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Conditioning of Carbon Fiber Cathodes in UHV-Sealed Tubes at 200 A/cm \(^{2}\).
- Source :
- IEEE Transactions on Plasma Science; Aug2014, Vol. 42 Issue 8, p2007-2014, 8p
- Publication Year :
- 2014
-
Abstract
- This paper presents a study on outgassing and electrical conditioning for three carbon fiber cathode types in a vacuum-sealed, high-power microwave virtual-cathode-oscillator (vircator) that operates in the low \(10^{-9}\) torr pressure regime. The three cathode types consist of a bare bimodal fiber structure, a bare unimodal fiber structure, and a cesium-iodide coated bimodal fiber structure with identical fiber coverage of 2% by area with a surface area of ∼20 cm \(^{2}\) . The electrodes are cleaned by a 1.2 kW, argon/oxygen microwave plasma prior to complete vircator assembly, followed by a 300 °C bake-out for 72 h. Each cathode was pulsed in a single pulse operation by an 80 J, low inductance Marx generator with an approximate pulsewidth of 100 ns full-width at half-maximum for 10 000 current pulses. The data presented includes individual gas constituents, high-speed intensified charge coupled device (ICCD) imaging, and voltage and current waveforms. The conditioning process resulted in a gas load reduction of ∼ 80% overall, with the indication that the bare bimodal fiber structure performed the best as diode power increased throughout the experiment, while the power decreased for the other tested cathode types. [ABSTRACT FROM PUBLISHER]
- Subjects :
- OUTGASSING
MASS transfer
CARBON fibers
CATHODES
CESIUM
Subjects
Details
- Language :
- English
- ISSN :
- 00933813
- Volume :
- 42
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- IEEE Transactions on Plasma Science
- Publication Type :
- Academic Journal
- Accession number :
- 97518734
- Full Text :
- https://doi.org/10.1109/TPS.2014.2329878