Six years after its discovery, the Higgs boson has at last been observed decaying to fundamental particles known as bottom quarks. The finding, presented by the ATLAS and CMS collaborations, is consistent with the hypothesis that the all-pervading quantum field behind the Higgs boson also gives mass to the bottom quark.
During the summer of 1962, the CERN Photo Club and Public Information Department organized a photographic competition on the theme, ‘How a visitor sees CERN’.
Fabiola Gianotti, CERN's Director General, places a time capsule at point 1 during a ground-breaking ceremony marking the launch of the civil engineering work for the High-Luminosity LHC (HL-LHC) project.
The “crab cavities” tests to rotate a beam of protons – a world first – is a success. The test uses a beam from CERN’s Super Proton Synchrotron accelerator and shows that bunches of protons can be tilted using superconducting transverse radiofrequency cavities. These cavities are a key component of the High-Luminosity Large Hadron Collider, the future upgrade of the LHC.
Linac 4, the newest accelerator acquired since the LHC, is inaugurated at a ceremony. The linear accelerator will feed the CERN accelerator complex with particle beams of higher energy, which will allow the LHC to reach higher luminosity by 2021. It will replace Linac 2 during the long technical shut down in 2019-20.
From CERN press release dated 17 July 2016:
On 17 July 2016, Romania became the twenty-second Member State of CERN.
Contacts between CERN and Romania began back in 1991, when a scientific and technical cooperation agreement was signed, establishing the legal framework for later developments.
CERN's nuclear physics facility, ISOLDE, began producing ion beams at higher energies. The first cryomodule of the new HIE-ISOLDE (High-Intensity and Energy ISOLDE) accelerator is up and running, increasing the beam energy from 3 to 4.3 MeV per nucleon.
Three years after the discovery of the Higgs boson, the ATLAS and CMS collaborations present combined measurements of the many of its properties at the Large Hadron Collider Physics Conference 2015. By combining their analyses of the data collected in 2011 and 2012, ATLAS and CMS draw the sharpest picture of the newly-discovered particle.
The ALICE experiment at the LHC publishes a result in Nature Physics confirming a fundamental symmetry of nature to an unprecedented precision for light nuclei. The precise measurement of the difference between ratios of the mass and electric charge of light nuclei and antinuclei are based on the ALICE experiment’s abilities to track and identify particles produced in high-energy heavy-ion collisions at the LHC.
The LHCb experiment at CERN’s Large Hadron Collider reports the discovery of a class of particles known as pentaquarks.
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Possible layout of the quarks in a pentaquark particle. The five quarks might be tightly bound (left). They might also be assembled into a meson (one quark and one antiquark) and a baryon (three quarks), weakly bound together (Image: Daniel Dominguez)
From the CERN website:
After an almost two-year shutdown and several months of re-commissioning, the LHC delivers collisions to all of its experiments at the unprecedented energy of 13 TeV, almost double the collision energy of its first run. This marks the start of run 2 at the LHC, opening the way to new discoveries. The LHC will run round the clock for the next three years.
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Radioactive ion beams from many chemical elements are produced at ISOLDE and more than 1000 Radioactive Ion Beams (RIBs) are available for the users. With a Carbon nanotube target the element boron could be produced as a RIB for the first time and the isotope 8B (T1/2=770 ms) could be observed. With this addition to the palette of ISOLDE beams the Facility can now provide beams from 74 chemical elements to the user community.
The first beams at the energy of 13 TeV circulated in the Large Hadron Collider at XXXX this morning
From the CERN website, posted 9 December 2014:
From the CERN website, posted 17 December 2014:
Last week the cryogenics team at CERN finished filling the arc sections of the Large Hadron Collider (LHC) with liquid helium. The helium, which is injected into magnetsthat steer particle beams around the 27-kilometre accelerator, cools the machine to below 4 degrees kelvin (-269.15°C).
The LHCb experiment announces the discovery of two new particles in the baryon family, which were predicted by the quark model but had never been seen before.
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On 29 September 1954, the CERN Convention entered into force, officially establishing the European Organization for Nuclear Research with 12 European member states. CERN celebrated “60 years of science for peace” with an official ceremony on 29 September and numerous public events taking place throughout the year.
