Neutron capture cross section of 169Tm measured at the CSNS Back-n facility in the energy region from 30 keV to 300 keV

Abstract The capture cross sections of the 169 Tm(n, γ) reaction were measured at the back streaming white neutron beam line (Back-n) of the China Spallation Neutron Source (CSNS) using four C 6 D 6 liquid scintillation detectors. To obtain accurate cross sections, the background subtraction, normalization, and correction were carefully taken into consideration in the data analysis. For the resonance at 3.9 eV, the R-matrix code SAMMY was used to determine the resonance parameters with internally normalization method. While the average capture cross sections of 169 Tm in the energy range between 30 keV and 300 keV were extracted relative to the 197 Au(n, γ) reaction. The measured cross sections of the 169 Tm(n, γ) reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4%-7.0% in this paper, and described in terms of average resonance parameters by means of a Hauser-Feshbach calculation with fluctuations. Both of the point-wise cross sections and the averge resonance parameters showed fair agreement with the evaluated values of ENDF/B-VIII.0 library in the energy region studied.