Initial boronization of the DIII--D tokamak

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States)

DOI:https://doi.org/10.1116/1.578235· OSTI ID:7284876

Phillips, J; Hodapp, T; Holtrop, K; Jackson, G L ^[1]; Moyer, R ^[2]; Watkins, J ^[3]; Winter, J ^[4]

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1. General Atomics, P.O. Box 85608, San Diego, California 92186-9784 (United States)
2. University of California, Los Angeles, Los Angeles, California 90024-1597 (United States)
3. Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States)
4. Institute of Plasmaphysics, Research Centre Juelich GmbH, Association Euratom/Kernforschungsanlage, P.O. Box 1913, Juelich (Germany)

A system has been installed to deposit a thin film of elemental boron on the walls of the DIII--D tokamak, in order to reduce the influx of impurities during plasma discharges. Subsequently new regimes of substantially improved tokamak energy confinement were obtained. The deposition of the boron layer is achieved during a glow-discharge session using a helium-diborane gas mixture and a film of {approx}100 nm is deposited. The boronization system includes special storage and handling precautions for the diborane, a delivery and metering system for the glow discharge, modifications to the tokamak's residual gas analyzer system, and a dedicated system for handling and neutralizing the exhaust gas from the tokamak. Tokamak discharges with similar parameters before and after boronization are used to characterize the effects of the boron film. Nickel has been reduced by a factor of 30, while impurities such as oxygen and carbon are reduced fivefold. A system of pulsing the glow discharge has been developed in order to improve the uniformity of the film applied

• DOE Contract Number: AC03-89ER51114
• OSTI ID: 7284876
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States) Vol. 10:4; ISSN JVTAD; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700420* -- Fusion Technology-- Plasma-Facing Components-- (1992-)
BORON
BORON COMPOUNDS
CLOSED PLASMA DEVICES
COATINGS
DEPOSITION
DEUTERIDES
DEUTERIUM COMPOUNDS
ELECTRIC DISCHARGES
ELEMENTS
GLOW DISCHARGES
HYDROGEN COMPOUNDS
IMPURITIES
PLASMA IMPURITIES
PROTECTIVE COATINGS
SEMIMETALS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES