New Measurement of the 197Au(n, γ) Cross Section at the CSNS Back-n White Neutron Facility

Краткое изложение: A new cross-section measurement of the 197Au(n, γ) reaction has been performed on the C6D6 detection
terminal at the China Spallation Neutron Source (CSNS) Back-n white neutron facility. Compared to the pre-
vious measurement conducted at Back-n, this study employs more accurate analysis methods to obtain higher-
precision results in the energy range of 0.5 eV to 300 keV. Resonance parameters in the resolved resonance
region were extracted from the experimental capture yield using the R-matrix code SAMMY. A comprehensive
comparison shows general consistency between the extracted resonance parameters and the evaluated data from
the ENDF/B-VIII.1 library. However, the capture kernels derived in this work, which have small uncertainties
but deviate significantly from those in ENDF/B-VIII.1, suggest that the current resonance parameters may re-
quire further examination. Furthermore, Maxwellian-averaged cross sections have been computed over a range
of temperatures to provide integrated values across the full energy range, including the unresolved resonance
region. Our results are systematically higher than the other available data, ranging from almost equal to about
7.3% higher. With the total uncertainty reduced to an average of 5.9%, this study offers a valuable reevaluation
of the neutron capture cross section of 197Au.