基于多元定标法的矿物铀元素光纤式激光诱导击穿光谱定量分析  

Quantitative Measurement of Uranium in Ore Using Fiber⁃Optic Laser⁃Induced Breakdown Spectroscopy and Multivariate Calibration

作　　者：郭歆宇 吴坚[1] 时铭鑫 朱欣欣[2] 邱岩 李京徽 吴迪[1] 宋自远 Guo Xinyu;Wu Jian;Shi Mingxin;Zhu Xinxin;Qiu Yan;Li Jinghui;Wu Di;Song Ziyuan(State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China;China Academy of Atomic Energy Sciences,Beijing 102413,China;Ministry of Education Key Laboratory of Electronic Physics and Devices,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China)

机构地区：[1]西安交通大学电气绝缘与电力设备国家重点实验室,陕西西安710049 [2]中国原子能科学研究院,北京102413 [3]西安交通大学电子物理与器件教育部重点实验室,陕西西安710049

出　　处：《中国激光》2024年第8期234-243,共10页Chinese Journal of Lasers

基　　金：国家重点研发计划青年科学家项目(2021YFB3703200);中核集团青年英才项目;国家自然科学基金(62205266);中国博士后科学基金(2022M712514)。

摘　　要：针对核工业辐照环境下铀等元素组分远程测量的需求,基于光纤式激光诱导击穿光谱系统,研究了铀矿石样品中铀元素谱线强度的影响因素及其定量测量方法。在实验中,采用光纤传输30 mJ脉冲激光并将其聚焦在铀矿石粉末压片上产生激光诱导等离子体,然后通过同轴光纤回传等离子体自发光。首先,研究了气氛环境对铀元素谱线的影响。结果显示:氦气气氛下铀质量分数为0.425%的样本的U II 409.013 nm谱线的信噪比相比空气气氛下提高了1.37倍,同时,氦气气氛下铀质量分数为0.0726%的样本的U II 409.013 nm谱线的信噪比达到了8.9。其次,根据谱线信噪比、信背比和净强度将系统的探测延时优化至1000 ns。最后,提出了一种基于内标法原理的多元线性定标方法,通过引入基质元素与铀的谱线比值进行回归,使得铀的检测限达到142 mg/kg,定量限达到426 mg/kg。与基于谱线峰值的单变量回归方法相比,所提多元线性定标方法将铀元素的定标决定系数R2从0.9711提升到0.9984,均方根误差从0.200%减小到0.0404%。本文方法和研究结果可为铀元素含量的测量提供技术支撑。Objective The nuclear industry is a strategic high-tech industry and an important cornerstone of national security.It involves various areas,such as ore exploration and mining,uranium extraction,isotope separation,reactor power generation,and spent fuel reprocessing.The uranium content of uranium ores is an important criterion for identifying uranium ore types and evaluating their developmental value.The rapid collection of uranium distribution information is necessary for geographical exploration.In particular,this is true for China,where uranium deposits are scattered and ore bodies are relatively small.Laser-induced breakdown spectroscopy(LIBS)is an atomic emission spectroscopy technique that involves irradiating the sample surface with nanosecond pulse lasers(typically at irradiance levels above GW/cm²).The irradiated material on the sample surface is rapidly heated,melted,vaporized,and partially ionized,forming laser-induced plasma(LIP).The elemental composition of the sample material can be measured by analyzing the emission spectra of the plasma.Fiber-optic LIBS(FO-LIBS)is an LIBS system that utilizes optical fibers for laser transmission and simultaneous collection of plasma emission spectra.It uses flexible,long optical fibers to transmit pulse lasers and spectral signals,which make it more suitable for complex and confined spaces in the field than conventional LIBS.Measurement distances can reach tens of meters.This study addresses the demand for the rapid,in-situ,and on-site detection of uranium in the nuclear industry and establishes a laboratory-based FO-LIBS system for investigating the evolution characteristics of uranium emission spectral lines in plasma under a helium atmosphere.Furthermore,it provides parameter optimization schemes and explores the matrix effects of uranium ore samples.A multivariate calibration method for quantitative analysis is proposed,which effectively improves calibration and prediction accuracy while ensuring model generalization performance.This provides a new approach

关 键 词：光谱学 激光诱导击穿光谱 铀矿 元素检测 多元定标法 

分 类 号：O433.4[机械工程—光学工程]