A BROAD-BAND WAVE-GUIDE TO COAXIAL TRANSITION FOR HIGH-ORDER MODE DAMPING IN PARTICLE ACCELERATOR RF CAVITIES

A novel Broadband Waveguide to Coaxial Transition for High Order Mode Damping in Particle Accelerator RF Cavities (BTHD) has been studied and developed in the framework of the Frascati Phi-Factory project DA Phi NE. The cavity high order modes (HOM) are the primary source of coupled-bunch instabilities in multibunch storage rings. The energy delivered by the particle beam to the cavity HOMs and coupled out with waveguides is converted by BTHD into the TEM coaxial mode and dissipated by a 50 Omega load connected via a ceramic feedthrough. This article deals with the design and the low power tests performed an a BTHD prototype and the considerations for a real application to an accelerator.