激光共振电离质谱及其在核技术中的应用

Resonance Ionization Mass Spectrometry and Its Application in Nuclear Technology

激光共振电离质谱是激光共振电离技术和质谱技术相结合的一种新型质谱分析技术,具有高元素选择性和高灵敏度的特点,能有效克服商业质谱仪存在的同量异位素干扰难题。为满足复杂基体干扰下超痕量核素分析测量的需求,实验室研制了一台基于磁-电双聚焦质量分析器的激光共振电离质谱仪。该装置的质量分析器采用正向Nier-Johnson型双聚焦结构,由柱形静电分析器和扇形磁质量分析器组成。本文介绍了仪器质量分析器的结构和理论参数,并对其进行理论仿真与实验测试。结果表明,该仪器实现了方向和能量双方向聚焦,具有较小的高阶像差,仪器的水平方向放大率为0.78,质量色散达到500 mm,当源狭缝宽度0.25mm、探测器入口狭缝宽度0.65mm时,质量分辨率(10%峰谷)达到580左右,接近质量分辨率的理论极限605。最后,介绍了本实验室利用该仪器开展的分析测量工作,展示了该装置在强同量异位素干扰下超痕量核素测量方面的部分应用情况。

Resonance ionization mass spectrometry is a new mass spectrometry technology formed by the combination of resonance ionization technology and mass spectrometry technology,which has the characteristics of element selectivity and high sensitivity,and can effectively overcome the problem of isobaric interference faced by commercial mass spectrometer.In order to meet the application requirement of ultra-trace nuclide analysis and measurement under complex matrix interference,a laser resonance ionization mass spectrometer based on magnetic-electric double focusing mass analyzer was developed in the laboratory.A forward Nier-Johnson double focusing structure,which was consisted of a cylindrical electrostatic analyzer and a sector magnetic mass analyzer was adopted for the mass analyzer.Firstly,the structure and theoretical parameters of the mass analyzer were introduced.Secondly,the results of theoretical simulation and experimental test were given.It showed that the instrument had achieved bidirectional focusing of direction and energy,and had small higher order aberration.The horizontal magnification and mass dispersion of the instrument were 0.78 and 500 mm,respectively.When the width of the source slit was 0.25 mm and the width of the detector entrance slit was 0.65 mm,the mass resolution(10%valley)reached about 580,which was close to the theoretical limit of mass resolution.Finally,the analysis and measurement work carried out by the laboratory on the instrument was introduced,and some applications of the device in ultra-trace radionuclide measurement under strong isotope interference were shown.