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| long shutdown (LHC) | |
|---|---|
| Name | Long shutdown (LHC) |
| Location | CERN |
| Status | Ongoing |
| Period | Large Hadron Collider |
| Purpose | Upgrade and maintenance |
long shutdown (LHC) The long shutdown at the Large Hadron Collider is a planned multi-year cessation of high-energy operations at CERN to perform major maintenance, upgrades, and consolidation work on the accelerator complex. It enables coordinated interventions involving international collaborations such as ATLAS, CMS, LHCb, and ALICE and intersects with broader projects tied to High-Luminosity LHC and European infrastructure programs. The process engages national laboratories like Fermilab, DESY, KEK, and institutions including European Organization for Nuclear Research partners and funding bodies such as the European Commission.
The shutdown regime grew from experiences during the original construction and operations phases that involved entities like Stanford Linear Accelerator Center, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory, SLAC National Accelerator Laboratory, and projects such as LEP and Tevatron. Early LHC maintenance and consolidation drew on expertise from collaborations including ATLAS, CMS, LHCb, ALICE, and detector groups linked with IHEP (Beijing), INFN, CNRS. Purpose-driven objectives included reliability improvements influenced by incidents like the 2008 magnet quench that required responses from teams associated with Max Planck Society, Royal Society, and technical standards used by IEC and IEEE. Long shutdowns serve to implement upgrades referenced in roadmaps by European Strategy for Particle Physics and coordination with programs such as ESS and ITER.
LS1 followed commissioning runs and incorporated international contributions from CERN member states and partners such as United States Department of Energy, Japan Ministry of Education, Culture, Sports, Science and Technology, Russian Academy of Sciences, and provider firms like Siemens and Thales Group. LS2 focused on consolidation aligning with proposals by the High-Luminosity LHC task force and involved collaborations with GSI Helmholtz Centre for Heavy Ion Research, CEA Saclay, University of Oxford, Massachusetts Institute of Technology, and Caltech. LS3 is planned as the major upgrade phase coordinating efforts from the European Strategy Group, Science and Technology Facilities Council, National Science Foundation, Swiss Federal Institute of Technology in Lausanne, and vendor partnerships with ABB and Andritz. Each shutdown corresponds to milestone documents endorsed by committees like CERN Council, Research Councils UK, Horizon 2020, and advisory panels including SPSC (CERN), APPEC, and ESFRI.
Works include replacement and reinforcement of superconducting niobium-titanium magnets and cryogenic systems developed with partners such as Oxford Instruments, Bruker, and research groups at ETH Zurich and École Polytechnique. Upgrades to radio-frequency systems and beam instrumentation involved collaborations with DESY, CERN Accelerator School, Brookhaven National Laboratory, Lawrence Livermore National Laboratory, and firms like Thales Alenia Space. Injector chain refurbishments affected complexes such as PS Booster, Proton Synchrotron, and Super Proton Synchrotron, requiring coordination with teams from Istituto Nazionale di Fisica Nucleare, Politecnico di Milano, TU Darmstadt, Université Paris-Saclay, and Universidad de Valencia. Detector upgrades encompassed silicon tracker replacements with technology from HPK, STMicroelectronics, and institutes like University of Manchester, CERN PH, Vrije Universiteit Amsterdam, and Institute of High Energy Physics (IHEP) Beijing. Power converters, vacuum systems, collimation, and machine protection were enhanced drawing on expertise from Siemens, Schneider Electric, Hitachi, and laboratories including CEA and CNRS/IN2P3.
Experimental collaborations such as ATLAS, CMS, LHCb, and ALICE schedule detector interventions including tracker replacements, calorimeter refurbishments, and trigger system overhauls with input from institutions like Imperial College London, Harvard University, Princeton University, University of Tokyo, and University of Geneva. Upgrades enable higher luminosity targets championed by the High-Luminosity LHC project and analysis programs pursued at facilities including CERN Data Centre, GRIDPP, Open Science Grid, and research groups tied to IHEP, TRIUMF, McGill University, and University of Toronto. Detector downtime impacts data-taking cycles used by physics programs studying topics related to the Higgs boson, top quark, B mesons, and searches for supersymmetry and dark matter with analysis pipelines maintained by collaborations like ROOT, GEANT4, and software teams at CERN IT.
Safety protocols adhere to regulations and standards from organizations such as European Commission, World Health Organization, International Atomic Energy Agency, and industrial standards bodies like ISO, IEC, and IEEE. Commissioning phases involve beam tests, injector validation, and machine protection systems integrating expertise from CERN BE Department, CERN EN Department, CERN Safety Commission, and partner labs including FERMILAB, DESY, and KEK. Restart sequences coordinate operations with emergency services in Geneva, French Autorité de Sûreté Nucléaire, and technical oversight by CERN Council, Director-General of CERN, and local authorities including Swiss Federal Office of Public Health.
Planning is governed by strategic documents from CERN Council, funding agreements with European Commission, bilateral memoranda with national agencies like DOE, MEXT, INFN, and coordination platforms such as European Strategy Group, SPSC (CERN), LHCC, and review panels involving Fermilab, DESY, KEK, JINR, and university consortia. Project management uses timelines aligned with international roadmaps like ESFRI and funding instruments including Horizon Europe, Framework Programme, and national research grants administered by organizations such as UKRI, ANR, DFG, NSF, and JST. Scheduling balances accelerator operations, detector upgrades, resource allocations from labs including CERN, Brookhaven, GSI, and contractor delivery from firms like Siemens, ABB, Thales.