Development of a High Gain, High Power Traveling Wave Relativistic Klystron

75016S Relativistic klystrons, presently under development for linear collider applications, and existing high-power pulsed klystrons, used to energize research linear accelerators, typically have amplification factors (gain) between 45 and 55 dB. These klystrons generally require pulsed vacuum tube drivers to supply input power levels up to several hundred watts. However, for applications in which a 20 dB klystron gain would be sufficient, these relatively complex vacuum-tube driver systems could be replaced by small, low power, solid state sources, resulting in considerable simplification and cost savings. This project will develop technology leading to stable, high gain (>70 dB), high efficiency (>50 percent) klystron performance. During Phase I, phase orbit characteristics were analyzed and microwave parameters were established for an asynchronously operated, tapered phase velocity, traveling wave output structure designed for a 17 gigahertz relativistic klystron. To prevent parasitic oscillations, special suppression circuits were designed and configured for contiguous assembly with the high-gain-klystron, dual-feed-racetrack, output coupler. Phase II will be directed at engineering and fabricating the traveling wave tapered phase velocity, high gain dual feed output structure, parasitic oscillation suppression circuits, and the associated evacuated rectangular waveguide components. In addition, the new high-gain-klystron and waveguide components will be assembled; and the system will be tested to evaluate the stability, efficiency and gain of the high power 17 gigahertz klystron. Commercial Applications and Other Benefits as described by the awardee: The availability of stable, high gain klystron amplifiers should enable existing complex driver systems and associated pulsed helix and filament power supplies to be replaced by low power, simple solid state amplifiers.