A low-background neutron detector array was developed to measure the cross section of the 13C(α,n)16O reaction, which is the neutron source for the s-process in AGB stars, in the Gamow window (Ec.m. = 190 ± 40 keV) at the China Jinping Underground Laboratory (CJPL). The detector array consists of 24 3He proportional counters embedded in a polyethylene cube. Due to the deep underground location and a borated polyethylene shield around the detector array, a low background of 4.5(2)/hour was achieved. The 51V(p, n)51Cr reaction was used to determine the neutron detection efficiency of the array for neutrons with energy En< 1 MeV. Geant4 simulations, which were shown to well reproduce experimental results, were used to extrapolate the detection efficiency to higher energies for neutrons emitted in the 13C(α,n) 16O reaction. The theoretical angular distributions of the 13C(α,n)16O reaction were shown to be important in estimating the uncertainties of the detection efficiency.
@article{arxiv.2111.12552,
title = {Development of a low-background neutron detector array},
author = {Y. T. Li and W. P. Lin and B. Gao and H. Chen and H. Huang and Y. Huang and T. Y. Jiao and K. A. Li and X. D. Tang and X. Y. Wang and X. Fang and H. X. Huang and J. Ren and L. H. Ru and X. C. Ruan and N. T. Zhang and Z. C. Zhang},
journal= {arXiv preprint arXiv:2111.12552},
year = {2022}
}