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Identification
Hosting Legal Entity
European Organization for Nuclear Research (CERN)
Location
385 Route de Meyrin, CERN, Merin, PO: 1217 (Switzerland)
Structure
Type Of RI
Single-sited
Coordinating Country
Switzerland
Status
Status
Current Status:
Operational since 2025
Timeline
Being upgraded since 2018 to 2020
Operational since 2008 to 2018
Design/planning since 1984
Scientific Description
The Standard Model of particle physics – atheory developed in the early 1970s that describes the fundamental particles and theirinteractions – has precisely predicted a widevariety of phenomena and so far successfullyexplained almost all experimental results inparticle physics. But the Standard Model isincomplete. It leaves many questions open,which the LHC will help to answer. Our mission is to:• provide a unique range of particle accelerator facilities that enable research at the forefront of human knowledge.• perform world-class research in fundamental physics.• unite people from all over the world to push the frontiers of science and technology, for the benefit of all. We want to:• use our world-class accelerator, the LHC, to its maximum potential during its high-luminosity phase;• provide maintain and continually update a diverse, complementary scientific programme serving a broad community, including contributing to long-baseline neutrino projects outside Europe;• prepare for a post-LHC high-energy accelerator project through design studies (CLIC and FCC) and a vigorous accelerator R&D programme (AWAKE and others).

RI Keywords
Heavy-ion detector, Large Hadron Collider, High energy physics, proton collisions, LHC, Hadron physics, Large Ion Collider, Particle physics, Particle detectors, High-energy collisions, Muons, CERN, Particle accelerators
Classifications
RI Category
High Energy Physics Facilities
Scientific Domain
Physics, Astronomy, Astrophysics and Mathematics
ESFRI Domain
Physical Sciences and Engineering
Equipment
ATLAS particle detector / ATLAS experiment

ATLAS is one of two general-purpose detectors at the Large Hadron Collider (LHC). It investigates a wide range of physics, from the search for the Higgs boson to extra dimensions and particles that could make up dark matter. Although it has the same scientific goals as the CMS experiment, it uses different technical solutions and a different magnet-system design. Beams of particles from the LHC collide at the centre of the ATLAS detector making collision debris in the form of new particles, which fly out from the collision point in all directions. Six different detecting subsystems arranged in layers around the collision point record the paths, momentum, and energy of the particles, allowing them to be individually identified. A huge magnet system bends the paths of charged particles so that their momenta can be measured. The interactions in the ATLAS detectors create an enormous flow of data. To digest the data, ATLAS uses an advanced “trigger” system to tell the detector which events to record and which to ignore. Complex data-acquisition and computing systems are then used to analyse the collision events recorded. At 46 m long, 25 m high and 25 m wide, the 7000-tonne ATLAS detector is the largest volume particle detector ever constructed. It sits in a cavern 100 m below ground near the main CERN site, close to the village of Meyrin in Switzerland. More than 3000 scientists from 174 institutes in 38 countries work on the ATLAS experiment (February 2012). https://atlas.cern/

LHC particle accelerator

The Large Hadron Collider (LHC) is the world’s largest and most powerful particle accelerator. It first started up on 10 September 2008, and remains the latest addition to CERN’s accelerator complex. The LHC consists of a 27-kilometre ring of superconducting magnets with a number of accelerating structures to boost the energy of the particles along the way. LS1,LHC (Image: Anna Pantelia/CERN) Inside the accelerator, two high-energy particle beams travel at close to the speed of light before they are made to collide. The beams travel in opposite directions in separate beam pipes – two tubes kept at ultrahigh vacuum. They are guided around the accelerator ring by a strong magnetic field maintained by superconducting electromagnets. The electromagnets are built from coils of special electric cable that operates in a superconducting state, efficiently conducting electricity without resistance or loss of energy. This requires chilling the magnets to ‑271.3°C – a temperature colder than outer space. For this reason, much of the accelerator is connected to a distribution system of liquid helium, which cools the magnets, as well as to other supply services. LS1,Magnets,TI2,PMI2,LHC,dipole,descent,replacement Replacing one of the LHC's dipole magnets (Image: Maximilien Brice/CERN) Thousands of magnets of different varieties and sizes are used to direct the beams around the accelerator. These include 1232 dipole magnets 15 metres in length which bend the beams, and 392 quadrupole magnets, each 5–7 metres long, which focus the beams. Just prior to collision, another type of magnet is used to "squeeze" the particles closer together to increase the chances of collisions. The particles are so tiny that the task of making them collide is akin to firing two needles 10 kilometres apart with such precision that they meet halfway. All the controls for the accelerator, its services and technical infrastructure are housed under one roof at the CERN Control Centre. From here, the beams inside the LHC are made to collide at four locations around the accelerator ring, corresponding to the positions of four particle detectors – ATLAS, CMS, ALICE and LHCb.

