Validation of the Crab-Cavities Internal Monitoring Strategy

The high luminosity upgrade for the LHC at CERN (HL-LHC project[1], [2]) will extend the discovery potential of the LHC by a factor 10 [3]. It relies on key innovative technologies among which superconducting cavities for beam rotation, named “crab-cavities”. Alignment purposes of such RF cavities will involve apositioning to 0.5mm at 3σunder harsh conditions. Twoalignment monitoring systems have been compared and referenced to a laser tracker measurement in order to validatetheir accuracy under standard conditions (room temperature, atmospheric pressure, no radiation). In parallel, both systems are being validated regarding cryogenic and/or radiation aspect. This document presents the main results of thetestcampaign conductedin laboratory in order to validate the alignment strategy.