二次离子质谱的一次离子光学系统

摘要

二次离子质谱仪作为一种强大的表面分析工具,在表面分析领域有着非常广泛的应用.本文报道了一种用于二次离子质谱仪的一次离子光学系统,它可以对电子轰击电离源产生的一次离子进行有效的加速与聚焦,形成稳定的、能量在0～5 kV范围内连续可调的离子束流.同时,该光学系统可以在两种聚焦模式下工作,产生两种不同性能的离子束流.实验结果表明,采用电子轰击电离源作为一次离子源的条件,该离子光学系统能够将离子束聚焦至直径为20 μm的束斑,其一次离子束流密度最高可达到503.2 mA/cm2,可以实现对一般样品(如材料或生物样品)的表面成分分析.%Secondary ion mass spectrometry (SIMS) is a powerful surface analysis technique, and which was used in many fields. This paper reports a new type of the primary ion optics of SIMS, which consists of two ion condenser lens. It can be used to accelerate and focus the primary ions effectively, and produces a stable primary ion beam with adjustable energy in the range of 0 - 5 keV. Furthermore, by changing the voltage distribution at the two lens, this ion optics can be switched between two different focusing patterns and form two kinds of ion beams. The experimental results show that the primary ions produced using electron impact (EI) can be focused to around 20 μm in diameter with the ion current density of 503. 2 Ma/cm2.