Check out the website that contains a record of the activities that marked the Organization’s 60th Anniversary.
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Inspired by the 1PeV events, IceCube began a follow up search with combined two powerful techniques. The first was to distinguish neutrino interactions that originated inside the detector from events which originate outside it. The second technique capitalized on the fact that downgoing atmospheric neutrinos should be accompanied by a cosmic-ray air shower depositing one or more muons inside IceCube whereas cosmic neutrinos should be unaccompanied. Consequently, a very high energy isolated downgoing neutrino is likely to be cosmic.
From the CERN website, posted 5 May 2014:
From CERN press release dated 15 January 2014:
At a ceremony today at CERN, the Israeli flag was hoisted for the first time to join the other 20 flags of the organization’s Member States, after UNESCO officially recorded Israel's accession as a new CERN Member State on 6 January 2014.
The LHC will be upgraded to 14 TeV collision energy. The first major upgrade is Phase I, scheduled for 2018, and Phase 2 in 2022. The experiments will continue taking data until 2035. By then ATLAS expects to have collected 100 times more data than they had at the beginning of Long Shutdown 1.
François Englert (left) and Peter Higgs at CERN on 4 July 2012, on the occasion of the announcement of the discovery of a Higgs boson by the ATLAS and CMS experiments (Image: Maximilien Brice/CERN)
In the middle of 2013 the success of combined technical and physical efforts was demonstrated in three papers published in Nature within the space of one month.
At 8.25am the shift crew in the CERN Control Centre extract the beams from the Large Hadron Collider (LHC) for the last time before the machine's first Long Shutdown. The two-year shutdown will see a hive of maintenance activity on all of CERN's accelerators. Work on the LHC will include the consolidation of more than 10,000 interconnections between magnets.
The news on the CERN website posted 18 February 2013:
On Saturday at 8.25am the shift crew in the CERN Control Centre extracted the beams from the Large Hadron Collider (LHC) for the last time before the machine's first Long Shutdown. The following message marked the event on LHC Page 1: "No beam for a while. Access required: Time estimate ~2 years."
(Image: The ATLAS pixel detector is reinserted into the experiment after upgrade work)
In February 2013, the LHC and its experiments, including ATLAS, began its first Long Shutdown for maintenance and first upgrades to prepare for higher luminosity operations. By the end of 2013, ATLAS had produced almost 300 publications.
(Image: Groundbreaking for the CERN-MEDICIS building. From left - R. Meuli, Chef du Département de Radiologie Médicale, CHUV, D. Hanahan, Director, Swiss Institute for Experimental Cancer Research R. Heuer, Directeur général, CERN Y. Grandjean Secrétaire général, HUG P. Piet Van Duppen, Nuclear Spectroscopy Group, Katholieke Universiteit Leuven. Credit: Maximillien Brice/ CERN)
The ATLAS and CMS collaborations submitted papers to the journal Physics Letters B outlining the latest on their searches for the Higgs boson. The teams reported even stronger evidence for the presence of a new Higgs-like particle than they announced the month before.
On 4 July 2012, as a curtain raiser to the year’s major particle physics conference, ICHEP 2012 in Melbourne, the ATLAS and CMS experiments present their latest preliminary results in the search for the long-sought Higgs particle. Both experiments have observed a new particle in the mass region around 125-126 GeV. The next step is to determine the precise nature of the particle and its significance for our understanding of the universe.
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CERN today signed a contract with the Wigner Research Centre for Physics in Budapest for an extension to the CERN data centre. Under the new agreement, the Wigner Centre will host CERN equipment that will substantially extend the capabilities of the LHC Computing Grid Tier-0 activities. This contract is initially until 31 December 2015, with the possibility of up to four one-year extensions thereafter.
(image: event recorded with the CMS detector in 2012 at a proton-proton centre of mass energy of 8TeV)
LHC physics data-taking gets underway at a new record collision energy of 8TeV. The LHC declares "stable beams" as two 4 TeV proton beams are brought into collision at the LHC’s four interaction points. This signals the start of physics data-taking by the LHC experiments for 2012. The collision energy of 8 TeV is a new world record, and increases the machine’s discovery potential considerably.
