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Explosive emission cathodes for high power microwave devices: gas evolution studies

Approved for public release, distribution is unlimited / Present-day high power microwave devices suffer from a lack of reliable, reproducible cathodes for generating the requisite GW-level electron beam in a vacuum. Standard explosive emission cathode pulse durations have been limited to 10's or 100's of ns due to the expansion of cathode-generated plasma and the ensuing impedance collapse that debilitates microwave output. Traditional thermionic cathodes do not suffer from this drawback of plasma generation, but have not yet been able to provide the required emission current densities explosive emission cathodes are capable of. It is expected that if the plasma could be made cooler and less dense, explosive emission would be more stable. Cesium iodide (CsI) has been found to slow the impedance collapse in many explosive emission cathodes. Herein we will experimentally examine diode impedance collapse, gas production, and cathode conditioning in an effort to perform an evaluation of explosive cathode performance in a typical thermionic electron gun environment. These results will then be used to help demarcate the parameter space over which these CsI-coated carbon fiber cathodes are viable candidates for the electron beam source in next-generation high power microwave devices. / Lieutenant, United States Navy

Identiferoai:union.ndltd.org:nps.edu/oai:calhoun.nps.edu:10945/1470
Date06 1900
CreatorsSchlise, Charles A.
ContributorsUmstattd, R. J., Book, D. L., Naval Postgraduate School (U.S.)., Department of Physics
PublisherMonterey, California. Naval Postgraduate School
Source SetsNaval Postgraduate School
Detected LanguageEnglish
TypeThesis
Formatxii, 43 p. : ill. (chiefly col.), application/pdf
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted.

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