Design of inductively detuned RF extraction cavities for the Relativistic Klystron Two Beam Accelerator

An inductively detuned traveling wave cavity for the Relativistic Klystron Two Beam Accelerator expected to extract high RF power at 11.424 GHz for the 1 TeV Center of Mass Next Linear Collider has been designed. Longitudinal beam dynamics studies led to the following requirements on cavity design: (a) Extraction of 360 MW of RF power with RF component of the current being 1.15 kAmps at 11.424 GHz (b) Inductively detuned traveling wave cavity with wave phase velocity equal to 4/3 the speed of light. (c) Output cavity with appropriate Q_ext and eigenfrequency for proper matching. Furthermore, transverse beam dynamics require low shunt impedances to avoid the beam break-up instability. We describe the design effort to meet these criteria based on frequency-domain and time-domain computations using 2D- and 3D-electromagnetic codes