摘要
瞬发γ中子活化分析(Prompt Gamma Neutron Activation Analysis,PGAA)是一种具有高灵敏度、非破坏性的多元素在线分析技术,其独特的优势在于对H、B等轻元素的高探测灵敏度,有效弥补了仪器中子活化分析(Instrumental Neutron Activation Analysis,INAA)在轻元素检测方面的局限,在核材料分析、文物考古、半导体材料以及矿石成分检测等领域具有广阔的应用前景。中国原子能科学研究院基于中国先进研究堆(CARR)中子科学平台搭建了PGAA装置,测量了系统本底谱及NH_4Cl样品瞬发γ谱,依据^(35)Cl(n,γ)产生的高能特征瞬发γ射线,结合^(152)Eu、^(60)Coγ源完成0.1~8.5 MeV宽能区的能量刻度和相对效率刻度,最后对一系列样品谱进行性能表征。本文基于实验能谱分析及与国内外同类装置参数的对比,评估了CARR PGAA装置的性能,并以进一步改善元素分析灵敏度和探测限为目标提出PGAA装置改进方向,通过蒙特卡罗仿真模拟对PGAA装置进行优化。仿真结果表明,优化后的PGAA装置在屏蔽性能方面实现了显著提升,靶室外表面中子剂量率降低至原水平的约1/4,本底计数率降低至原水平的约1/7,在采用BGO反康系统后,康普顿坪降低至原水平的约1/4,特征峰峰康比显著提高,为后续装置升级改造开展高精度多元素分析研究奠定了重要基础。
Prompt Gamma neutron activation analysis(PGAA)is a high-sensitivity,non-destructive multi-element online analytical technique.Its unique advantage lies in its high detection sensitivity for light elements such as H and B,effectively compensating for the limitations of instrumental neutron activation analysis(INAA)in light element detection.It has broad application prospects in fields such as nuclear material analysis,archaeological relics,semiconductor materials,and ore composition analysis.The China academy of atomic energy research has established a PGAA device based on the neutron science platform of the China advanced research reactor(CARR),measuring the system's background spectrum and the prompt Gamma spectrum of NH4Cl samples.Based on the high-energy characteristic prompt Gamma rays generated by 35Cl(n,γ),combined with ^(152)Eu and ^(60)Co Gamma sources,energy calibration and relative efficiency calibration over the energy range of 0.1-8.5 MeV were completed,followed by the measurement of a series of sample spectra for performance characterization.This article evaluates the performance of the CARR PGAA device based on experimental data analysis and a comparison with similar domestic and international devices.It proposes directions for improving the sensitivity and detection limits of element analysis,optimising the PGAA device through Monte Carlo simulations.The simulation results indicate a significant enhancement in the shielding performance of the optimised PGAA device,with the neutron dose rate on the outer surface of the target chamber reduced to about 1/4 of the original level,and the background counting rate reduced to about 1/7 of the original level.Following the use of the BGO anti-Compton system,the Compton plateau has been reduced to about 1/4 of the original level,significantly enhancing the peak-to-Compton ratio of low-intensity characteristic peaks,laying an important foundation for conducting high-precision multi-element analytical research in subsequent device upgrades.
作者
王唯
姚永刚
肖才锦
邹之全
赵梁
许小雨
WANG Wei;YAO Yonggang;XIAO Caijin;ZOU Zhiquan;ZHAO Liang;XU Xiaoyu(China Institute of Atomic Energy,Institute of Nuclear Physics,Beijing 102413,China;China Institute of Atomic Energy,Department of Reactor Engineering Technology,Beijing 102413,China)
出处
《中国无机分析化学》
北大核心
2025年第11期1890-1900,共11页
Chinese Journal of Inorganic Analytical Chemistry
基金
国家自然基金资助项目(12375305)
秦始皇帝陵博物院青年开放基金项目(Qkfkt202108)。
