Speakers
Description
CERN is investigating two major linear collider concepts as successors to the LHC: the Compact Linear Collider (CLIC) and the Linear Collider Facility (LCF), the latter being based on the International Linear Collider (ILC) design. Both proposals involve twin laser-straight 5.6m internal diameter tunnels, extending to lengths of 29.6km for CLIC and 33.5km for LCF, forming symmetric layouts around central interaction regions (IR) located on CERN owned land adjacent to the CERN Prévessin site.
Both colliders are being developed in tandem, sharing both geographical and geological alignments, sited within well-characterized molasse rock ideal for Tunnel Boring Machine (TBM) excavation, with the interaction region at a depth of approximately 125m. CLIC also includes an injection complex comprised of cut and cover tunnels before transitioning into the main tunnel, adding surface and connection complexities.
Most recently designed for a single detector, the IR has since been reconfigured to support two detectors, prompting critical civil engineering decisions. One approach involves widening the beam delivery system (BDS) tunnel over a 2km span to 16m either side of the IR, housing both detectors within a single cavern. Alternatively, the BDS splits into two tunnels: each branch feeding a separate, smaller cavern for increased stability, minimizing excavation footprint but introducing additional tunnelling.
This paper provides a comparative overview of these linear collider studies, focusing on civil engineering aspects, geographical and geological environments, sustainability, and the shared and unique technical challenges of each study.
