Surface modification of the PLT lower hybrid waveguides to improve operations

Journal Article · Thu Apr 01 00:00:00 EST 1982 · J. Vac. Sci. Technol.; (United States)

DOI:https://doi.org/10.1116/1.571568· OSTI ID:5419740

Timberlake, J; Cohen, S A; Crider, C; Estepp, G; Hooke, W; Manos, D; Stevens, J; Ulrickson, M

Arrays of waveguides for use in PLT during lower hybrid wave heating and current drive experiments have been treated to improve resistance to high power rf breakdown. The breakdown, which even after extensive conditioning of stainless steel waveguides occurs at power levels of > or approx. =1 kW/cm/sup 2/, has been attributed to gas evolved from waveguide walls, electron multipacting, photoelectron emission and/or arcing. A waveguide treatment program has been developed to reduce each of these effects. Mechanical polishing of the waveguide, by means of a unique polishing jig, removes surface protrusions of > or =0.001 in. Electrochemical polishing is then used to remove imbedded polishing grit and reduce surface roughness, thereby reducing the surface area for adsorbed gases. Ultrasonic cleaning in hot Alconox removes the residue. The interior of the waveguide array is then coated with glyptal or by electrophoretic deposition of carbon lamp black suspended in a glyptal/xylene solution. The resultant 1--5-..mu..-thick film is vacuum pyrolyzed to carbon. These carbon coatings are highly adherent and have the desired properties of low gas sorption. A treated waveguide array has been operated successfully on a test stand and another in PLT.

• Research Organization: Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08544
• DOE Contract Number: AC02-76-CH03073
• OSTI ID: 5419740
• Journal Information: J. Vac. Sci. Technol.; (United States), Vol. 20:4
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CARBON
ELECTRODEPOSITION
CARBON BLACK
PLT DEVICES
WAVEGUIDES
BREAKDOWN
ELECTRODEPOSITED COATINGS
ELECTROPOLISHING
MECHANICAL POLISHING
PERFORMANCE TESTING
ADHESION
ADSORPTION
PLASMA HEATING
RF SYSTEMS
ROUGHNESS
SCANNING ELECTRON MICROSCOPY
STAINLESS STEELS
SURFACE CLEANING
WALLS
ALLOYS
CHROMIUM ALLOYS
CLEANING
COATINGS
CORROSION RESISTANT ALLOYS
DEPOSITION
ELECTROLYSIS
ELECTRON MICROSCOPY
ELEMENTS
HEATING
IRON ALLOYS
IRON BASE ALLOYS
LYSIS
MICROSCOPY
NONMETALS
POLISHING
SORPTION
STEELS
SURFACE COATING
SURFACE FINISHING
SURFACE PROPERTIES
TESTING
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production