High Power Diamond Cold Cathode

WE PROPOSE DEVELOPMENT OF HIGH PERFORMANCE COLD CATHODES BASED ON OUR RECENTLY INVENTED DIAMOND FIELD EMISSION THIN FILMS. THE DIAMOND COLD CATHODES OFFER HIGHER STABILITY, LARGER EMISSION SITE DENSITY, MUCH HIGHER LIFETIME THAN EXISTING COLD CATHODES. DIAMOND'S HIGHER THERMAL CONDUCTIVITY, HIGHER THERMAL DIFFUSIVITY AND LOWER SPUTTER YIELD DISCOURAGES THERMAL EVAPORATION OF EMISSION SITES, AND THUS REDUCES THE POSSIBILITY OF ANODE-CATHODE (A-K) GAP CLOSURE. IN ADDITION, DIAMOND NEGATIVE ELECTRON AFFINITY ALLOWS EXTREMELY HIGH CURRENTS (-1000A/sq. cm) CAN BE EMITTED AT LOW ELECTRIC FIELDS. THE CATHODE IS MADE OF AN AMORPHIC DIAMOND(TM) THIN FILM DEPOSITED BY LASER ION PLASMA METHOD, AND CONSISTS OF sp3 GRAINS ON THE ORDER OF A FEW HUNDRED TO FEW THOUSAND ANGSTROMS IN SIZE. EACH ONE OF THESE GRAINS CAN ACT AS AN ELECTRON EMISSION SITE, GIVING A VERY HIGH (-10E8/cm2) SITE DENSITY. THE CATHODE LIFETIME IS FURTHER INCREASED BECAUSE EACH SITE NOW NEEDS TO DELIVER VERY SMALL AMOUNT OF CURRENT. ADDITIONALLY, RELATIVELY HIGH LATERAL RESISTANCE OF DIAMOND FILM (IN THE PLANE PARALLEL TO THE FILM) ENSURES ADJACENT EMISSION SITE ISOLATION, WITHOUT DISSIPATING LARGE POWERS IN THE CATHODE. THESE CATHODES HAVE BEEN TESTED TO DELIVER A CONTINUOUS CURRENT DENSITY OF 10A/sq. cm WITHOUT ANY NOTICABLE DAMAGE TO THE CATHODE. IN PHASE I OF THIS PROJECT, WE WILL DETERMINE THE ELECTRIC FIELDS, CURRENT DENSITY AND USEFULNESS OF THIS TECHNOLOGY IN DIRECTED ENERGY WEAPONS.