Preliminary design consideration for CEPC fast luminosity feedback system

Purpose Future large high-luminosity electron–positron colliders such as circular electron positron collider (CEPC) and future circular collider (FCC-ee) require nanometer-sized beams at the interaction point (IP). The luminosity is very sensitive to the beam orbit drifts at the IP. It is essential to have a fast luminosity feedback system at the IP to maintain optimum beam collision conditions and prevent a luminosity degradation due to orbit drifts in the presence of mechanical vibrations and dynamical imperfections.
Methods We considered two possible methods for this purpose for CEPC: one based on measurements of the luminosity and the other based on measurements of the beam orbits around the IP.
Results In this paper, we present the preliminary design consideration for a fast luminosity feedback system at the IP of CEPC.