三电极束引出系统的电场穿透对氢负离子源等离子体的影响。

Influence of electric field penetration by a three-electrode beam extraction system on hydrogen negative ion source plasma.

作者信息

Matsumoto Y, Nishiura M, Yamaoka H, Sasao M, Wada M

机构信息

Tokushima Bunri University, Nishihama, Yamashiro, Tokushima 770-8514, Japan.

Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.

出版信息

Rev Sci Instrum. 2014 Feb;85(2):02A720. doi: 10.1063/1.4833918.

DOI:10.1063/1.4833918

PMID:24593454

Abstract

We study influence of electric field penetration into H(-) ion source plasma with three-electrode beam extraction system. Clear change in the plasma potential due to the field penetration is observed in case of low gap voltage between a plasma electrode and an extraction electrode. Influence of lens voltage on the second electrode, which is normally utilized to focus the extracted beam, on ion source plasma is evaluated separating contributions of H(-) density in the plasma and extraction probability of H(-) ions from the plasma by two kinds of photodetachment techniques. In our operation condition, we found that the lens voltage is also useful to enhance the H(-) density in the plasma, though it negatively affects the extraction probability.

摘要

我们研究了具有三电极束流引出系统的电场对H⁻离子源等离子体的影响。在等离子体电极和引出电极之间的间隙电压较低的情况下，观察到由于电场穿透导致的等离子体电位的明显变化。通过两种光致离解技术，分别评估了通常用于聚焦引出束流的第二电极上的透镜电压对离子源等离子体的影响，这两种技术分别考虑了等离子体中H⁻密度的贡献以及H⁻离子从等离子体中的引出概率。在我们的运行条件下，我们发现透镜电压虽然对引出概率有负面影响，但也有助于提高等离子体中的H⁻密度。