Compact Radio-Frequency Electron Gun

Microwave Technologies is proposing the development of a novel radio-frequency electron gun (CRFG) for applications such as high-power, high-frequency radiation sources for BMDO sensors and directed energy. The CRFG employs a radio-frequency (RF) electricfield produced inside a compact microwave resonator to extract short high-current electron bunches from a novel silicon cathode. The cathode under consideration is fabricated using solid-state microfabrication techniques and should offer order ofmagnitude improvements in size and power over state-of-the-art counterparts. Initial studies for an S-band rf electron gun show that the CRFG can deliver 35-60 picosecond-long electron bunches at 2.85 GHz with a peak current of 1 ampere and at an energyof 20 keV. The use of a reliable silicon cathode, in addition to its compactness, power efficiency and ruggedness, makes the CRFG ideal for airborne applications. Commercial applications of the CRFG include electron sources for the next generation ofmicrowave devices such as klystrons and traveling wave tubes for satellite communications. Another key application of the CRFG is as a source of very short electron bunches for medical and industrial electron accelerators. Phase I is aimed at an initialdc study of the CRFG cathode, design of the microwave cavity and waveguide coupling, as well as particle-in-cell computer studies to establish credible estimates of beam power, input power, efficiency, maximum current and other key parameters. The CRFGshould provide order of magnitude improvements in size and power over existing technologies by using a rugged silicon cathode which eliminates the need for heating elements and yields a high-current super-fast turn-on rf-driven electron source.The CRFG isa very compact, high-current electron gun that should be able to provide very narrow high-frequency electron bunches for a variety of applications. Of particular interest are electron accelerators and millimeter-wave sources for airborne radar, satellitecommunications, wireless communications, and the microwave power module.