A numerical method for quantitatively analyzing the space charge effect of Self-Powered Neutron Detector

•A numerical method for quantitatively analyzing the space charge effect of Self-Powered Neutron Detector was proposed and demonstrated.•The real charge accumulation process in the insulator can be simulated by iterative calculation to obtain the actual stable charge distribution.•For a steady-state problem, the real model and simplified model were provided and validated, showing that the simplified model can obtain the same result with short calculation time.•The actual electric field derived from stable charge distribution can be imported into SPNDSignal to simulate SPND’s response. In this study, a numerical method that can quantitatively analyze the space charge effect of Self-Powered Neutron Detector (SPND) was proposed and successfully applied to SPNDSignal toolkit. By simulating the charge accumulation in SPND’s insulator, the space charge distribution in the insulator under the specified radiation field and detector parameters were obtained. The obtained electric field can be imported into SPNDSignal to construct a real electric field in the insulator, which makes the numerical response calculation model for SPND more real. The feasibility of this method was demonstrated by a calculation for Ag SPND’s space charge distribution and detector response. Moreover, the effect of this method on response calculation of SPND utilized in reactor core was verified by performing the space charge distribution calculation and response calculation for Rh SPND used in VVER assembly, and the results show a good agreement with reference data.