We describe the design and functionality of an RF directional coupler for which the power division between the output ports is mechanically variable. In an alternate power distribution scheme for the ILC, power is delivered to cavities in pairs, through hybrids. Four pairs, or eight cavities, are fed from one waveguide feed, from which one fourth, one third, and one half of the power is coupled...

The superconducting XFEL machine will be built in a single tunnel. The RF stations provide RF power of up to 10 MW at 1.3 GHz. The modulators will produce high-voltage pulses of up to 120 kV, 140 A with a pulse length of 1.54 ms. These will be installed in a service hall at ground level. The klystrons will be positioned near the cavities inside of the tunnel. The energy will be transported via ...

V-band Klystrons find applications in satellite communications and 5G technology. Here, we present a Klystron using radial re-entrant square cavities (RRSCs). The RRSCs are easy to fabricate, assemble, align, tune the operating frequency, which significant concerns V-band. We have optimized number of gap for best possible gain bandwidth. eigenmode particle-in-cell (PIC) simulation results CST m...

The azimuthally invariant cold-fluid equilibrium is obtained for a periodic, strongly bunched charged annular beam with an arbitrary radial density profile inside of a perfectly conducting cylinder and an externally applied uniform magnetic field. The selfelectric and self-magnetic fields, which are utilized in the equilibrium solution, are computed self-consistently using an electrostatic Gree...

The RF system for the SNS superconducting linac consists of a superconducting cavity, a klystron, and a low-level RF (LLRF) control system. For a proton linac like SNS, the field in each individual cavity needs to be controlled to meet the overall system requirements. The purpose of the LLRF control system is to maintain the RF cavity field to a desired magnitude and phase by controlling the kl...