磁质谱高丰度灵敏度阻滞过滤器研制与性能测试  

Development and Performance Evaluation of High Abundance Sensitivity Retarding Filter for Magnetic Mass Spectrometer

作　　者：袁祥龙 沈小攀[1] 翟利华[1] 李飞腾 邓虎[1] 徐江[1] 冯磊 李志明[1] YUAN Xiang-long;SHEN Xiao-pan;ZHAI Li-hua;LI Fei-teng;DENG Hu;XU Jiang;FENG Lei;LI Zhi-ming(Northwest Institute of Nuclear Technology,Xi’an 710024,China)

机构地区：[1]西北核技术研究所,陕西西安710024

出　　处：《质谱学报》2024年第5期600-608,共9页Journal of Chinese Mass Spectrometry Society

基　　金：国家重点研发计划(2021YFF0700100)。

摘　　要：阻滞过滤器是商用磁质谱仪提高丰度灵敏度的关键部件。本研究基于离子光学基本原理,利用离子光学仿真软件SIMION8.1设计了由5个电极构成的阻滞过滤器,其结构小巧,尺寸仅为(40×50×50) mm3。在能量筛选基础上,该阻滞过滤器还具备方向筛选功能,极大地增强了对杂散离子的滤滞能力。将该阻滞过滤器应用于国产热表面电离质谱仪,并进行不同电压条件下传输效率和丰度灵敏度的测试。结果表明,在不影响主离子束传输效率和峰形的基础上,该阻滞过滤器成功将该仪器的丰度灵敏度指标从<2×10^(-6)提升至<5×10^(-9),丰度灵敏度极限为2×10^(-9),优于目前商用热表面电离质谱仪。本文所设计的阻滞过滤器可为国产高性能磁质谱仪的研制提供重要的技术支撑。Abundance sensitivity is an important technical index of magnetic mass spectrometer,which describes the extent to which the tailing of intense ion peaks at a mass number in its neighborhood affects the weak ion peaks during isotope ratio measurement.It is particularly important in the measurement of isotope ratios containing low abundance nuclides,such as 234U/238U,236U/238U,and 230Th/232Th.However,the abundance sensitivity of magnetic mass spectrometer is only of the order of 10^(-6) without taking additional technical measures.To further improve the abundance sensitivity,the techniques of tandem mass spectrometer,such as magnetic-electric,magnetic-magnetic and magnetic-electric-quadrupole tandem mass spectrometer,and retarding filter can be adopted.In fact,while various tandem mass spectrometer techniques can effectively improve the abundance sensitivity of an instrument,they also significantly increase the size,complexity,and cost of instrument,and therefore are not widely used.In contrast,due to its simple structure,small size,and excellent performance,the retarding filter has become a key component for commercial magnetic mass spectrometers to improve abundance sensitivity.Based on the basic principles of ion optics,a retarding filter consisting of five electrodes with a compact structure of only(40×50×50)mm^(3) was developed by utilizing the ion optics simulation software SIMION8.1.In addition to the function of energy retarding,the retarding filter also has the function of direction retarding,which greatly enhances the filtering capability to scatter ions.To test the ion transmission efficiency and the abundance sensitivity under different voltages,the retarding filter was installed on a domestic double-focusing thermal ionization mass spectrometer(TIMS).The instrument mainly consists of a thermal ionization source,a double focusing mass analyzer consisting of an electrostatic analyzer and a magnetic mass analyzer,a zoom lens,and a multi-collector detector,which can be configured with up to 16 faraday cu

关 键 词：热表面电离质谱(TIMS) 丰度灵敏度 阻滞过滤器 杂散离子 传输效率 

分 类 号：O657.63[理学—分析化学]