HL-LHC project

HL-LHC project
Name	HL-LHC project
Location	CERN
Type	Particle accelerator upgrade

HL-LHC project The High Luminosity Large Hadron Collider upgrade is an extensive program to enhance the performance of the Large Hadron Collider at CERN by increasing instantaneous luminosity, enabling more precise measurements and new searches in particle physics. The project builds on achievements from the original Large Hadron Collider campaigns that produced the discovery of the Higgs boson and precision tests of the Standard Model. It brings together technologies and institutions from across Europe, North America, and Asia to deliver complex accelerator, magnet, and detector upgrades.

Background and Motivation

The initiative follows the physics priorities established by the European Strategy for Particle Physics and recommendations from panels such as the Particle Physics Project Prioritization Panel and advisory input from the European Committee for Future Accelerators. Drivers include the need to extend sensitivity to rare processes tested by collaborations like ATLAS, CMS, LHCb, and ALICE, and to provide datasets comparable to proposed facilities such as the International Linear Collider and the Future Circular Collider. Historical precedents include upgrades implemented during the Long Shutdown 1 and Long Shutdown 2 at the Large Hadron Collider. The program aims to address outstanding questions related to electroweak symmetry breaking, supersymmetry, dark matter, and flavor physics, complementing experiments at facilities like Fermilab, DESY, and KEK.

Technical Design and Upgrades

Core accelerator upgrades center on novel superconducting magnet technologies developed in collaboration with laboratories such as CERN, ITER, Brookhaven National Laboratory, and Fermi National Accelerator Laboratory. Key components include new quadrupole magnet systems based on niobium-tin superconductors, upgraded radio-frequency cavities including crab cavity systems, and enhanced beam collimation and cryogenics derived from technology transfer between projects like LHC Upgrade (Phase II) and prior accelerator R&D programs. The design integrates advanced superconducting magnet manufacturing, precision beam instrumentation from institutions like SLAC National Accelerator Laboratory, and high-power radio-frequency sources. Systems for handling increased radiation dose involve materials and monitoring techniques developed alongside CERN radiation groups and partners in European Organization for Nuclear Research collaborations.

Construction and Installation

Installation phases are sequenced around planned Long Shutdown 3 windows to integrate components such as inner triplet magnets, crab cavities, and upgraded beam dump systems into the existing tunnel infrastructure originally built for the Large Hadron Collider. Civil engineering interfaces involve coordination with the Meyrin and Prévessin sites, and logistics draw on supply chains connecting firms in Switzerland, France, Germany, Italy, and Spain. Commissioning of cryogenic strings and magnet test benches uses facilities modeled on the SM18 test facility and leverages technical expertise from University of Oxford, École Polytechnique Fédérale de Lausanne, University of Manchester, and national laboratories including CERN collaborating centers.

Physics Goals and Scientific Impact

The upgrade targets an integrated luminosity increase enabling high-precision measurements of the Higgs boson couplings, rare processes such as Higgs boson pair production, and searches for phenomena predicted by theories like supersymmetry, extra dimensions, and various dark matter models. Results will impact global programs at institutions including Imperial College London, Princeton University, Massachusetts Institute of Technology, and observatories that test fundamental symmetries such as those at Gran Sasso National Laboratory. The dataset will strengthen flavor physics analyses by experiments from collaborations at CERN and elsewhere, informing theories developed by groups associated with the Perimeter Institute for Theoretical Physics, Institute for Advanced Study, and university departments worldwide. Outcomes will influence strategic planning for future accelerators such as the Future Circular Collider and proposals reviewed by bodies like the European Strategy Group.

Collaboration, Management, and Funding

The project is administered through governance mechanisms coordinated by CERN and involves national funding agencies including European Commission frameworks, the United States Department of Energy, the National Science Foundation, and agencies in member states such as CNRS, INFN, DESY, and STFC. Management structures draw on experience from large collaborations like ATLAS and CMS with project offices interfacing with technical boards, procurement offices, and safety committees in institutions such as European Organization for Nuclear Research member laboratories. Industry partnerships and consortia spanning corporations in Germany, France, Italy, United Kingdom, and United States supply superconducting strands, cryogenic equipment, and precision machinery.

Schedule, Testing, and Commissioning

Work is organized around phased schedules linked to the Long Shutdown windows for installation, followed by staged commissioning campaigns in which magnet strings, cryogenics, and radio-frequency cavities undergo integrated tests in facilities modeled on the SM18 test facility and accelerator test lines. Beam commissioning involves stepwise ramp-up protocols coordinated with experiments like ATLAS and CMS, while system acceptance tests employ standards developed with partners such as European Committee for Future Accelerators and national labs including Fermilab and SLAC National Accelerator Laboratory. The timeline aligns with European Strategy updates and peer reviews conducted by international advisory bodies to ensure readiness for physics runs.

Category:Particle accelerators Category:CERN projects