基于碳化硼慢化体和涂硼微结构中子探测器的通用中子能谱仪设计和解谱方法研究

A general neutron spectrometer design method based on boron moderator and boron-coated micro-structure neutron detectors

摘要:

本文提出了一种基于碳化硼慢化体和涂硼微结构中子探测器的通用中子能谱仪设计方法, 获得了计算最优慢化体厚度和探测器响应函数的通用公式, 并用蒙特卡罗方法进行了验证和修正, 可实现对中子能谱仪的快速设计. 该类能谱仪可实现各中子响应函数之间的解耦, 使每个探测器对各个分立能量区间的中子最为敏感, 具有较强适用性和灵活性. 基于该方法, 我们设计了一个用于硼中子俘获治疗（BNCT）超热中子能谱测量的能谱仪, 通过Gravel算法实现了中子能谱解析, 并提出了一种具有良好普适性的基于响应函数的预置谱设置方法. 结果表明, 该能谱仪对单能中子的峰位解析精度约为1%, 对BNCT连续谱的解析均方差约为0.76%, 具有较大技术优势和可行性.

Abstract:

In this paper, a general neutron spectrometer design method based on boron carbide moderators and boron-coated micro-structure neutron detectors is proposed. The formula for calculating the optimal moderator thickness and detector response function according to the neutron energy is obtained, which is verified and modified by the Monte Carlo simulation. The formula is able to realize the rapid design of the neutron spectrometer effectively. This kind of energy spectrometer can realize the decoupling of neutron response functions, so that each detector is most sensitive to neutrons in each discrete energy range, and has strong applicability and flexibility. An epithermal neutron spectrometer for boron neutron capture therapy (BNCT) is designed based on the proposed method, the response function of the spectrometer is calculated and the neutron spectrum unfolding is achieved by the Gravel algorithm. The results show that the resolution accuracy of the energy spectrometer to the peak position of monoenergetic neutrons is about 1%, and the analytical mean square error of the BNCT continuous spectrum is about 0.76%, which has great technical advantage and feasibility.