Broadband high power rf window design for the BNL Electron Ion Collider

Abstract

Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility are collaborating on the design and construction of the next Electron Ion Collider (EIC) to be built at BNL. The EIC is a unique high-energy, high-luminosity, polarized electron-proton/ion collider. The EIC accelerator complex needs about 10 new rf and SRF systems with frequencies spanning 24 MHz to 1773 MHz, requiring more than 60 new high-power fundamental power couplers (FPCs). These couplers will operate in either pulsed mode or continuous wave mode with peak traveling wave power ranging from 10 s to 380 kW. Here we present our design for a 1-MW broadband rf window suitable for EIC rf and SRF systems with operating frequencies up to 591 MHz. This design takes advantage of the numerous synergies between the various rf and SRF systems to make it broadly applicable. The rf window design criteria are based on the requirement for the 591-MHz electron storage ring (ESR) SRF cavities, as it will operate at both the highest traveling wave power and the highest peak power over the EIC rf/SRF complex. The results presented will detail the FPC power requirement, rf window choices, design criteria, and multiphysics performance in the most critical application, the ESR SRF cavity, and how the rf window design applies to other EIC rf/SRF systems.