Comparison of velvet- and cesium iodide-coated carbon fiber cathodes

• Published in: IEEE transactions on plasma science Vol. 29; no. 3; pp. 445 - 451
• Main Authors: Shiffler, D., LaCour, M., Golby, K., Sena, M., Mithcell, M., Haworth, M., Hendricks, K., Spencer, T.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-06-2001; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Carbon dioxide; Carbon fibers; Cathodes; Cesium iodides; Comparative analysis; Diodes; Electric potential; Electricity; Electron beams; Electron tubes; Electronic tubes, masers; Electronics; Evolution; Exact sciences and technology; Explosives; Geometry; Microwave tubes (eg, klystrons, magnetrons, traveling-wave, backward-wave tubes, etc.); Microwaves; Reproducibility; Reproducibility of results; Surface impedance; Voltage; High power; Cathode; Electron beam; Microwave; Experimental study; Cesium iodide; Microwave tube; Carbon fiber; Beam currents
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/27.928942

Presents results of an experimental comparison of a velvet cathode- and a carbon fiber cathode-coated with cesium iodide (CsI) salt. Each cathode had a planar geometry, with similar emission areas. The cathodes were tested at electric field strengths of 50 kV/cm at anode-cathode (A-K) gaps of 4.0 cm. The applied voltage had a 1-/spl mu/s duration and the pulser was operated at up to a 1-Hz repetition rate. The system had a low base pressure (<1.0/spl times/10/sup -7/ torr). This paper reports the results and comparisons of experiments on each cathode. We address the current and voltage characteristics, the shot-to-shot reproducibility, the pressure evolution of the diode under 1-Hz operation, and the lifetime of the cathodes.