Design of Fundamental Power Coupler of 5 Cell Elliptical SRF Cavity Using CST Microwave Studio

A 5 cell elliptical cavity prototype has been build to accelerate the 100 MeV high beam of protons [1]. For cavity = 0.61 β g at 650 MHz in which the cavity structure is optimized by using the code from SUPERFISH [2]. The Q value of the cavity measured is 0.61x109 for 4.2 K. In the frequency range 2 – 5 GHz with CST MICROWAVE STUDIO [3]. It has been designed taking into account the advantages of both the waveguide type and coaxial type coupler This paper explains the current design of the cavity with a different angle of aperture and wall which have better mechanical stability and flatness, consisting of facilities for surface processing and less loss of beam. In this paper, the fundamental power coupler of a 5-cell 650MHz elliptical SRF cavity has been designed using CST MICROWAVE STUDIO. Here we have considered the ceramic window matching and co-axial to rectangular waveguide matching for the power coupler.