Microwave and accelerator research. Final report on Grant DE-FG02-92ER40731

Abstract

This report summarizes the main technical objectives and accomplishments during the life of the grant, and concludes with data on publications describing the research. The main activity was the development of very high power microwave sources, initially in X-band, and recent initial work on a Ka band TWT amplifier. There was additional activity on ferroelectric emitters. Highlights include the following: (1) The development of a relatively broad band microwave source yielding approx. 75 MW power at a power efficiency of 54% and an energy conversion efficiency of 43%. (2) The development of a ferroelectric cathode electron gun which yielded a beam current of up to 350 A at 500 kV. The device was shown to operate satisfactorily at a low repetition rate, limited by the available power supplies. The final beam power obtained exceeds that achieved elsewhere by several orders of magnitude. The gun development achieved was shown to give an electron beam suitable for high power X-band microwave sources with the demonstration of a 5-MW tunable X-band TWT single-stage amplifier. (3) Work was initiated on a Ka-Band TWT amplifier. Gains of over 30 dB were achieved at peak output powers of about 4 MW. Appendices include two submitted papers: Symmetric and asymmetric mode interaction in high-power traveling wave amplifiers: experiments and theory and High power microwave generation using a ferroelectric cathode electron gun.