Powerful Triaxial Klystron for X-Band and Beyond

50737-98-I Powerful Triaxial Klystron for X-Band and Beyond--Mission Research Corporation, 735 State Street, P.O. Drawer 719, Santa Barbara, CA 93101-3351; (805) 963-8761 Dr. John A. Pasour, Principal Investigator Mr. Scot R. Fries, Business Official DOE Grant No. DE-FG03-98ER82621 Amount: $74,991 The next generation of radio-frequency particle colliders will require enormous amounts of microwave power, on the order of one trillion watts total, at a frequency at least four times higher than existing accelerators. If scaled versions of existing klystrons were used to drive such an accelerator, almost 10,000 individual tubes would be required at a cost of hundreds of millions of dollars. However, these klystrons also would not be suitable for operation at the even higher frequencies envisioned for future generations of accelerators. This project will develop a new microwave source, the Triaxial Klystron Amplifier, that uses a large-diameter annular electron beam propagating between two coaxial structures. The Triaxial Klyston promises to be capable of an order of magnitude higher power and much higher frequency than scaled klystrons, while simultaneously achieving the high efficiency, phase stability, reliability, and repetitive operation required. This would greatly reduce the cost of future colliders and potentially provide the key to the economic viability of such accelerators. During Phase I, the overall cavity structure will be designed to maximize microwave power, and computer simulations of the beam interaction with the structure will be performed. The feasibility of the Triaxial Klystron will be determined by analyzing key engineering issues, such as repetitive electron beam generation and output coupling of the microwave power. The project will also investigate the potential scaling of the device to even higher frequencies as well as a novel, compact accelerator based on the Triaxial Klystron. The results of these analyses will be used to design an overall system that can be fabricated and tested during Phase II. Commercial Applications and Other Benefits as described by the awardee: The proposed work will demonstrate unequivocally the ability of the Triaxial Klystron Amplifier to satisfy the stringent conditions placed upon advanced linear accelerator drivers. The commercial market for this single application is huge. Other potential civilian applications include chemical processing, materials studies, bulk heating, surface processing, and plasma heating. The source can also play a major role in various military applications, such as electronic warfare and various nonlethal munitions._