Study of the multi-parameter performance impact of the n–γ response function of a water-pumping-injection single-sphere neutron spectrometer

To enhance the performance of the water-pumping-injection single-sphere neutron spectrometer (CLYC-WSNS), the n–γ response function of CLYC-WSNS in the neutron energy range of 10^–9–20 MeV is calculated using Monte Carlo simulations. Multiple parameters such as the water temperature, auxiliary material lead layer, and type of nuclear reaction are investigated. First, the effect of water temperature is negligible within the energy region of the neutron response peak, with the fluctuation of the prompt gamma response being within 3.0% at most energy points. Second, the lead layer significantly suppresses the prompt gamma response, with the level of suppression being influenced by the water layer thickness and lead layer position. Except when the outer three-layer gaps are filled with air, the lead layer demonstrates an average suppression ability on the prompt gamma response exceeding 10.0%, reaching up to 27.0% in some cases. Third, the contribution of the ⁶Li(n, t) reaction surpasses 99.5% for all the measurement units except for energies above 1 MeV. Additionally, the maximum contributions of the ³⁵Cl(n, p) and ³⁵Cl(n, α) reactions are 26.5% and 17.0%, respectively. Finally, an evaluation of the anisotropy effect is conducted, which reveals that the neutron and prompt gamma responses exhibit significant angular dependence, with maximum values of 95.8% and 53.5%, respectively. Overall, this work provides a comprehensive analysis of the n–γ response function characteristics of the CLYC-WSNS system, offering support and a theoretical foundation for accurate measurements in various application scenarios and assisting in system performance optimization.