Efficient, 100-160 MW, X- and Ku-band gyroklystron amplifier designs for linear colliders

Summary form only given. Efficient, 100-160 MW, X- and Ku-band microwave sources with pulse-lengths of 1 /spl mu/s are being developed for driving future linear colliders. Two-cavity and three-cavity, co-axial designs of relativistic gyroklystron amplifiers are presented which fulfill these requirements. Simulations are carried out using the existing set of codes which includes a scattering matrix code for cold-cavity fields, a linear start-oscillation code for stability, and a nonlinear gyroklystron code for optimizing parameters to get maximum efficiency and gain. The cavities are designed to have high mode purity, good inter-cavity isolation, and stability to the excitation of the spurious modes. The quality factors of the cavities, the lengths of the drift sections, and the magnetic field profile are optimized for each design. During this study, the effect of velocity spread in the beam on the efficiency of the device is taken into account. In addition, HFSS code is used to study the effect of dielectric loading and power losses in the cavity.