Abrupt Change in Radiation-Width Distribution for 147Sm Neutron Resonances

TL;DR

This paper reports an unexpected abrupt change in the distribution of radiation widths for 147Sm neutron resonances around 300 eV, challenging established theories and impacting nuclear applications.

Contribution

It reveals a significant, previously unrecognized change in radiation-width distributions for 147Sm resonances, supported by R-matrix analysis and experimental data.

Findings

Distribution of radiation widths differs below and above 300 eV

Abrupt increase in average 147Sm(n,gamma) cross section near 300 eV

Potential implications for nuclear astrophysics and safety

Abstract

We obtained total radiation widths of s-wave resonances through R-matrix analysis of 147Sm(n,gamma) cross-sections. Distributions of these widths differ markedly for resonances below and above 300 eV, in stark contrast to long-established theory. We show that this change, as well as a similar change in the neutron-width distribution reported previously, are reflected in abrupt increases in both the average 147Sm(n,gamma) cross section and fluctuations about the average near 300 eV. Such effects could have important consequences for applications such as nuclear astrophysics and nuclear criticality safety.