Design of a Cavity Beam Position Monitor for the ARES Accelerator at DESY

The SINBAD facility (Short and INnovative Bunchesand Accelerators at DESY) is foreseen to host various experiments in the field of production of ultra-short electron bunches and novel high gradient acceleration techniques.The SINBAD linac, also called ARES (Accelerator ResearchExperiment at SINBAD), will be a conventional Sband linear RF accelerator allowing the production of low charge (within a range between 0.5 pC and 1000 pC) electron bunches. To detect the position of low charge bunches, a cavity beam position monitor is being designed based on the experience from the European XFEL. It will consist of a stainless steel body with a quality factor of 70, a resonance frequency of 3.3 GHz and a relative wide gap of 15mmto reach a high position sensitivity of 4.25 V/(nC mm) of the dipole resonator. The design considerations and simulation results of the dipole and reference resonator will be presented