Microscopic description of target spin distribution after inelastic scattering to the continuum

¹ CEA, DAM, DIF, 91297 Arpajon, France
² Université Paris-Saclay, CEA, Laboratoire Matière sous Conditions Extrêmes, 91680 Bruyères-Le-Châtel, France
³ Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
⁴ Université de Strasbourg, CNRS, IPHC/DRS UMR 7178, 23 rue du Loess 67037 Strasbourg, France

^* Corresponding author: marc.dupuis@cea.fr

Published online: 26 May 2023

Abstract

Microscopic modeling of inelastic scattering to the continuum is applied to neutron induced reaction on spherical and axially deformed even-even targets. The spin distributions of the residual compound nucleus formed after the fast inelastic process are calculated with two microscopic models and compared to the prescription usually associated to the semi-classical exciton model. As the semi-classical exciton model does not account for angular momentum conservation, it is often assumed that it is the same as the compound nucleus spin distribution, but this forgets the dynamics of the reaction. It is found that microscopic approaches drastically reduce the average spin value in comparison to what was previously assumed. This strongly impacts (n,n’ γ) as well as isomer production cross sections when high spin levels are involved. New spin cut-off parameters are deduced from the microscopic calculations that can be used as an alternative to previous prescriptions which neglect the reaction dynamics when they are applied in the context of pre-equilibrium emission process.