In a seminar, the ATLAS and CMS experiments present the status of their searches for the Standard Model Higgs boson. Their results are based on the analysis of considerably more data than those presented at the summer conferences, enough to make significant progress in the search for the Higgs boson, but not enough to make any conclusive statement on the existence or non-existence of the elusive Higgs. The main conclusion is that the Standard Model Higgs boson, if it exists, is most likely to have a mass constrained to the range 116-130 GeV by the ATLAS experiment, and 115-127 GeV by CMS.
The grand total of data delivered by the LHC during the year reaches almost six inverse femtobarns. At the beginning of the year’s run, the objective for the LHC was to deliver a quantity of data known to physicists as one inverse femtobarn – approximately 100 trillion (102) proton-proton collisions – during the course of 2011. The first inverse femtobarn came on 17 June, setting the experiments up well for the major physics conferences of the summer and requiring the 2011 data objective to be revised upwards to five inverse femtobarns. This milestone is reached on 18 Octobe
In 2013 IceCube presented two events at around 1 PeV, the first recorded on 9 August 2011, the second on 3 January 2012. Both of these events were part of the search for ultra high energy cosmogenic neutrinos and were completely unexpected. These were the highest neutrino energies to be observed with an equivalent mass energy of over 1 million protons or about 250 times the energy of one of the protons accelerated at the LHC. The neutrinos detected may have originated from Galactic or extragalactic sources of cosmic rays.
In a paper published today in the journal Nature, the Japanese-European ASACUSA experiment at CERN reported a new measurement of the antiproton’s mass accurate to about one part in a billion. Precision measurements of the antiproton mass provide an important way to investigate nature’s apparent preference for matter over antimatter.
The ALPHA experiment at CERN reported today that it succeeded in trapping antimatter atoms for over 16 minutes: long enough to begin to study their properties in detail. ALPHA is part of a broad programme at CERN’s antiproton decelerator investigating the mysteries of one of nature’s most elusive substances.
AMS during tests at the University of Geneva, Switzerland, in 1999 (Image: Laurent Guiraud)
On 18 December 2010, the expanded version of AMANDA, IceCube was completed. IceCube works in the same way as AMANDA but on a larger scale. AMANDA was incorporated into IceCube after operating for nine years. IceCube took seven years to complete and measures Cherenkov light emitted by charged particles produced in neutrino interactions in a cubic kilometer of transparent ice – the water equivalent of one million swimming pools.
(Image: Martin Aleksa, Lyndon Evans, Fabiola Gianotti and Peter Jenni toast running at 7 TeV)
After initial lower energy collision physics from November 2009 onwards, ATLAS records collisions at 7 TeV centre-of-mass energy for the first time. Particle physicists around the world anticipate a rich harvest of new physics as the LHC begins its first long run at an energy three and a half times higher than previously achieved at a particle accelerator.
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After a short technical stop, beams circulate again on 28 February 2010. A month later, on 19 March, two 3.5 TeV proton beams successfully circulate in the Large Hadron Collider for the first time. This is the highest energy yet achieved in a particle accelerator and an important step on the way to the start of the LHC research programme.
The LHC ends its first full period of operation. Collisions at 2.36 TeV set a new world record and bring to a close a successful first run for the world’s most powerful particle accelerator. The LHC is put into standby mode for a short technical stop to prepare for higher energy collisions and the start of the main research programme. Over the 2009 run, each of the LHC’s four major experiments, ALICE, ATLAS, CMS and LHCb recorded more than one million particle collisions, which are distributed for analysis around the world on the LHC computing grid.
Particle beams circulate again in the LHC, the world's most powerful particle accelerator.
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(Image: The ISOLDE beamline, equipped with the first HIE-ISOLDE cryomodule in its light grey cryostat)
The 53rd and final replacement magnet for the Large Hadron Collider (LHC) is lowered into the accelerator tunnel, marking the end of repair work above ground following the incident in September the year before that brought the LHC operations to a halt.
On 13 March 2009, Web inventor Tim Berners-Lee returned to the birthplace of his invention, 20 years after submitting his paper ‘Information Management: A Proposal’ to his boss Mike Sendall. By writing the words ‘Vague, but exciting’ on the document’s cover, and giving Berners-Lee the go-ahead to continue, Sendall was signing into existence the information revolution of our times: the World Wide Web.
