Klystron Amplifier Utilizing Scandate Cathode and Electrostatic Focusing

We propose to build an electrostatically focused klystron that exploits recent breakthroughs in scandate cathode technology. We have built cathodes with greater than 100 Amps/cm2 emission. This project offers an opportunity to test those cathodes in real world devices. Because of their small size (.050 inch diameter) and low power dissipation (under 1.2 watts), they are ideal for long-range space missions. Also, their low beam convergence makes electrostatic focusing feasible. This, in turn, provides a dramatic reduction in amplifier size and mass. Without magnets, traveling wave tubes and klystrons will be lighter and smaller, a further enhancement for space missions. Phase I develops cathodes, pierce guns and focusing stacks. Phase II will see construction of a working klystron or TWT. Scandate cathodes also provide longer life than conventional cathodes. Their small size allows amplifiers to reach much higher frequencies, bandwidth, and data rates than current art.

Scandate cathodes would improve performance and life on all NASA vacuum linear beam amplifiers and sources. They would allow higher data rates, higher frequencies and more power. They could be used in ion thrusters for discharge and neutralization, both for near-earth and long-range space flights. Their small size and high loading make them essential in terahertz amplifiers and sources. NASA is interested in terahertz for upper atmosphere studies, as well as communications.

There is a shortage of bandwidth and number of channels in commercial wireless networks. Scandate cathodes address this by raising the frequency and power of traveling wave tubes. This is particularly true of geocentric communications satellites. Also, their longer life will reduce maintenance costs on these systems. Eventually, scandate cathodes will be used in earth-based communications networks, where the same issues arise, although not as acutely. Scandate cathodes are also needed in micro-focus x-ray guns and in UV electron-beam-pumped lasers.

This is early/mid-stage (TRL 4) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

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