High-Luminosity Large Hadron Collider
General Info


Geneva, Switzerland

legal status



remote, physical

The Large Hadron Collider (LHC) is one of the most powerful scientific instruments ever built. It has been exploring the energy frontier since 2010, brought together a global user community of more than10’000 scientists and led to the experimental discovery of the Higgs boson in 2012. The LHC will reach its lifetime end in 2025 when it will have accumulated an integrated luminosity of approximately 450fb-1 (total data set delivered to the experiments). To extend its physics reach, in particular with regard to the Higgs boson and the structure and evolution of the universe, the LHC requires a major upgrade to increase its instantaneous luminosity (rate of proton-proton collisions) by a factor of 5 beyond its nominal design value, and the integrated luminosity by a factor of 10. This is the goal of the High-Luminosity LHC (HL-LHC), which will extend the LHC operation until 2041. Being a highly complex and technologically challenging machine, such an upgrade required about 10 years of R&D before it could be implemented. HL-LHC relies on a number of key innovative technologies, each representing exceptional technological challenges, such as: cutting edge 11-12 Tesla superconducting Nb3Sn quadruple magnets, very compact superconducting RF (radio-frequency) cavities for beam rotation at the interaction points with ultra-precise phase control, new technology for beam collimation, high current superconducting links with negligible energy dissipation, very precise high-current power converters with energy recovery, new surface treatment of the beam screen for electron-cloud suppression, remote controlled robotics and intervention tools. The HL-LHC project started in 2011 as an EU funded Design Study that identified the key upgrade strategies, and was formally approved by the CERN Council in 2016. It required the construction of new access shafts and underground galleries (for a total of 1.5 km) and caverns to house the new equipment and to facilitate access and maintenance activities during machine operation, and new surface buildings to house new equipment like cryogenic refrigeration and industrial cooling and ventilation units. The civil engineering work started in 2018 and it was completed in 2022 on time and budget. The HL-LHC components are scheduled to be installed during the third Long Shutdown period of the LHC, starting in 2026. The start of the HL-LHC operation period is planned for 2029. The project has an overall material cost of about 1,600 MCHF and requires about 2,200 FTEs over a period of ca. 12 years. From the beginning, the HL-LHC has been devised as an international project, with about 10% of its budget coming from external institutes and international collaborations via in-kind contributions. The HL-LHC project is complemented by an upgrade of the LHC injector complex, which was successfully implemented during the second LHC Long Shutdown from 2018 to 2021, and by upgrade projects of the LHC detectors, carried out in phases.
Total Investment 1700 M€ Design 248 M€ Preparation 41 M€ Implementation 1415 M€ Operation 164 M€/year Project Landmark 2006 2008 2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038 RM06 RM08 RM10 RM16 RM18 RM21 LA24
Roadmap Entry
as project: 2006
as landmark: 2016
Total investment
1700 M€
Design Phase
248 M€
Preparation Phase
41 M€
Implementation Phase
1415 M€
Operation start
164 M€/year
The HL-LHC project is set to maintain the European leadership position in High Energy Physics until 2041. It will provide both scientific and societal impact in various ways: by widely disseminating its results through Open Science publications and scientific outreach activities; by developing and operating many new technologies on an industrial scale, thereby contributing also to the development of future accelerators, like Future Circular Collider (FCC) at CERN, and to society more broadly by training thousands of young physicists, engineers and technicians, hence providing highly-qualified STEM workforce to industry and other fields of science. Collaboratively developed with global industry partners, the HL-LHC pioneering technologies also yield significant socio-economic impacts. Examples of high impact applications are: high-efficiency superconducting electricity transportation lines, compact magnets for more affordable cancer radiotherapy and for high-field magnetic resonance imaging, superconducting power distribution for electric propulsion in future low-emission aircraft, efficient power distribution in data centers, advanced materials for thermal management in electronics and space applications. HL-LHC allowed the development and industrialization of these technologies, facilitating their transfer to other applications, as demonstrated for example by recently started collaborations with Airbus and META for the use of superconducting cables in aircraft and data centers.
The HL-LHC will provide hadron (proton-proton and heavy-ion) collisions at unprecedented energies and luminosities for several large international particle physics experiments, bringing together in total more than 10’000 scientists from all over the world. CERN, as the host laboratory, provides physical access to experimental areas and control rooms, as well all the facilities and services needed by the LHC user community, including: technical infrastructure and support, safety training and support, office space, modern library, computing facilities, conference and meeting rooms with video equipment, several hostels and restaurants, bank office, and medical service. The mission of the Worldwide LHC Computing Grid (WLCG) is to provide global computing resources for the storage, distribution and analysis of the data generated by the LHC. WLCG currently combines about 1.4 million computer cores and 3 exabytes of storage from over 160 sites in more than 40 countries. This massive distributed computing infrastructure provides more than 10’000 physicists around the world with near real-time access to LHC data, and the power to process it. It runs over 2 million tasks per day with global transfer rates exceeded 300 GB/s. These numbers will increase for the time of the HL-LHC operation as the data production rates and the corresponding computing resources will be significantly higher.
S S H D I G I T E N E E N V H & F
AUP (USA): The Nb3Sn focusing quadrupole magnets that will be installed around ATLAS and CMS are designed and constructed in collaboration with the HL-LHC Accelerator Upgrade Project (AUP) in the USA. AUP is also responsible for the production of 10 Radio Frequency Dipole (RFD) crab-cavities. TRIUMF (Canada) will be responsible for integrating the RFD cavities into their final cryostats. KEK (Japan) will lead the production of 6 Nb-Ti based magnets for the separation and recombination of the beams around the ATLAS and CMS experiments. INFN (Italy) is responsible for the production of 6 Nb-Ti based magnets for the separation and recombination of the beams around the ATLAS and CMS experiments, as well as the design and construction of the nine different families of higher order mode correctors. IHEP (China) leads the production of a novel corrector magnet design. United Kingdom: STFC, Cockcroft Institute, Royal Holloway, John Adams Institute and several universities will ensure the integration of the second type of crab-cavities into their cryostats, as well as contribute to the development of several beam diagnostic instruments. CIEMAT (Spain): will be in charge of the development and production of Nb-Ti based orbit corrector magnets.