The SPS and an Alternative Ring Design as Pre-Booster of FCC e(+)e(-) Injector

The FCC-e(+)e(-) injector complex needs to produce and to transport a high-intensity e(+)/e(-) beam at a fast repetition rate for topping up the collider at its collision energy. Two different options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and a completely new ring. The purpose of this paper is to present the necessary modifications of the existing SPS which is mainly adding damping and Robinson wigglers to reach the required emittance for SPS and the updates on conceptual design of an alternative accelerator ring with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the main parameters of both choices are established, including the optics design and layout updates.