Use of TW output structures for high peak power RF generators

The beam optics and electric field characteristics of several recently constructed TW structures are presented. These structures were designed to extract high levels of peak power from 11.4 GHz modulated, 500 to 1,000A electron beams using three different RF amplifier configurations having nominal beam energies of 3.0, 1.2 and 0.5 MeV, respectively. The adoption of multicell, high phase velocity Tw output circuits with unusually large beam apertures (> λ0/2) has been instrumental in avoiding electric field breakdown and beam interception in these short wavelength, high current RF generators. For beam energies in the range of 0. 45 to 1. 3 MeV and RF output peak power levels of 100 to 300 MW, varying impedance and tapered phase velocity structures were used to minimize debunching and to maintain near synchronous conditions during beam traversal of the continuous interaction output circuit. A concluding section discusses the design characteristics and performance of a new style 100 MW TW klystron specifically configured to operate in a small warm bore superconducting solenoid or a 4 double-prime ID water-cooled solenoid