Threshold Resonant Structure of the 232Th Neutron-Induced Fission Cross Section

TL;DR

This paper investigates the sub-threshold neutron-induced fission of 232Th using a new model, revealing detailed resonance structures and spin contributions with good agreement to experimental data.

Contribution

It introduces a theoretical model based on solving coupled differential equations for a two-humped barrier to explain resonance structures in 232Th fission.

Findings

Structures at 1.4 and 1.6 MeV are dominated by spin 3/2 partial cross-section.

Structure at 1.7 MeV is mainly due to spin 5/2 partial cross-section.

Good agreement with experimental data was achieved using few parameters.

Abstract

The structures observed in the sub-threshold neutron-induced fission of ^{232}Th were investigated employing a recent developed model. Theoretical single-particle excitations of a phenomenological two-humped barrier are determined by solving a system of coupled differential equations for the motion along the optimal fission path. A rather good agreement with experimental data was obtained using a small number of independent parameters. It is predicted that the structure at 1.4 and 1.6 MeV is mainly dominated by spin 3/2 partial cross-section with small admixture of spin 1/2, while the structure at 1.7 MeV is given by a large partial cross section of spin 5/2.