FCC-ee Pre-Booster Accelerators

CERN’s ambitious new project, Future Circular Collider-ee, will have four operations as Z, W, H, and tt factories covering energies from 45.6 to 175 GeV. The main challenge of Z-operation is to achieve currents as high as 1450 mA; this will depend heavily on the injector. For this reason, we conclude that we need a high bunch charge of 3.3 × 1010, for both e− and e+, and fill 91 500 of each of those bunches into the collider. To achieve the goal, we have designed an S-band (2.856 GHz) normal conducting electron linac up to 6 GeV, which we will use to create and accelerate both electrons and positrons. Positrons will be created inside the linac at 4.46 GeV, will be accelerated up to 1.54 GeV at the linac, and will then be transferred to the designed damping ring. In this paper, we present the designed linac, damping ring, and the operational requirements of the 100 km booster.