Long Shutdown 1
Generated by GPT-5-miniExpansion Funnel Raw 65 → Dedup 0 → NER 0 → Enqueued 0
| Long Shutdown 1 | |
|---|---|
| Name | Long Shutdown 1 |
| Country | Switzerland |
| Location | CERN |
| Period | 2013–2015 |
| Facility | Large Hadron Collider |
| Predecessor | Run 1 |
| Successor | Run 2 |
Long Shutdown 1 was a scheduled multi-year maintenance and upgrade period at CERN for the Large Hadron Collider and its injector chain between 2013 and 2015. The shutdown aimed to repair, consolidate, and upgrade superconducting circuits, cryogenics, and injector components to enable higher energy proton collisions for the following operational period, coordinating work across collaborations such as ATLAS, CMS, ALICE, and LHCb. The program required global cooperation among institutions including European Organization for Nuclear Research, national laboratories such as Fermilab and DESY, and university groups from Oxford University, MIT, and École Polytechnique.
Background and Objectives
The planning for the shutdown followed discoveries and operational experience from Run 1 at the Large Hadron Collider, notably the observation of a Higgs-like boson reported by ATLAS and CMS after analyses influenced by teams at Imperial College London and University of California, Berkeley. Key objectives included replacing magnets and consolidating the superconducting interconnects that had caused quenches during initial commissioning, improving the cryogenic system reliability developed with contractors and partners such as Air Liquide and Siemens, and upgrading injector performance at facilities like the Proton Synchrotron and Super Proton Synchrotron to meet luminosity projections set with input from CERN Council and the European Strategy for Particle Physics.
Timeline and Major Activities
The shutdown started after the 2012–2013 winter technical stop and extended through 2014 into 2015, with scheduling overseen by the LHC Machine Committee and project offices linked to the Director-General of CERN. Early phases focused on consolidation of interconnects and repair of splices following the 2008 incident that had involved the Sector 3-4 region and led to upgrades informed by investigations by panels including experts from STFC and IN2P3. Mid-term activities encompassed installation of new cryogenic distribution lines and powering tests coordinated with experiments LHCb and ALICE to minimize disruption to detector maintenance windows planned by the Technical Coordination teams. The final months included integrated commissioning exercises and beam tests with injectors coordinated with CERN Accelerator School training sessions.
Technical Upgrades and Maintenance Works
Major technical works replaced and requalified superconducting busbar splices and strengthened cold mass supports originally designed with input from INFN and CEA. Additional cryogenic capacity was added via new helium refrigeration modules and upgrades to the cryostat interfaces, planned with suppliers and specialists from Danfoss and Air Liquide. Collimation systems received hardware and control upgrades coordinated by CERN Accelerator Beam Physics groups and teams from University of Manchester and TU Darmstadt to improve machine protection. The injectors—Linac2 and Proton Synchrotron Booster—underwent RF and power-supply overhauls influenced by designs from Brookhaven National Laboratory and GSI Helmholtz Centre, while control-room systems saw software and timing upgrades leveraging work by EPFL and Uppsala University teams. Detector collaborations used the shutdown to install improved tracking systems in ATLAS and CMS and to service calorimeters in ALICE, guided by engineering groups from CERN Detector Technologies and partner institutions like Lawrence Berkeley National Laboratory.
Impact on LHC Operations and Experiments
The upgrades enabled the Large Hadron Collider to resume operations at higher center-of-mass energies and with increased integrated luminosity during Run 2, affecting physics programs pursued by collaborations such as ATLAS, CMS, ALICE, and LHCb. Increased reliability reduced the frequency of quenches and unscheduled stops, improving data-taking efficiency reported by experiment spokespersons including leaders from CERN and participating universities. The injector improvements supported more intense bunch patterns, which influenced analyses using datasets from experiments associated with institutions such as Johns Hopkins University, University of Tokyo, and University of Melbourne. The improved machine protection and collimation permitted more aggressive operational parameters that aided searches for phenomena proposed in theories from groups at Princeton University and Stanford University.
Safety, Personnel, and Organizational Management
Safety oversight during the shutdown engaged CERN’s safety groups and national regulators, with occupational health and radiation protection protocols coordinated with specialists from World Health Organization guidance and national agencies like ASN (France). Large-scale teams of engineers and technicians from institutions including CERN, Fermilab, DESY, and multiple universities required detailed scheduling and training overseen by the Human Resources and Project Management Office at CERN; logistics involved coordination with local authorities in Meyrin and partner labs such as STFC Rutherford Appleton Laboratory. Major safety milestones included lock-out/tag-out procedures, radiological surveys, and cryogen handling certifications informed by standards from ISO committees and industrial partners.
Legacy and Lessons Learned
The shutdown yielded lasting technical improvements that underpinned the successful higher-energy Run 2 program and informed planning for subsequent upgrades such as the High-Luminosity Large Hadron Collider project developed by consortia including CERN and ITER-adjacent suppliers. Lessons emphasized the importance of robust interconnect quality assurance, cross-institutional coordination between projects led by groups at University of Chicago and Caltech, and sustained investment in injector modernization advocated by advisory panels including the European Strategy Group. Organizationally, the experience shaped risk-management practices and informed future shutdown planning used by accelerator centers like KEK and SLAC National Accelerator Laboratory.