Electron Gun and Beam Collector for a FOR A 10-MW, 1.3-GHz, Low-Voltage, Multi-Beam Klystron

Design of a future electron-positron collider, the International Linear Collider ILC, relies upon the availability of a large number of efficient, reliable 10-MW, 1.3 GHz RF amplifiers. Existing prototype multi-beam klystrons (MBKs) for this application operate at relatively high voltage (117 KV), and are physically too large for vertical mounting in the collider tunnel. The complications attending high-voltage operation and horizontal mounting can increase the cost for ILC. The same complications can apply to the FNAL proton accelerator needed for Project X. A low-voltage MBK design has been created to meet the needs of ILC and Project X that operates at 60 kV, and that is about half the height of the existing prototypes. This is achieved by use of 24 separate beams arranged in four independent clusters, with immersion of the electron guns and RF circuit in a common magnetic field. This project is for the electron gun and beam collector for this MBK, while design of the RF cavity chain and magnetic circuit are supported under a parallel SBIR grant. Plans for engineering and fabrication of the complete MBK in Phase II are to be developed in collaboration with a high-power RF tube manufacturer. Conceptual design of the RF cavity chain and magnetic circuit for 10 MW and 2.5 MW low-voltage multi-beam klystrons were completed. A plan for engineering, fabrication, and testing of a prototype 2.5 MW tube was developed. Engineering and fabrication of a prototype 2.5 MW multi-beam klystron will be done, with testing up to an average power of 20 kW. Commercial applications and other benefits: Availability of a low-voltage, 2.5 MW and/or 10-MW, 1.3-GHz MBK for ILC and other accelerator applications can lower the overall cost of a future collider, and create a multi-million dollar market for a new class of high-power microwave amplifiers. Other applications of high-power MBKs can be found in industrial processing, adding to the commercial potential of this device.