Speaker
Description
During the Long Shutdown 3 (LS3, from July 2026 to 2030), CERN surveyors will measure and re-align a large fraction of the 60 km accelerator beamline, requiring optimized survey procedures to ensure efficiency while maintaining accuracy and quality levels.
In preparation, CERN ‘s Geodetic Metrology group surveyed a 2.8 km Large Hadron Collider (LHC) arc during the 2024–2025 Year-End Technical Stop using standard measurement techniques, including 3D laser tracking, precision direct levelling, and ecartometry, together with wire measurements using the CERN photogrammetric train under final development.
This paper presents the measurement campaign and data acquisition for the survey of the LHC arc. The precision of each technique is evaluated and compared, and the datasets are combined using a global least-square adjustment to assess the compatibility of the different measurements. The study identifies opportunities to improve workflows and update future survey strategies particularly through increased automation and emerging measurement technologies.
