Design of an electron source for the FCC-ee with top-up injection capability

Abstract

The Future Circular Collider (FCC) study at CERN aims for a 100 TeV range proton collider. As a first phase of the project, an electron–positron collider (FCC-ee) in the same tunnel with a large circumference of 90 km is investigated. A collaboration for the design of an injector-chain for such a machine has been set-up and financed by CHART (Swiss Accelerator Research and Technology Collaboration). This paper describes the design and optimization of the electron source, which has to provide electrons to the collider as well as for positron production. Due to strong collective effects in the collider the lifetime of the bunches is relatively short and the charge of colliding bunches needs to be very well-balanced. Therefore, a particular challenge for the electron source design is the requirement to be able to replenish individual bunches in the collider in a top-up injection mode almost continuously.