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For the accelerator-based future of high energy physics at the energy frontier, CERN started to investigate a 92 km circumference Future Circular Collider (FCC), as e⁺/e⁻ collider the FCC-ee will operate at beam energies up to 182.5 GeV. Beside the machine operational aspects, beam instrumentation will play a key role in verifying and optimizing the machine to achieve the ambitious beam parameters and quality. This paper gives a brief overview of the various challenges to develop the required beam instruments, with focus on beam position, beam size and bunch length measurements, and well as an outline of the planned R activities., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

In recent years the potential of using Cherenkov Diffraction Radiation (ChDR) as a tool for non-invasive beam diagnostics has been thoroughly investigated. Although several theoretical models of ChDR have been developed, differences in their assumptions result in inconsistent predictions. The experimental verification is therefore needed in order to fully understand ranges of validity of available models. In this contribution we present a detailed theoretical study of the radiation yield as a function of the beam-radiator distance. Following identification of beam parameters and frequency range for which differences between the model predictions are most prominent, we compare theoretical estimates with the results of a dedicated experiment., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

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.

In recent years Cherenkov Diffraction Radiation (ChDR) has been reported as a phenomenon suitable for various types of particle accelerator diagnostics. As it would typically work best for highly relativistic beam, past studies and experiments have been mostly focusing on the lepton machines. This contribution investigates the prospects on the utilization of ChDR as a diagnostic tool for the Large Hadron Collider (LHC). Based on theoretical considerations and simulation results we estimate the properties of the expected radiation, both in the incoherent and coherent domain, and we compare them with the requirements of the existing diagnostic systems. We also address the potential problem of the use of dielectric radiators in circular machines, where secondary electrons could potentially lead to the creation of electron clouds inside the beam pipe that may affect the radiator., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

When a relativistic charged particle travels at a short distance from the surface of dielectric material Cherenkov Diffraction Radiation (ChDR) is produced inside the dielectric. Recent observation of incoherent ChDR in the visible spectrum has opened the possibility of using this radiation for non-invasive beam size and position measurements. An experimental test to study this technique for highly directional beam position measurement has been initiated on the CLEAR facility at CERN, whilst another experimental investigation is underway at the Accelerator Test Facility 2 (ATF2) at KEK, Japan, to measure the resolution limit of ChDR for beam imaging diagnostics. This contribution presents the latest experimental results from both of these test facilities., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia