High Luminosity Large Hadron Collider

The High Luminosity Large Hadron Collider (HL-LHC; formerly SLHC, Super Large Hadron Collider) is an upgrade to the Large Hadron Collider started in June 2018 that will boost the accelerator's potential for new discoveries in physics, starting in 2027. The upgrade aims at increasing the luminosity five-fold to 1035 cm−2s−1 for ATLAS and CMS and increase the integrated luminosity of the four main experiments (includes ALICE and LHCb) by a factor of 10, providing a better chance to see rare processes and improving statistically marginal measurements.
History.
Many different paths exist for upgrading the collider. A collection of different designs of the high luminosity interaction regions is being maintained by the European Organization for Nuclear Research (CERN).
A workshop was held in 2006 to establish which are the most promising options.
Increasing LHC luminosity involves reduction of beam size at the collision point and either reduction of bunch length and spacing, or significant increase in bunch length and population. The maximum integrated luminosity increase of the existing options is about a factor of 4 higher than the LHC ultimate performance, unfortunately far below the LHC upgrade project's initial ambition of a factor of 10. However, at the latest LUMI'06 workshop, several suggestions were proposed that would boost the LHC peak luminosity by a factor of 10 beyond nominal towards 1035 cm−2s−1.
The resultant higher event rate poses important challenges for the particle detectors located in the collision areas.
From 2011 to 2020, the project was led by Lucio Rossi. In 2020 the lead role was taken up by Oliver Brüning.
Project timeline.
The HL-LHC project was initiated in 2010, and the following has been the timeline till 2020, followed by the tentative future stages.
2010: HL-LHC was established at CERN as Design Study.
2011: The FP7 HL-LHC Design study was approved and started.
2014: The first preliminary report on the Design study was published.
2015: Budget and Schedule along with Technical Design report was made available.
2016: Hardware parts consisting of components and models was were validated.
Between 2018 and 2020: The prototypes were tested and final Technical Design report was published. The underground excavation work was also carried out.
Between 2019 and 2024: The construction and testing of hardware parts is planned.
2021-2023: All surface bindings would be delivered.
2022-2024: The of inner triplet string will be installed followed by its operation test.
2025-2027: New magnets, crab-cavities, cryo-plants, collimators, superconducting links, ancillary equipment, and absorbers are planned to be installed.
Injector upgrade.
As part of the Phase 2 Super LHC, significant changes will be made to the proton injector.
Superconducting Proton Linac (SPL): Accelerating protons with superconducting radio frequency cavities to an energy of 5 GeV.
Proton Synchrotron 2 (PS2): Accelerating the beam from 5 GeV at injection to 50 GeV at extraction.
Super Proton Synchrotron (SPS) Upgraded: The present SPS will be substantially upgraded to handle an increased beam intensity from PS2.