EXISTING CATHODE TECHNOLOGY CANNOT PROVIDE THE COMBINATION OF HIGH AVERAGE CURRENT DENSITY AND LONG LIFE THAT IS ESSENTIAL FOR HIGH AVERAGE POWER ACCELERATOR APPLICATIONS.

EXISTING CATHODE TECHNOLOGY CANNOT PROVIDE THE COMBINATION OF HIGH AVERAGE CURRENT DENSITY AND LONG LIFE THAT IS ESSENTIAL FOR HIGH AVERAGE POWER ACCELERATOR APPLICATIONS. THESE APPLICATIONS INCLUDE HIGH POWER LASERS, HIGH POWER MICROWAVE GENERATORS, CHARGED PARTICLE BEAM CONCEPTS AND RADIATION PROCESSING. THE CONTROLLED POROSITY DISPENSER (CPD) CATHODE IS A NEW TYPE OF THERMIONIC EMITTER WHICH HAS ENORMOUS POTENTIAL TO MEET THESE CRITICAL NEEDS. THIS IS BASED ON THE PROJECTED CAPABILITIES TO PROVIDE HIGH, REPETITIVELY PULSED CURRENT DENSITY (>100 A/CM SQ) AND LARGE EMISSION AREA (>100 CM SQ) WITH LONG LIFE (>10(9) PULSES) AND LOW SENSITIVITY TO POISONING. THE CPD IS A BARIUM DISPENDER-TYPE CATHODE IN WHICH THE NONUNIFORM POROUS TUNGSTEN MATRIX IS REPLACED WITH A TUNGSTEN FOIL CONTAINING SMALL, PRECISELY FORMED PORES. THE UNIFORM PORE SIZE AND SPACING COMBINED WITH THE LOW IMPEDANCE TO FLOW OF BARIUM FROM ITS RESERVOIR TO THE EMITTING SURFACE GIVES THIS CATHODE ITS ATTRACTIVE FEATURES WHICH PROVIDE ORDER-OF-MAGNITUDE IMPROVEMENT IN EMITTER PERFORMANCE. THE PROPOSED EFFORT WILL DEVELOP SCALABLE (CPD) CATHODE DESIGNS AND DEMONSTRATE THE FEASIBILITY OF OPERATION AT HIGH CURRENT DENSITIES IN REPETITIVELY PULSED SYSTEMS.