Multilayer vacuum window for wide-band microwave plasma diagnostic systems

Journal Article · Sun Oct 15 04:00:00 EDT 2006 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.2229269· OSTI ID:20861287

Cavazzana, Roberto; Moresco, Maurizio ^[1]

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1. Consorzio RFX-Associazione EURATOM-ENEA, Corso Stati Uniti 4, Padova 35127 (Italy)

Microwave diagnostics, e.g., reflectometry and electron cyclotron emission in plasma machines, often require large windows displaying low attenuation and reflection on a wide band, in addition to some basic features such as vacuum tightness and mechanical robustness. Wide-band matching is usually achieved by coating the window with dielectric layers of suitable permittivity and thickness. On the vacuum side the coating must also be vacuum compatible and resistant to the thermal radiation coming from plasma. On the RFX machine, to satisfy these requirements, a boron nitride disk properly machined on the surface facing the plasma has been clamped to the existing fused silica window. The addition of a Teflon layer on the air side allowed to attain power reflection coefficients as low as 0.025 in the frequency ranges of 26.5-40, 40-56, and 56-75 GHz and as low as 0.01 in the frequency ranges of 75-92 and 92-110 GHz.

• OSTI ID: 20861287
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 77; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BORON NITRIDES
DIELECTRIC MATERIALS
GHZ RANGE
LAYERS
MICROWAVE RADIATION
PERMITTIVITY
PLASMA
PLASMA DIAGNOSTICS
REFLECTION
REVERSE-FIELD PINCH
REVERSED-FIELD PINCH DEVICES
TEFLON
THERMAL RADIATION
THICKNESS
WALL EFFECTS