Design of the X-band cavity beam position monitor

The free-electron laser (FEL) is a fourth-generation light source producing coherent X-rays by using an interaction between the electromagnetic field and the electron bunch. Producing coherent X-rays requires sub-micron beam alignment in the undulator section of the FEL. The cavity beam position monitor (BPM), as a non-destructive diagnostics tool, can provide sub-micron resolution in the beam position reading. In this research, an X-band cavity BPM were modelled and simulated. The RF properties and the signal response of the cavity BPM were calculated by using an electromagnetic field simulation program (CST Studio Suite).