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High Current Cathodes Without A-K Gap Closure

Award Information

Department of Defense
Air Force
Award ID:
Program Year/Program:
1994 / SBIR
Agency Tracking Number:
Solicitation Year:
Solicitation Topic Code:
Solicitation Number:
Small Business Information
Voss Scientific, LLC
418 Washington Street, SE Albuquerque, NM -
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Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Phase 2
Fiscal Year: 1994
Title: High Current Cathodes Without A-K Gap Closure
Agency / Branch: DOD / USAF
Contract: N/A
Award Amount: $429,998.00


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.

Principal Investigator:

Donald E. Voss, Ph.d.

Business Contact:

Small Business Information at Submission:

Voss Scientific
416 Washington St. Se Albuquerque, NM 87108

Number of Employees:
Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No