Chapter 15: Integration, (de-)installation and alignment

Abstract

The HL-LHC will require modifying the machine and infrastructure installations of the LHC in several points along the Accelerator Ring, in particular: P1, P2, P4, P5, P6, P7 and P8.

Part of the modifications and improvement in P2, P4, P7 and P8 shall be completed during Long Shutdown 2 (LS2) and be operational for LHC Run 3, while the largest part of the interventions will take place in Long Shutdown 3 (LS3) and they will affect primarily P1, P4, P5, P6 and P7. The activities required point by point will be therefore listed and analysed here below.

The Project evolution has allowed and obliged to revise and refine the previous integration plan. Here below the main changes are singled out

- Point 1 and Point 5

o The LHC Machine layout has been made compliant with the optics version 1.4 that integrates the deployment of the Full Remote Alignment and the results of the matching section optimization. The present layout is based on updated and refined equipment designs considering the progress of the engineering design of each system. This includes in particular: magnet cryostats, DFX, Crab Cavity cryo-modules, collimators that have all seen important evolution in their design.

o The system optimization implied a revision of the localization of some of the equipment, i.e. the power converters feeding the circuits of the Higher Order correctors magnets that are in the Corrector Package have been moved from the new HL-LHC underground infrastructures to the service alcoves of the LHC tunnel.

o Following the refinement of the services design and the machine equipment requirements, the full integration in the new HL-LHC underground infrastructures has been reviewed. The integration activity in this area is strictly linked to the finalization of the construction design of the caverns that are being built during LS2.

o In a similar way, and for the same reasons, the integration of the new surface buildings and the connecting technical galleries has been revisited in detail, leading to an optimization in the gallery topology and refinement in the building design.

Point 4:

o The cryogenic system upgrade at Point 4 has been reviewed. In order to support the operation in Sector 3-4 (that is fed by a refrigerator unit inherited from the LEP machine) the refrigerator will be upgraded, but without impacting the cryogenic distribution network. The previously foreseen mobile refrigerator that was foreseen to cool the LHC RF accelerating cavities for testing and conditioning purposes has been abandoned.

o The conceptual design of the Hollow-Electron Lenses has been integrated in the tunnel together with their services validating the design choices.

Point 6

o The previous foreseen upgrade of the Q5 units has been abandoned.The presently installed units will be operated in the HL-LHC configuration as they currently are in the existing LHC configuration.

o The horizontal beam dump dilution kicker system is planned to be upgraded with the installation of one additional kicker module for each beam.

o The Beam Dump block will be upgraded already in LS2 with new upstream windows. Additionally, the dump block will be mechanically separated from the beam dump line and its support system modified to allow for an improved absorption of the shock waves during beam impact.

o The entire Beam Dump block is planned to be replaced during LS3 in preparation for the HL-LHC exploitation.