High Current Density High Repetition Rate Ferroelectric Cathode

150 High Current Density High Repetition Rate Ferroelectric Cathode--FM Technologies, Inc., 10529-B Braddock Road, Fairfax, VA 22032-2236; (703) 425-5111 Dr. L.K. Len, Principal Investigator Dr. Frederick M. Mako, Business Official DOE Grant No. DE-FG02-97ER82376 Amount: $75,000 Aside from thermionic emission, previous methods of high-current-density electron emission for charged-particle accelerators require high extraction potentials or high-power lasers in order to extract electrons from a surface. Thermionic emitters, however, are lifetime limited when used to generate high-current-density electron beams. A solution to this problem would be a new electron source employing ferroelectric materials to generate a high-brightness, high-current density electron beam for high-power microwave devices such as klystrons and gyrotrons and for use as an injector for charged-particle accelerators. No high extraction fields, high power lasers, or high power heater supplies would be necessary. This project will extend current ferroelectric cathode technology so that a high-voltage, high repetition-rate, and long-pulse electron gun can be designed and used primarily for Stanford Linear Accelerator Center klystron gun applications. A practical electron gun will be designed that has a current density of 30 amperes per square centimeter, a 200 hertz repetition rate, and a 1-2 microsecond pulse length capable of being operated at up to 500 kilovolts. In Phase I, the ferroelectric materials will be selected, and the effects of space charge, focusing, cathode poisoning, cathode heating, and plasma formation on the source will be studied. A conceptual design of a gun system suitable for klystron applications at the Stanford Linear Accelerator Center will be developed. Detailed design, fabrication, and operation of the gun system will be conducted in Phase II. Commercial Applications and Other Benefits as described by the awardee: If successful, this high-current density, high repetition-rate, long-pulse electron gun should be suitable for microwave generation and high-brightness electron sources for accelerators. It should also be suitable for commercial and research electron beam applications, including further industrial development of cathodes for pseudospark switches and ferroelectric cathodes for flat screen displays._