FCC accelerator

The FCC-ee accelerator is developed in the framework of the FCC collaboration, currently including ~90 institutes.

Schematic of the FCC implantation
in the Geneva region

The design of the circular FCC accelerator, with a circumference of 80-100 km, covers options for hadron-hadron, electron-positron and electron-hadron collisions. The FCC-ee accelerator study foresees electron-positron collisions at ~350 GeV, 240 GeV, 161 GeV and 91 GeV. The luminosity performance of FCC-ee increases with decreasing centre-of-mass energy from 1.3 * 1034 cm-2 s-1 at 350 GeV to 90 * 1034 cm-2 s-1 at 91 GeV per interaction point. The baseline design currently foresees two interaction points.

The CERN SPS and LHC would serve as injectors to FCC. The main challenges of FCC-ee are the high levels synchrotron radiation (50 MW per beam), the  luminosity lifetime and the RF system requirements, which are very different for the four energy stages. At the highest centre-of-mass energy of 350 GeV, the energy loss per turn amounts to 7.5 GeV. The FCC-ee design foresees two separate rings for electrons and positrons. FCC-ee will be equipped with a top-up booster for permanent beam injection.

The study of the FCC-ee accelerator draws on experiences with high-luminosity flavour physics facilities.