CERN today hosted a visit from actors Tom Hanks and Ayelet Zurer and director Ron Howard as they unveiled exclusively some select footage from their new film adaptation of Dan Brown’s novel Angels & Demons, set for worldwide release by Sony Pictures on 15 May 2009.
Read the full Press Release.
The Japanese Vice Minister of Education, Culture, Sports, Science and Technology, T. Yamauchi, draws a second eye on the Daruma doll to mark the completion of the LHC project. In line with Japanese tradition, this Daruma doll, offered to CERN's Director-General in 1995, was painted with one eye at the start of the project.
During powering tests of the main dipole circuit in Sector 3-4 of the LHC, a fault occurs in the electrical bus connection in the region between a dipole and a quadrupole, resulting in mechanical damage and release of helium from the magnet cold mass into the tunnel. Proper safety procedures are in force, the safety systems perform as expected, and no-one is put at risk.
More about the incident:
A full technical analysis of the incident is available here.
At 10.28am on 10 September 2008 a beam of protons is successfully steered around the 27-kilometre Large Hadron Collider (LHC) for the first time. The machine is ready to embark on a new era of discovery at the high-energy frontier.
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The pixel detector barrel is the last large piece of the CMS detector to be lowered into the cavern.
A component known as a small wheel is the last large piece of the ATLAS detector to be lowered into the cavern. The ATLAS detector has the largest volume of any detector ever constructed.
In November 2007, the Auger project published results showing that the direction of origin of the 27 highest energy events were strongly correlated with the location of active galactic nuclei (AGN). An active galactic nucleus is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum.
(Image: ISCOOL, an ion cooler and buncher installed at ISOLDE)
An ion cooler and buncher, ISCOOL, is installed in the HRS section of ISOLDE. Beams with strongly reduced emittances and energy spreads are now available for all experiments downstream the beam line.
The last superconducting magnet is lowered down an access shaft to the LHC. The 15-metre dipoles, each weighing 35 tonnes, are the most complex components of the machine. In total, 1232 dipoles were lowered to 50 metres below the surface via a special oval shaft. They were then taken through a transfer tunnel to their final destination in the LHC tunnel, carried by a specially designed vehicle travelling at 3 kilometres per hour.
The ATLAS Barrel Toroid, a characteristic component of the detector, then the largest superconducting magnet ever built, was switched on for the first time. It works together with the two Endcap Toroids and central Solenoid magnet systems to bend the paths of charged particles produced in collisions at the LHC, enabling important properties to be measured.
The ATLAS Barrel Toroid, then the largest superconducting magnet ever built, was switched on for the first time at CERN on 20 November 2006. The magnet is called the Barrel Toroid because of its barrel-like shape.
It provides a powerful magnetic field for ATLAS, one of the major particle detectors taking data at the Large Hadron Collider (LHC). The magnet consists of eight superconducting coils, each in the shape of a round-cornered rectangle, 5 metres wide, 25m long and weighing 100 tonnes, all aligned to millimetre precision.
After six and a half years of work, CERN leaders and dignitaries celebrate the completion of a second detector cavern. The CMS cavern is 53 x 27 x 24 metres. The construction was delayed by six months after workers unearthed 4th century Gallo-Roman ruins at the work site. Archaeologists found a Gallo-Roman villa with surrounding fields, coins from Ostia (a seaport of Rome), Lyon in France (then Gaul) and London.
CERN celebrated its 50th anniversary in style, with the inauguration of the Globe of Science and Innovation (pictured, under construction) on 19 October. A gift from the Swiss Confederation, the Globe is an iconic wooden structure first used for the Swiss national exhibition in 2002 as a pavilion dedicated to the theme of sustainable development. It was designed by architects Thomas Büchi and Hervé Dessimoz of Geneva. The Globe is being developed into a new visitor and networking centre for the Laboratory — a focal point for CERN’s interaction with society.
(Image: A 3-D drawing of the Class A Lab with a photo inset)
The new Class A building at ISOLDE is built to enable UCx target material to be produced and irradiated targets to be handled safely. The Class A laboratory is equipped with fume cupboards, full protective measures and aerosol monitoring. It can handle 150 g UO2 per day, corresponding to two target containers.
