A Design Study for Megawatt Class Waveguide Input Coupler for Synchrotron Light Source Superconducting Cavities

Modern synchrotrons are providing higher beam currents and demanding more RF power from the superconducting cavities. The maximum RF power available without beam is limited by the maximum power rating of the WR1800 waveguide RF ceramic window used in the fundamental power coupler. Operation at this maximum power limit is hampered by the fact that the specific value of power transmitted which produces the maximum temperature difference can vary significantly depending on the thickness of the anti-multipacting titanium nitride coating on the ceramic. We propose a Phase II pototyping effort to develop a new higher power RF window for use in waveguide input couplers for superconducting cavities. The aim of the design is to increase the power limit to the highest practical value, with a goal of 1 MW standing wave. In Phase II, a test article would be built at AES with conditioning and testing taking place with a 300 kW transmitter at Brookhaven National Laboratory. Commercial Applications and Other Benefits: A successful propotype could subsequently be installed into an existing cryo-module at NSLS-II as an upgrade. Five facilities around the world could have the same upgrades. Any waveguide feed used for other accelerator applications properly scaled for frequency.