Mega-Watt Planar Coaxial Aluminum Nitride Window for eRHIC

The Office of Nuclear Physics long range plans include allocation of resources to develop technology for a polarized electron-ion collider. Brookhaven National Lab proposes to develop an electron ring-ring design that requires high power RF couplers. Their present coupler design includes Beryllia windows. Beryllia presents safety concerns and added costs for handling.The material properties of Aluminum nitride, high thermal conductivity, low loss tangent, high dielectric strength, and good mechanical strength make it a good candidate for an RF window. Replacing the BeO windows (which have OSHA issues) with AlN would mitigate safety issues and developing a window for 650 kW would provide ample safety for the 500 kW requirement. In Phase I TJS Technologies will perform extensive RF, thermal and structural analysis to determine a 650 kW design using AlN as the window material. Tension in the outer surface of these windows limits their power. If required pre-stressing of the window is an option. TJS Technologies will begin with the present BNL window and coupler design to ensure easy integration into their SRF cavity design. At the end of Phase II TJS Technologies plans to deliver a power coupler with AlN windows to BNL for testing. Electron-Ion colliders throughout the world, future advanced light sources and other high brightness accelerator facilities that require high power couplers will benefit from this effort. At the end of Phase II TJS Technologies will have produced a replacement window and power coupler for BNL that will eliminate any safety concerns from Beryllia. The design will enable greater through power for the power industry decreasing costs for high power applications.