CMS detector / CMS experiment

The Compact Muon Solenoid (CMS) is a general-purpose detector at the Large Hadron Collider (LHC). It has a broad physics programme ranging from studying the Standard Model (including the Higgs boson) to searching for extra dimensions and particles that could make up dark matter. Although it has the same scientific goals as the ATLAS experiment, it uses different technical solutions and a different magnet-system design. The CMS detector is built around a huge solenoid magnet. This takes the form of a cylindrical coil of superconducting cable that generates a field of 4 tesla, about 100,000 times the magnetic field of the Earth. The field is confined by a steel “yoke” that forms the bulk of the detector’s 14,000-tonne weight. An unusual feature of the CMS detector is that instead of being built in-situ like the other giant detectors of the LHC experiments, it was constructed in 15 sections at ground level before being lowered into an underground cavern near Cessy in France and reassembled. The complete detector is 21 metres long, 15 metres wide and 15 metres high. The CMS experiment is one of the largest international scientific collaborations in history, involving 4300 particle physicists, engineers, technicians, students and support staff from 182 institutes in 42 countries (February 2014). https://cms.cern/detector

ALICE heavy-ion detector / ALICE experiment

ALICE (A Large Ion Collider Experiment) is a heavy-ion detector on the Large Hadron Collider (LHC) ring. It is designed to study the physics of strongly interacting matter at extreme energy densities, where a phase of matter called quark-gluon plasma forms. All ordinary matter in today’s universe is made up of atoms. Each atom contains a nucleus composed of protons and neutrons (except hydrogen, which has no neutrons), surrounded by a cloud of electrons. Protons and neutrons are in turn made of quarks bound together by other particles called gluons. No quark has ever been observed in isolation: the quarks, as well as the gluons, seem to be bound permanently together and confined inside composite particles, such as protons and neutrons. This is known as confinement. Collisions in the LHC generate temperatures more than 100,000 times hotter than the centre of the Sun. For part of each year the LHC provides collisions between lead ions, recreating in the laboratory conditions similar to those just after the big bang. Under these extreme conditions, protons and neutrons "melt", freeing the quarks from their bonds with the gluons. This is quark-gluon plasma. The existence of such a phase and its properties are key issues in the theory of quantum chromodynamics (QCD), for understanding the phenomenon of confinement, and for a physics problem called chiral-symmetry restoration. The ALICE collaboration studies the quark-gluon plasma as it expands and cools, observing how it progressively gives rise to the particles that constitute the matter of our universe today. The ALICE collaboration uses the 10,000-tonne ALICE detector – 26 m long, 16 m high, and 16 m wide – to study quark-gluon plasma. The detector sits in a vast cavern 56 m below ground close to the village of St Genis-Pouilly in France, receiving beams from the LHC. The collaboration counts more than 1000 scientists from over 100 physics institutes in 30 countries. http://aliceinfo.cern.ch/Public/Welcome.html

UPGRADE: HL-LHC

The High Luminosity LHC (HL-LHC) is an upgrade of the LHC to achieve instantaneous luminosities a factor of five larger than the LHC nominal value, thereby enabling the experiments to enlarge their data sample by one order of magnitude compared with the LHC baseline programme. Following five years of design study and R&D, this challenging project requires now about ten years of developments, prototyping, testing and implementation; hence operation is expected to start in the middle of the next decade. The timeline of the project is dictated by the fact that, at the beginning of the next decade, many critical components of the accelerator will reach the end of their lifetime due to radiation damage and will thus need to be replaced. The upgrade phase is therefore crucial not only for the full exploitation of the LHC physics potential, but also to enable operation of the collider beyond 2025. http://hilumilhc.web.cern.ch/

LHCb detector / LHCb experiment

The Large Hadron Collider beauty (LHCb) experiment specializes in investigating the slight differences between matter and antimatter by studying a type of particle called the "beauty quark", or "b quark". Instead of surrounding the entire collision point with an enclosed detector as do ATLAS and CMS, the LHCb experiment uses a series of subdetectors to detect mainly forward particles - those thrown forwards by the collision in one direction. The first subdetector is mounted close to the collision point, with the others following one behind the other over a length of 20 metres. An abundance of different types of quark are created by the LHC before they decay quickly into other forms. To catch the b quarks, LHCb has developed sophisticated movable tracking detectors close to the path of the beams circling in the LHC. The 5600-tonne LHCb detector is made up of a forward spectrometer and planar detectors. It is 21 metres long, 10 metres high and 13 metres wide, and sits 100 metres below ground near the village of Ferney-Voltaire, France. About 700 scientists from 66 different institutes and universities make up the LHCb collaboration (October 2013). http://lhcb-public.web.cern.ch/lhcb-public/

Collaborations
ESFRI
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Date of last update: 21/06/2019
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