generation in fission.
