Neutron capture measurement of the 165Ho at the CSNS Backn facility in the resonance energy region

TL;DR

This study measured the neutron capture cross sections of 165Ho at the CSNS facility, analyzing resonance structures and neutron strength functions, revealing chaotic nuclear behavior and confirming existing data with high precision.

Contribution

The paper presents new neutron capture measurements of 165Ho using a total absorption detector and Bayesian analysis, providing detailed resonance parameters and neutron strength functions.

Findings

Resonance parameters for 18 s-wave resonances were extracted.

The level-spacing distribution follows a Wigner-Dyson form, indicating chaos.

The neutron strength function agrees with existing nuclear data.

Abstract

The neutron capture yield of 165Ho have been measured at the Back-streaming White neutron beam line (Back-n) of the China Spallation Neutron Source (CSNS) using a 4{\pi} BaF2 Gamma Total Absorption Facility (GTAF). The resonance shapes in the 1eV to 1.0keV region were analyzed with the Bayesian R-matrix code SAMMY. For 18 s-wave resonances below 100eV, the resonance energy ER, neutron width {\Gamma}n, and radiative width {\Gamma}{\gamma} were extracted. The statistical analyses of the resonance parameters show that the nearest-neighbour level-spacing distribution follows a Wigner-Dyson form with mean spacing D0 = 4.53(3)eV,indicating chaotic compound-nucleus behaviour; Using the extracted parameters, the s-wave neutron strength function for 165Ho was derived to be 10-4S0 = 2.01(1), in excellent agreement with the values reported in both the Atlas of Neutron Resonances and ENDF/B-VIII.0 data.