基于磁场增强的射频辉光放电质谱技术与体系建立

For radio frequency glow discharge mass spectrometry (rf-GD-MS), the relative low signal intensity or sensitivity for the analysis of semi-conducting and insulating materials has restrained the development and application in new material filed. In the present project, the magnetic enhancement technique and system for radio frequency glow discharge mass spectrometry will be established to improve the signal intensity and sensitivity. Firstly, several models of magnetic enhancement devices such as stacked magnet, planar array magnet, and ring magnet and so on will be designed and set up, and the possible mechanism for the signal enhancement will be studied by using the ANSYS and Monte Carlo methods. Then, according to the theoretical studies, several devices will be designed and prepared after the optimization of the strength, size, combination method, materials for metal shells and so on. Furthermore, some semi-conducting and insulating samples will be tested to investigate the performance of different types of magnetic enhancement devices, and the response property of magnet to different materials will be studied to improve rf-GD-MS technique. Finally, the method of measuring the plasma density will be used for the validation of the signal enhancement mechanism, and main favorable factors will be probed to establish the techniques and systems for radio frequency glow discharge mass spectrometry based on the magnetic enhancement. The present studies will be hoped to offer great promises in boosting the development of rf-GD-MS and providing a sensitive, stable, and facile solution for analyzing the new materials.

针对射频辉光放电质谱(rf-GD-MS)分析半导体、非导体材料时离子信号强度低、灵敏度低等问题，本项目拟以运用磁场增强机制提高rf-GD-MS分析信号与灵敏度为目的，建立基于磁场增强的射频辉光放电质谱技术与体系。首先，建立堆积、阵列、环形等磁场与金属外壳组合而成的系列磁场增强装置模型，运用ANSYS与Monte Carlo等方法系统研究磁场增强射频辉光放电机理；根据理论结果，优化磁场强度、排布方式与金属外壳材料，制作组合磁场增强装置；进一步，选用半导体、非导体(陶瓷、晶体等)材料，考察不同装置增强射频辉光放电的性能，研究磁场源信号对不同材料的响应特性；最后，运用等离子体密度测定等方法阐释磁场增强作用过程中电子运动路径的延长、与中性粒子等碰撞几率的增加，探讨提高rf-GD-MS离子信号强度与灵敏度的有利因素，建立磁场增强射频辉光放电质谱技术与体系，促进rf-GD-MS的发展与应用。

辉光放电质谱法(GD-MS)因具有直接分析固体材料种痕量/超痕量元素的独特优势，已经成为先进材料研发与生产过程中不可或缺的重要表征手段。然而，射频辉光放电质谱 (rf-GD-MS) 在分析半导体、非导体材料时，会出现离子信号强度降低、分析灵敏度降低等问题，制约了rf-GD-MS 的发展与应用。本项目围绕上述问题，提出了磁场增强射频辉光放电离子化的机制与策略。基于COMSOL方法研究揭示了在磁场与电场共同作用下，电子作拉莫尔进动，其运动路线发生螺旋式弯曲与延长，增加与其他粒子的碰撞几率，进而提高离子化效率与离子信号强度。基于理论研究构建了rf-GD-MS堆积、阵列与环形3种磁场增强技术体系，应用于BGO、PWO、GGAG、LYSO、LuAG等晶体与陶瓷的分析，获得基体元素的信号强度与无磁铁情况下相比提高了2-4个数量级，痕量元素的离子信号强度提高了1-2个数量级，有效解决了rf-GD-MS分析离子信号强度与分析灵敏度低的关键问题。