[Table of Contents]

Plasma and Fusion Research

Volume 6, 2406100 (2011)

Regular Articles

Development of a 14 GHz Microwave H− Source
Motoi WADA, Yasuhiro DEMURA, Toshiro KASUYA, Takahiro KENMOTSU1), Shuichi MAENO2), Tomoaki NISHIDA, Masaki NISHIURA3), Katsuhiro SHINTO4) and Hitoshi YAMAOKA5)
Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
1)
Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
2)
Novelion Systems Co. Ltd , Kyotanabe, Kyoto 610-0394, Japan
3)
National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
4)
Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212, Japan
5)
Riken, Harima, Hyogo 679-5148, Japan
(Received 7 December 2010 / Accepted 15 April 2011 / Published 27 July 2011)

Abstract

Microwave power at 14 GHz has excited a H2 plasma in a 2 cm inner diameter 9 cm long alumina tube to generate negative hydrogen ion (H−) beam. A pair of permanent magnets created a magnetic field with the intensity corresponding to an electron cyclotron resonance condition for the input microwave. The ion source produced stable plasmas with the H2 pressure more than 0.5 Pa, while the amount of H− current decreased exponentially against increasing ion source pressure above 0.6 Pa. When the source produced H− beam with constant H2 pressure at 0.6 Pa, the H− beam current saturated against the increase of microwave power above 200 W. These characteristics of the H− beam current indicate poor transport of vibrationally excited hydrogen molecules and that of H− to the ion extraction electrode.

Keywords

negative ion source, electron cyclotron resonance, vibrationally excited molecule, ion beam diagnostics

DOI: 10.1585/pfr.6.2406100

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This paper may be cited as follows:

Motoi WADA, Yasuhiro DEMURA, Toshiro KASUYA, Takahiro KENMOTSU, Shuichi MAENO, Tomoaki NISHIDA, Masaki NISHIURA, Katsuhiro SHINTO and Hitoshi YAMAOKA, Plasma Fusion Res. 6, 2406100 (2011).