Cherenkov diffraction radiation in beam diagnostics - investigation of a potential tool for FCC-ee

In recent years the investigation of Cherenkov diffraction radiation produced by charged particles passing in close vicinity of dielectric material led to promising prototypes for beam diagnostics. In this report, we present a simulation approach to investigate the radiated energy spectrum from Cherenkov diffraction radiation of a single particle and a particle bunch with a focus on its exploitation for the Future Circular Collider for electrons and positrons (FCC-ee). The radiated energy spectra of a single particle from two analytical models that describe a flat and a cylindrical radiator geometry respectively are discussed. Different radiation regimes are characterized within the various spectra and their dependency on key beam parameters is evaluated. Proceeding with the radiated energy spectrum of a bunch of particles, the formation of a coherent and an incoherent radiation regime is demonstrated. As both regimes have their distinct characteristics, the analysis is split into two parts for the radiated energy spectra of the different bunch profiles at FCC-ee. For incoherent photons emitted in the visible spectrum, the application of a beam position monitor, as well as the bunch-by-bunch measurement of the longitudinal bunch profile over several turns are investigated. For coherent radiation emitted in the multi GHz range, the application of a beam position monitor operating with bandpass filters and a bunch length measurement relying on power measurements at different frequencies are discussed. All these applications could profit from the unique characteristics of Cherenkov diffraction radiation. Its high directivity would allow to minimize background contribution and as it is a non-invasive technique it has minimal impact on the accelerated particles, which makes it a perfect candidate for future beam instru- mentation devices.