The new equipment for the High-Luminosity LHC requires new large civil engineering structures on the sites of the ATLAS experiment in Meyrin, Switzerland (LHC Point 1) and the CMS experiment in Cessy, France (LHC Point 5).
On each site, the underground constructions consist of:
- A vertical shaft around 80 m deep and 10 m in diameter
- An underground service cavern (16 m in diameter and 46 m long) that will notably house cryogenics, cooling and ventilation equipment
- A 300-metre-long gallery for accelerator equipment and infrastructures, including power converters, protection systems, electrical distribution boxes, beam instrumentation and accelerator controls
- Four galleries measuring around 50 metres in length, connecting the new structures to the accelerator tunnel. These will house specific hardware, such as radiofrequency equipment for the crab cavities, superconducting links, and cryogenic distribution lines.
The connection to the LHC tunnel will be made via 12 vertical cores (1 m in diameter and 7 m deep), 6 on either side of the Interaction Point (IP), which will be drilled later and completed during Long-Shutdown 3 (2026-2028).
On each site, the surface structure consists of five new buildings, representing a total surface area of 2800 m2. These will house the cooling and ventilation equipment, cryogenic equipment, as well as electrical equipment.