Effects of the extraction voltage on the beam divergence for a H- ion source

M. Lindqvist, S. Nishioka, K. Miyamoto, K. Hoshino, J. Lettry, Akiyoshi Hatayama

Research output: Contribution to journalArticle

Abstract

Negative hydrogen (H-) ion sources have a wide range of applications. The general requirement for these H-ion sources is to produce intense H-ion beams with good beam optics. The purpose of this paper is to clarify the effects of the beam extraction voltage on the beam divergence angle by three-dimensional Particle-in-Cell (PIC) modeling. Perveance matching has been studied for a wide range of the extraction voltage with the model geometry of a Linac4 H-ion source. The extracted H-beam divergence angle is evaluated for extraction voltages ranging from 7 to 14 kV by using the Keio-BFX PIC code. The results show divergence minima in the range of 9.2-11.5 kV for the case without surface H-production, which correspond to experimental results. The dependence of divergence on the extraction voltage is explained by the change of the shape of the meniscus. In particular, a flat meniscus corresponds to low beam divergence, and particles extracted through the center of the meniscus have a lower divergence than particles extracted near the Plasma Electrode.

Original languageEnglish
Article number123303
JournalJournal of Applied Physics
Volume126
Issue number12
DOIs
Publication statusPublished - 2019 Sep 28

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Lindqvist, M., Nishioka, S., Miyamoto, K., Hoshino, K., Lettry, J., & Hatayama, A. (2019). Effects of the extraction voltage on the beam divergence for a H- ion source. Journal of Applied Physics, 126(12), [123303]. https://doi.org/10.1063/1.5116413