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 an d developed in the framework of the Frascati Phi-Factory project DA Ph i NE. The cavity high order modes (HOM) are the primary source of coup led-bunch instabilities in multibunch storage rings. The energy delive red by the particle beam to the cavity HOMs and coupled out with waveg uides is converted by BTHD into the TEM coaxial mode and dissipated by a 50 Omega load connected via a ceramic feedthrough. This article dea ls with the design and the low power tests performed an a BTHD prototy pe and the considerations for a real application to an accelerator.