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摘要
中文摘要
多层平行极板涂硼电离室是热中子探测的核心器件，离子出射率直接决定探测器探测性能。本研究针对热中子垂直入射场景，聚焦涂层厚度与层数对离子出射率（气隙出射离子与入射中子的比值）的调控机制，通过理论推导与数值仿真开展系统探究。基于热中子与 ¹⁰B 的核反应特性，综合中子在硼层的衰减规律及 α 粒子、⁷Li 重带电粒子的出射行为，建立多层结构离子出射率理论计算模型；利用 Geant4 蒙特卡罗工具构建仿真体系，验证理论模型的准确性。研究表明：随着硼层数增加，离子出射率最优涂硼厚度逐渐减小，且最优条件下的出射率呈显著上升趋势，理论与仿真结果吻合度优异。此外，初步探讨了其他关键因素的影响规律。本研究为多层涂硼电离室的结构参数优化提供了重要理论支撑与数据参考，对提升热中子探测性能具有实际意义。
Abstract
Multi-layer parallel-plate boron-coated ionization chambers are core devices for thermal neutron detection, and the ion emission rate directly determines the detection performance. Focusing on the regulation mechanism of coating thickness and layer number on ion emission rate (ratio of ions emitted into the gas gap to incident neutrons) under normal incidence of thermal neutrons, this study conducts systematic investigations through theoretical derivation and numerical simulation. Based on the nuclear reaction characteristics between thermal neutrons and ¹⁰B, considering the attenuation law of neutrons in boron layers and the emission behavior of heavy charged particles (α particles and ⁷Li ions), a theoretical calculation model for ion emission rate of multi-layer structure is established. A simulation system is constructed using Geant4 Monte Carlo tool to verify the accuracy of the theoretical model. The results show that with the increase of boron layer number, the optimal boron coating thickness for ion emission rate decreases gradually, and the emission rate under optimal conditions shows a significant upward trend, with excellent consistency between theoretical and simulation results. In addition, the influence laws of other key factors are preliminarily discussed. This study provides important theoretical support and data reference for the optimization of structural parameters of multi-layer boron-coated ionization chambers, and has practical significance for improving the performance of thermal neutron detection.
| 关键词 | 中子探测；硼中子转换；离子出射 |
|---|---|
| Keywords | Neutron detection; Boron neutron conversion; Ion emission |
