Higher order modes driven by 2-cell superconducting cavities

This paper presents the design of 2-cell Tesla type cavity and the properties of higher order modes (HOMs) of 2-cell cavity simulated by HFSS process, including the tuning frequency, the quality factor, the shunt impedance and the distribution of the electronic fields. The simulation results of π mode using HFSS is the same as that using Superfish. The effect of HOMs on electron acceleration is analyzed. The analysis result shows that the efficiency of acceleration is decreased and the electron beam becomes unstable because of the HOMs.