Development of a 150 MW Periodic Permanent Magnet Focused X-Band Klystron Amplifier

165 Development of a 150 MW Periodic Permanent Magnet Focused X-Band Klystron Amplifier--MDS Company, 1955 Mountain Boulevard, Suite 101, Oakland, CA 94611-2830; (510) 339-0957 Dr. Patrick Ferguson, Principal Investigator Dr. Patrick Ferguson, Business Official DOE Grant No. DE-FG03-97ER82427 Amount: $75,000 The X-band Next Linear Collider proposed by SLAC is expected to require a large number of klystrons. However, the successful development of a high power klystron will greatly reduce the number required, resulting in a substantial cost savings. This project, in Phase I, will design an X-band klystron capable of generating a peak output power of 150 megawatts at 11.424 Ghz with a pulse length of 1.5 microseconds at a pulse repetition rate of 120 Hz, through the use of conservative analysis, computer simulation and radio frequency (RF) testing. The electron beam in this klystron will be focused by a periodic permanent magnet structure, in lieu of an electromagnet. An electron gun capable of generating a 660 kV - 536 A solid electron beam from a thermionic cathode operating in ultra high vacuum will be designed. An electromagnetic wave-electron beam interaction circuit with a minimum saturation gain of 60 dB and a minimum efficiency of 45% will also be designed using computer simulation. A multiple cavity capacitive-coupled extended interaction output circuit with significantly reduced voltage gradients capable of efficiently extracting fundamental RF power from the electron beam will be designed, analyzed, constructed and RF tested. A new double disc - nitrogen cooled RF vacuum window will also be developed and tested. High thermal capability, long life and robust construction will be emphasized. For Phase II, the mechanical design will be completed, the various subassemblies will be fabricated and RF tested , and a 150 MW X-band klystron will be assembled and tested. Commercial Applications and Other Benefits as described by the awardee: Anticipated results are the successful development of a 150 MW X-band efficient - high duty klystron. This klystron is a prime candidate for SLAC's X-band Next Linear Collider and for high gradient electron accelerators for commercial applications.