The aim of the European Datagrid project was to produce a "production quality" computing Grid, in anticipation of the construction of the Worldwide LHC Computing Grid. According to the project's website:
The objective is to build the next generation computing infrastructure providing intensive computation and analysis of shared large-scale databases, from hundreds of terabytes to petabytes, across widely distributed scientific communities
The LHC forward collaboration proposes to build two small calorimeters near the ATLAS detector for high-energy cosmic ray research.
Upon completing its 100th surface detector, the Pierre Auger Observatory became the largest cosmic-ray air shower array in the world. The Pierre Auger Observatory is a hybrid detector that uses two independent methods of detecting and studying cosmic rays. The observatory detects high-energy particles through their interaction with water placed in the surface detector tanks. The other method of detection is through tracking the development of air showers through observing the ultraviolet light emitted high in the earth’s atmosphere.
The following is an extract from: "The LHC computing grid project at CERN" (Lamanna, 2004)
The photomultiplier tubes within these basketball-sized glass orbs are at the heart of the AMANDA neutrino telescope, a novel telescope being built at the South Pole to detect cosmic neutrinos (Image: Jeff Miller)
After five years of innovative and ingenious civil engineering, the ATLAS detector cavern (35 x 55 x 40 metres) is fully excavated and ready for the installation of the detector. ATLAS, CERN officials, and political authorities, including the President of the Swiss Confederation Pascal Couchepin, celebrate the inauguration of the first cavern on the LHC on 4 June 2003.
After five years of innovative and ingenious civil engineering, the ATLAS detector cavern (35 x 55 x 40 metres) was fully excavated. ATLAS, CERN officials, and political authorities, including the President of the Swiss Confederation Pascal Couchepin, celebrated the inauguration of the first cavern on the Large Hadron Collider on 4 June 2003. Installation of the detector in the cavern began soon after.
Two CERN experiments, ATHENA and ATRAP, created thousands of atoms of antimatter in a “cold” state in 2002. Cold means that the atoms are slow moving, which makes it possible to study them before they meet ordinary matter and annihilate. Antihydrogen formed in the experiments when cold positrons and antiprotons were brought together and held in a specially designed “trap”. Once formed, the electrically neutral antihydrogen atoms drifted out of the trap and annihilated.
A new accelerator, REX-ISOLDE, is put into operation on 31 October 2001. This post-accelerator has opened up new fields of research using radioactive ion beams of higher energies. REX-ISOLDE can provide post-accelerated nuclei covering the whole mass range from He to U for reaction studies and Coulomb excitation with energies up to 3 MeV/u. To this day, REX has accelerated over 100 isotopes of more than 30 different elements.
The Large Electron-Positron collider was shut down for the last time at 8am on 2 November 2000. Members of government from around the world gathered at CERN on 9 October to celebrate the achievements of LEP and its 11 years of operational life. With the tunnel now available for work, teams began excavating the caverns to house the four big detectors on the Large Hadron Collider.
Bulgaria became a full member state of CERN on 11 June, when it gave UNESCO its instrument of ratification of the constitutive Convention of CERN.
LHCb is the fourth experiment approved for the LHC. The experiment will study the phenomenon known as CP violation, which would help explain why matter dominates antimatter in the universe.
The Monopole and Exotics Detector at the LHC proposes to build a detector to search for highly ionizing particles and slow exotic decays at the LHC. The Letter of Intent marks the first official use of the name MoEDAL. It will be the LHC’s seventh detector.
The Total Cross Section, Elastic Scattering Diffraction Dissociation collaboration proposes to build a detector to measure the basic properties of proton-proton collisions at high energy. The Letter of Intent marks the first official use of the name TOTEM.
Satellite image showing spring ice melt underway on Lake Baikal (Image: NASA Earth Observatory)
NT200, a detector in lake Baikal played a pioneering role in neutrino astronomy. NT200 was constructed between 1993 and 1998. However, in 1994 NT200 detected two neutrino events when only 36 of the final 192 photodetectors were set up. These were the first of several hundred thousand atmospheric neutrinos which NT200 later detected.
