Study of Collective Effects in the FCC-ee Collider

TL;DR

This paper evaluates the collective effects in the FCC-ee collider, analyzing beam coupling impedance, instability thresholds, and mitigation strategies to ensure high luminosity performance.

Contribution

It provides a detailed analysis of collective effects, including impedance and instability thresholds, for the FCC-ee collider design, which is crucial for its optimal operation.

Findings

Beam coupling impedance levels identified

Instability thresholds estimated

Mitigation strategies discussed

Abstract

The Future Circular Collider (FCC) study aims at designing different options of a post-LHC collider. The high luminosity electron-positron collider FCC-ee based on the crab waist concept is considered as an intermediate step on the way towards FCC-hh, a 100 TeV hadron collider using the same tunnel of about 100 km. Due to a high intensity of circulating beams the impact of collective effects on FCC-ee performance has to be carefully analyzed. In this paper we evaluate beam coupling impedance of the FCC-ee vacuum chamber, estimate thresholds and rise times of eventual single- and multibunch beam instabilities and discuss possible measures to mitigate them.