基于β-X射线分析技术的大气颗粒物浓度-元素分析仪研制

Analyzer Design of Atmospheric Particulate Matter's Concentration and Elemental Composition Based onβand X-Ray's Analysis Techniques

针对城市大气颗粒物监测、污染物溯源等工作现场实时分析的迫切需要,研制了基于β-X射线分析技术的大气颗粒物浓度-元素分析仪。以β射线在物质中的衰减规律和能量色散X射线荧光分析原理,通过仪器总体设计、结构设计、FPGA硬件电路设计和软件设计,实现了在线分析大气颗粒物浓度及其元素识别、含量计算等功能;通过制备纯元素颗粒沉积滤膜样品作为大气颗粒物标准样品,完成了分析仪的标定。该分析仪可在线、连续监测大气颗粒物(如TSP,PM10,PM2.5)的质量浓度及其所含的30种元素种类和含量。成都东郊的现场应用显示,分析仪对大气颗粒物的浓度测量值与成都环保局的监测值具有很好的一致性,对颗粒物中所含重金属元素(如As,Hg,Cd,Cr,Pb等)的监测较为灵敏。通过技术性能测试,表明分析仪具备检出限低、快速分析、使用方便等特点,能够满足城市大气监测过程中对颗粒物浓度和元素实时分析的迫切需求,具有较强的现场应用能力。

Monitoring atmospheric particulate matter requires real-time analysis,such as particulate matter＇s concentrations,their element types and contents.An analyzer which is based onβand X rays analysis techniques is designed to meet those demands.Applyingβ-ray attenuation law and energy dispersive X-ray fluorescence analysis principle,the paper introduces the analyzer＇s overall design scheme,structure,FPGA circuit hardware and software for the analyzer.And the analyzer can measure atmospheric particulate matters＇ concentration,elements and their contents by on-line analysis.Pure elemental particle standard samples were prepared by deposition,and those standard samples were used to set the calibration for the analyzer in this paper.The analyzer can monitor atmospheric particulate matter＇s concentration,30 kinds of elements and content,such as TSP,PM10 and PM2.5.Comparing the measurement results from the analyzer to Chengdu Environmental Protection Agency＇s monitoring results for monitoring particulate matters,a high consistency is obtained by the application in eastern suburbs of Chengdu.Meanwhile,the analyzer are highly sensitive in monitoring particulate matters which contained heavy metal elements（such as As,Hg,Cd,Cr,Pb and so on）.The analyzer has lots of characteristics through technical performance testing,such as continuous measurement,low detection limit,quick analysis,easy to use and so on.In conclusion,the analyzer can meet the demands for analyzing atmospheric particulate matter＇s concentration,elements and their contents in urban environmental monitoring.