Development of a high-power magnicon amplifier at 11.424 GHz

Summary form only given, as follows. The magnicon is a deflection-modulated microwave amplifier tube that is being developed as a prototype rf source for the proposed TeV Next Linear Collider. We present a progress report on a new 11.424-GHz repetitively-pulsed magnicon using a thermionic electron gun that is being assembled at the naval research laboratory in a joint experiment with Omega-P, Inc. This new magnicon makes use of an advanced high-convergence pierce-type electron gun that was fabricated by Litton Electron Devices and is designed to produce a 500-keV, 210-A, 1.5-mm-diameter electron beam. The gun is driven by a 1-/spl mu/sec, 10-Hz modulator. A matching 7-kG, 20-cm-bore water-cooled magnet was fabricated for the experiment at the Budker Institute. Tests of the electron gun are scheduled to begin in January 1998, and will include measurements of beam diameter as a function of axial position using a set of movable graphite apertures. The magnicon circuit has been optimized for maximum output efficiency, and minimum surface rf fields. A circuit design has been developed with a predicted efficiency of 65%, yielding an output power of 68 MW and a gain of 62 dB. Test drive, deflection, and output cavities have been built and characterized by cold testing, and engineering is under way on a set of high vacuum, bakable cavities for the experiment. The first tests of the new magnicon design should take place during 1998.