Improvement of voltage holding and high current beam acceleration by MeV accelerator for ITER NB

Journal Article · Mon Sep 26 00:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3637416· OSTI ID:21611690

Taniguchi, M; Kashiwagi, M; Inoue, T; Umeda, N; Watanabe, K; Tobari, H; Dairaku, M; Yamanaka, H; Tsuchida, K; Kojima, A; Hanada, M; Sakamoto, K ^[1]

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1. Japan Atomic Energy Agency, Naka Fusion Research Establishment, 801-1 Mukoyama, Naka, 311-0193 (Japan)

Voltage holding of -1 MV is an essential issue in development of a multi-aperture multi-grid (MAMuG) negative ion accelerator, of which target is to accelerate 200 A/m{sup 2} H{sup -} ion beam up to the energy of 1 MeV for several tens seconds. Review of voltage holding results ever obtained with various geometries of the accelerators showed that the voltage holding capability was about a half of designed value based on the experiment obtained from ideal small electrode. This is considered due to local electric field concentration in the accelerators, such as edge and steps between multi-aperture grids and its support structures. Based on the detailed investigation with electric field analysis, accelerator was modified to reduce the electric field concentration by reshaping the support structures and expanding the gap length between the grid supports. After the modifications, the accelerator succeeded in sustaining -1 MV for more than one hour in vacuum. Improvement of the voltage holding characteristics progressed the energy and current accelerated by the MeV accelerator. Up to 2010, beam parameters achieved by the MAMuG accelerator were increased to 879 keV, 0.36 A (157 A/m{sup 2}) at perveance matched condition and 937 keV, 0.33 A (144 A/m{sup 2}) slightly under perveance.

• OSTI ID: 21611690
• Journal Information: AIP Conference Proceedings, Vol. 1390, Issue 1; Conference: 2. international symposium on negative ions, beams and sources, Takayama City (Japan), 16-19 Nov 2010; Other Information: DOI: 10.1063/1.3637416; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
43 PARTICLE ACCELERATORS
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ELECTRIC POTENTIAL
ELECTROSTATIC ACCELERATORS
HYDROGEN IONS 1 MINUS
ION BEAMS
ITER TOKAMAK
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NEUTRAL ATOM BEAM INJECTION
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BEAMS
CHARGED PARTICLES
CLOSED PLASMA DEVICES
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HYDROGEN IONS
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THERMONUCLEAR DEVICES
THERMONUCLEAR REACTORS
TOKAMAK DEVICES
TOKAMAK TYPE REACTORS