Superconducting RF at CERN: Operation, Projects, and R&D

The CERN SRF infrastructure was originally set up for Nb on Cu-coated cavities for large electron positron collider (LEP) and later for large hadron collider (LHC). Today, Superconducting RF has become a vital technology not only for LHC but also for high intensity and energy upgrade of isotope separator on line device (HIE-ISOLDE) and the high luminosity (HL)-LHC project. More superconducting cavities will be needed for a potential high energy (HE)-LHC or for any of the future circular collider options, which are currently under study. To meet these demands, CERN has improved its SRF infrastructure over the recent years and has started several R&D lines including improved thin film coating techniques, high-power couplers, cold-test diagnostics, etc. This paper will give an overview of CERN's SRF activities today, and the challenges of future projects.