高灵敏度区域中子监测仪探测效率曲线模拟

Detection efficiency curve simulation of high sensitivity area neutron monitor

中子监测仪对不同能量中子的探测效率是其重要的性能指标,直接影响其测量值的可信度与使用效果。针对中国科学院高能物理研究所生产的高灵敏度区域中子监测仪(HANM型),利用蒙特卡罗软件模拟其探测效率曲线,模拟结果表明该仪器探测效率随能量增加,先上升后下降,其探测效率最高值在1 MeV附近。通过改变模拟条件中的射线入射方向,对比探测效率曲线趋势变化,验证该型仪器的探测效率曲线趋势的可靠性。在此基础上,分别利用D-D,D-T加速器产生2.5 MeV和14 MeV单能中子,对探测效率曲线进行校准与验证,最终获得此型仪器的探测效率曲线。

One of the important performance indexes of the neutron monitor is the detection efficiency for different energy neutrons, which would directly affect the credibility and use of measured value. High sensitivity area neutron monitor produced by the Institute of High Energy Physics, Chinese Academy of Sciences was used to simulate its detection efficiency curve by Monte Carlo software, which shows detection efficiency firstly rises then decreases with the increase in energy, and the highest efficiency is at around 1 MeV. To verify the reliability and to compare trend changes of the detection efficiency curve, ray incident direction used in the simulation was changed. Based on this, 2.5 MeV single-energy neutron and 14 MeV single-energy neutron respectively generated by D-D neutron tube and D-T neutron tube were used to calibrate and verify the detection efficiency curve, and finally the detection efficiency curve of the neutron monitor was made.