Phys. Rev. Lett. 108, 142502 (2012) - Abrupt Change in Radiation-Width Distribution for $^{147}\mathrm{Sm}$ Neutron Resonances

Abrupt Change in Radiation-Width Distribution for ${}^{147}{Sm}$ Neutron Resonances

P. E. Koehler, R. Reifarth, J. L. Ullmann, T. A. Bredeweg, J. M. O’Donnell, R. S. Rundberg, D. J. Vieira, and J. M. Wouters

Phys. Rev. Lett. 108, 142502 – Published 3 April 2012

Abstract

We obtained the total radiation widths of $s$ -wave resonances through an $R$ -matrix analysis of ${}^{147}{Sm} (n, γ)$ cross sections. Distributions of these widths differ markedly for resonances below and above $E_{n} = 300 eV$ , which is 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, is reflected in abrupt increases in both the average ${}^{147}{Sm} (n, γ)$ 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.

Received 5 December 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.142502

Authors & Affiliations

P. E. Koehler^1,*, R. Reifarth², J. L. Ullmann³, T. A. Bredeweg³, J. M. O’Donnell³, R. S. Rundberg³, D. J. Vieira³, and J. M. Wouters³

¹Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
²Goethe Universität, Frankfurt Am Main, Germany
³Los Alamos National Laboratory, Los Alamos, New Mexico 87454, USA