A High-Power Multi-Beam Klystron

70025 The pending upgrade at the Thomas Jefferson National Accelerator Facility requires a unique klystron that can be tuned specifically to individual superconducting accelerating cavities. This klystron must operate efficiently and stably in the linear gain region within a band of frequencies as well as when the electron gun control electrode voltage changes the beam perveance. This project will design and develop a multi-beam klystron that will operate from 1.492 to 1.502 GHz; have 1.5 dB beam current regulation and corresponding 13 to 9 kW output power with efficiency over 70%; have 40 dB amplification; operate stably even at output power 3 dB below saturation; have high voltage less than 10 kV; weigh less than 45 kg including the permanent magnet focusing system; and have a lifetime exceeding 20,000 hours. Phase I will produce a klystron design that includes a multi-cathode variable perveance electron gun, a periodic permanent magnet focusing system, collector geometry, a cavity system efficient at variable beam currents, a cooling system, and a power supply. The final report will have drawings from which a prototype klystron can be constructed in Phase II as well as data that support the design decisions. Commercial Applications and Other Benefits as described by the awardee: The proposed klystron should enjoy commercial success in driving particle accelerator superconducting cavities (e.g., the TJNAF upgrade); radio-frequency heating of materials; and other applications requiring output power up to ~30 kW, which can be attained with no essential change in design or efficiency.