Ninomiya Satoshi, Sakai Yuji, Chuin Chen Lee, Hiraoka Kenzo
Interdisciplinary Graduate School, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.
Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.
Mass Spectrom (Tokyo). 2018;7(1):A0069. doi: 10.5702/massspectrometry.A0069. Epub 2018 Jul 31.
Atmospheric pressure electrospray had been used in previous studies to generate massive water droplet ion beams, and the beams successfully achieved efficient desorption/ionization of biomolecules, low damage etching of polymers and nonselective etching of metal oxides. However, this droplet ion beam was not practical as a primary ion beam for surface analysis instruments because it required differential pumping and lacked adequate beam current and density. To improve the beam performance, we have proposed to use vacuum electrospray of aqueous solutions as a beam source, and developed a technique for producing a stable electrospray of aqueous solution in vacuum. We also designed a prototype of a vacuum electrospray droplet ion gun, and measured the beam properties. Finally, the applicability of this ion gun in secondary ion mass spectrometry is discussed.
在先前的研究中，大气压电喷雾已被用于产生大量水滴离子束，并且这些离子束成功实现了生物分子的高效解吸/电离、聚合物的低损伤蚀刻以及金属氧化物的非选择性蚀刻。然而，这种水滴离子束作为表面分析仪器的一次离子束并不实用，因为它需要差动抽气，并且缺乏足够的束流和束流密度。为了提高束流性能，我们提出使用水溶液的真空电喷雾作为束流源，并开发了一种在真空中产生稳定水溶液电喷雾的技术。我们还设计了一种真空电喷雾滴离子枪的原型，并测量了束流特性。最后，讨论了这种离子枪在二次离子质谱中的适用性。
