Modified Magnicon For High-Gradient Accelerator R&D

The magnicon is a high-power microwave amplifier that achieves gain through a build-up in deflection angle of an electron beam passing through a cascade of cavities in a guiding magnetic field. Magnicons are in use in two US laboratories as sources of high-power microwaves, principally for use in development and testing of structures for a future high-gradient electron accelerator. Both magnicons suffer from limitations that have prevented them from achieving their full design parameters. In the case of the 34-GHz magnicon at Yale University, these limitations have been traced to design issues in the output cavity and to technological issues during the construction of the tube. This project proposes to improve performance of the Yale magnicon by substituting for its existing output cavity a new design. The new cavity would be shorter, have a lower quality factor, and would need to sustain weaker fields than the present cavity. Preliminary simulations show that the modified magnicon should operate with much greater reliability than the present tube, and should provide much higher peak power output, in longer pulses, and with a higher pulse repetition rate. Commercial applications and other benefits: This project is directed at improving a dedicated microwave amplifier used for accelerator research. However, lessons gained from implementing the design change proposed here could influence design of other high-power microwave devices, such as those used in military and civilian radars, and in communications.