Plasma and Fusion Research

Volume 14, 3401094 (2019)

Regular Articles

Investigation of Dependence of Power Transfer on Frequency in the Linac4 Negative Hydrogen Ion Source
Wakaba KOBAYASHI, Kenjiro NISHIDA, Daniel NOLL1), Jacques LETTRY1), Kazuo HOSHINO and Akiyoshi HATAYAMA
Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
1)
CERN, 1211 Geneva 23, Switzerland
(Received 9 January 2019 / Accepted 10 April 2019 / Published 19 June 2019)

Abstract

Linac4 is radio frequency (RF) driven type negative hydrogen H− ion source. In the RF system, it is required to match the impedance between the RF-system and plasma loading. In order to match the impedance, it is essential to analyze the plasma impedance. In this study, we analyze the dependence of power transfer on the input parameters (frequency, input power and H2 gas pressure) by using the plasma impedance prediction model. The results indicate that in the case of frequency = 2 MHz, which is often used in the experiment, efficient power supply is seen in the wide range of input power and H2 gas pressure. Also, if the optimum value of input power and H2 gas pressure is input, it may be possible to reduce the influence of the frequency value on the power reflection efficiency.

Keywords

negative ion source, RF plasma, plasma impedance, impedance mathing, equivalent circuit model, parameter survey

DOI: 10.1585/pfr.14.3401094

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