High Current Cathodes Without A-K Gap Closure

Award Information
Agency: Department of Defense
Branch: Air Force
Contract: N/A
Agency Tracking Number: 20014
Amount: $429,998.00
Phase: Phase II
Program: SBIR
Awards Year: 1994
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
416 Washington St. Se, Albuquerque, NM, 87108
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Donald E. Voss, Ph.d.
 (505) 255-4201
Business Contact
Phone: () -
Research Institution
Development of high power microwave (HPM) sources for Air Force applications requires cathodes with long usable lifetimes, negligible anode-cathode (A-K) gap closure, reproducible functioning under high repetition pulsing, uniform current density, and negligible plasma/current production from nearby surfaces. Cathodes must maintain such stable electron beam output characteristics for > 1 nsec. We propose to meet these requirements in an extremely low cost, robust carbon cathode with a matrix of carbon fiber tufts as the emitting surface. Innovations to improve performance include: cesium iodide coating to reduce plasma gap closure and improve current density uniformity; an intermediate electrode to reduce unwanted plasma production from nearby surfaces and increase total current; increased carbon tuft surface density to produce more uniform current density and reduce explosive plasma production; and a ballast resistor array behind the fibers to prevent hot spots of current/plasma production. Cathodes will be produced utilizing these novel features and tested on a crowbarred Marx for 1-2 nsec pulses. Using a corona bushing to eliminate edge effects, 5-cm radius cathodes will be tested with 4-cm A-K gaps up to the 150-200 kV range. Gap closure rates, current density uniformity, and field stress applied to cathode will be determined, and configuration optimized for meeting target performance goals.

* Information listed above is at the time of submission. *

Agency Micro-sites

SBA logo
Department of Agriculture logo
Department of Commerce logo
Department of Defense logo
Department of Education logo
Department of Energy logo
Department of Health and Human Services logo
Department of Homeland Security logo
Department of Transportation logo
Environmental Protection Agency logo
National Aeronautics and Space Administration logo
National Science Foundation logo
US Flag An Official Website of the United States Government