The High Luminosity Large Hadron Collider (HL-LHC) is an ambitious upgrade project to increase the LHC collision rate, significantly enhancing the physics discovery potential of the present LHC beyond 2030. As part of this effort, new components must be aligned within an elliptical 1σ tolerance zone, with radii of 0.17 mm vertically and 0.33 mm radially over 420 m around the two high luminosity experiments ATLAS and CMS. To meet these stringent requirements, all components will be equipped with micrometric alignment sensors, including 276 Wire Positioning Sensors and 148 Hydrostatic Levelling Sensors. These sensors must be rigidly attached to the component structures to enable precise position determination and they must be accurately pre-adjusted relative to external reference networks. These requirements led CERN’s geodetic metrology group to develop a modular support system. This system ensures an ergonomic sensor adjustment, a long-term positional stability, and a robustness against mechanical constraints. This paper presents the design approach and the results of the final testing and validation of the modular sensor support solution.
Sosin et al. (Thu,) studied this question.