The CERN research board officially approves the ALICE experiment. Re-using the L3 magnet experiment from the LEP, ALICE is designed to study quark-gluon plasma, a state of matter that would have existed in the first moments of the universe.
In 1996 CERN's antiproton machines – the Antiproton Accumulator (AC), the Antiproton Collector and the Low Energy Antiproton Ring (LEAR) – were closed down to free resources for the Large Hadron Collider. But a community of antimatter scientists wanted to continue their LEAR experiments with slow antiprotons. Council asked the Proton Synchrotron division to investigate a low-cost way to provide the necessary low-energy beams.
Four years after the first technical proposals, the experiments CMS and ATLAS are officially approved. Both are general-purpose experiments designed to explore the fundamental nature of matter and the basic forces that shape our universe.
The LHC study group publish the LHC Conceptual Design Report, which details the architecture and operation of the LHC. The report follows the CERN Council approval of the LHC project in December 1994.
A team led by Walter Oelert created atoms of antihydrogen for the first time at CERN’s Low Energy Antiproton Ring (LEAR) facility. Nine of these atoms were produced in collisions between antiprotons and xenon atoms over a period of 3 weeks. Each one remained in existence for about 40 billionths of a second, travelled at nearly the speed of light over a path of 10 metres and then annihilated with ordinary matter. The annihilation produced the signal that showed that the anti-atoms had been created.
Industrial robots are installed for manipulation of ISOLDE targets, which allows all target changes and manipulations of used target-ion-source systems to be made without human intervention.
The CERN council approves the construction of the Large Hadron Collider. To achieve the project without enlarging CERN’s budget, they decide to build the accelerator in two stages.
ATLAS submitted the technical proposal of the experiment to the LHC Experiments Committee. Approval to proceed with technical design reports was granted in early 1996, followed by the submission of the first report on 15 December of the same year. A long series of technical design reports have been submitted since then. In July 1997, the Committee approved the construction of the ATLAS detector. Teams all over the world built detector components and worked on final technical developments.
The first prototype bending-magnet for the LHC reaches a field of 8.73 Tesla. The LHC will operate in 2012 with 8.4 Tesla field, which is 100,000 times more powerful than the earth's magnetic field.
On 3 December 1993, the Akeno Giant Air Shower Array (AGASA) recorded a cosmic ray with an energy of 2x1020 eV. This was a particularly well-measured event because the cosmic rays fell completely inside the detector array and arrived from a nearly vertical direction. This was the highest energy cosmic ray observed at AGASA and greatly exceeded that of any known source.
Due to concerns linked to rising costs, the US government votes to cancel the Superconducting Super Collider (SSC) project in Waxahachie, Texas. The SSC – a circular accelerator with an 87-kilometre circumference designed to smash particles at 40 TeV centre-of-mass energy – would have been far more powerful than CERN's LHC. The LHC is now the sole candidate for a new high energy hadron collider.
The Czech Republic joins
Statement of the government of the Czech Republic on questions of membership in International Governmental Organizations:
On 30 April 1993 CERN issued a statement putting the Web into the public domain, ensuring that it would remain an open standard. The organization released the source code of Berners-Lee's hypertext project, WorldWideWeb, into the public domain the same day. WorldWideWeb became free software, available to all. The move had an immediate effect on the spread of the web. By late 1993 there are over 500 known web servers, and the web accounts for 1% of internet traffic.
By a letter dated 16 December 1992, the Permanent Mission of the Czech and Slovak Federal Republic (CSFR) to the United Nations in Geneva informed CERN that the Czech and Slovak Federal Republic would cease to exist on 31 December 1992 and that two new states – the Czech Republic and the Slovak Republic – would succeed it as from 1 January 1993.
The letter states:
The A Toroidal LHC Apparatus (ATLAS) collaboration propose to build a multipurpose detector at the LHC. The Letter of Intent they submit to the LHC Experiments Committee marks the first official use of the name ATLAS. Two collaborations called ASCOT and EAGLE combine to form ATLAS.
The A Toroidal LHC ApparatuS (ATLAS) collaboration proposed to build a general-purpose detector at the LHC, an idea born in the 1980s. The Letter of Intent was submitted to the LHC Experiments Committee, which marked the first official use of the name ATLAS.