Cern

Established in 1954, it is based in Meyrin, western suburb of Geneva, on the France–Switzerland border. It comprises 23 member states. Israel, admitted in 2013, is the only non-European full member. CERN is an official United Nations General Assembly observer.

European Organization for Nuclear Research

Organisation européenne pour la recherche nucléaire
Wiki English
Wiki English CERN's main site in Meyrin, Switzerland, looking towards the French border
Wiki English States with full CERN membership
Formation	29 September 1954; 69 years ago (1954-09-29)
Headquarters	Meyrin, Geneva, Switzerland 46°14′03″N 6°03′10″E / 46.23417°N 6.05278°E / 46.23417; 6.05278
Membership	Full members (23):  Austria  Belgium  Bulgaria  Czech Republic  Denmark  Finland  France  Germany  Greece  Hungary  Israel  Italy  Netherlands  Norway  Poland  Portugal  Romania  Serbia  Slovakia  Spain  Sweden   Switzerland  United Kingdom Associate members (11):  Brazil  Croatia  Cyprus  Estonia  India  Latvia  Lithuania  Pakistan  Slovenia  Turkey  Ukraine
Official languages	English and French
Council President	Eliezer Rabinovici
Director-General	Fabiola Gianotti
Budget (2022)	1405m CHF
Website	home.cern

The acronym CERN is also used to refer to the laboratory; in 2019, it had 2,660 scientific, technical, and administrative staff members, and hosted about 12,400 users from institutions in more than 70 countries. In 2016, CERN generated 49 petabytes of data.

CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research – consequently, numerous experiments have been constructed at CERN through international collaborations. CERN is the site of the Large Hadron Collider (LHC), the world's largest and highest-energy particle collider. The main site at Meyrin hosts a large computing facility, which is primarily used to store and analyze data from experiments, as well as simulate events. As researchers require remote access to these facilities, the lab has historically been a major wide area network hub. CERN is also the birthplace of the World Wide Web.

 

The convention establishing CERN was ratified on 29 September 1954 by 12 countries in Western Europe. The acronym CERN originally represented the French words for Conseil Européen pour la Recherche Nucléaire ('European Council for Nuclear Research'), which was a provisional council for building the laboratory, established by 12 European governments in 1952. During these early years, the council worked at the University of Copenhagen under the direction of Niels Bohr before moving to its present site near Geneva. The acronym was retained for the new laboratory after the provisional council was dissolved, even though the name changed to the current Organisation Européenne pour la Recherche Nucléaire ('European Organization for Nuclear Research') in 1954. According to Lew Kowarski, a former director of CERN, when the name was changed, the abbreviation could have become the awkward OERN, and Werner Heisenberg said that this could "still be CERN even if the name is [not]".

CERN's first president was Sir Benjamin Lockspeiser. Edoardo Amaldi was the general secretary of CERN at its early stages when operations were still provisional, while the first Director-General (1954) was Felix Bloch.

The laboratory was originally devoted to the study of atomic nuclei, but was soon applied to higher-energy physics, concerned mainly with the study of interactions between subatomic particles. Therefore, the laboratory operated by CERN is commonly referred to as the European laboratory for particle physics (Laboratoire européen pour la physique des particules), which better describes the research being performed there.^{[citation needed]}

Founding members

At the sixth session of the CERN Council, which took place in Paris from 29 June to 1 July 1953, the convention establishing the organization was signed, subject to ratification, by 12 states. The convention was gradually ratified by the 12 founding Member States: Belgium, Denmark, France, the Federal Republic of Germany, Greece, Italy, the Netherlands, Norway, Sweden, Switzerland, the United Kingdom, and Yugoslavia.

Scientific achievements

Several important achievements in particle physics have been made through experiments at CERN. They include:

• 1973: The discovery of neutral currents in the Gargamelle bubble chamber;
• 1983: The discovery of W and Z bosons in the UA1 and UA2 experiments;
• 1989: The determination of the number of light neutrino families at the Large Electron–Positron Collider (LEP) operating on the Z boson peak;
• 1995: The first creation of antihydrogen atoms in the PS210 experiment;
• 1995–2005: Precision measurement of the Z lineshape, based predominantly on LEP data collected on the Z resonance from 1990 to 1995;
• 1999: The discovery of direct CP violation in the NA48 experiment;
• 2000: The Heavy Ion Programme discovered a new state of matter, the Quark Gluon Plasma.
• 2010: The isolation of 38 atoms of antihydrogen;
• 2011: Maintaining antihydrogen for over 15 minutes;
• 2012: A boson with mass around 125 GeV/c² consistent with the long-sought Higgs boson.

In September 2011, CERN attracted media attention when the OPERA Collaboration reported the detection of possibly faster-than-light neutrinos. Further tests showed that the results were flawed due to an incorrectly connected GPS synchronization cable.

The 1984 Nobel Prize for Physics was awarded to Carlo Rubbia and Simon van der Meer for the developments that resulted in the discoveries of the W and Z bosons. The 1992 Nobel Prize for Physics was awarded to CERN staff researcher Georges Charpak "for his invention and development of particle detectors, in particular the multiwire proportional chamber". The 2013 Nobel Prize for Physics was awarded to François Englert and Peter Higgs for the theoretical description of the Higgs mechanism in the year after the Higgs boson was found by CERN experiments.

Computer science

 

This NeXT Computer used by British scientist Sir Tim Berners-Lee at CERN became the first Web server.

 

This Cisco Systems router at CERN was one of the first IP routers deployed in Europe.

 

A plaque at CERN commemorating the invention of the World Wide Web by Tim Berners-Lee and Robert Cailliau

CERN pioneered the introduction of Internet technology, beginning in the early 1980s. This played an influential role in the adoption of the TCP/IP in Europe (see Protocol Wars).

The World Wide Web began as a project at CERN initiated by Tim Berners-Lee in 1989. This stemmed from his earlier work on a database named ENQUIRE. Robert Cailliau became involved in 1990. Berners-Lee and Cailliau were jointly honoured by the Association for Computing Machinery in 1995 for their contributions to the development of the World Wide Web. A copy of the original first webpage, created by Berners-Lee, is still published on the World Wide Web Consortium's website as a historical document.

Based on the concept of hypertext, the project was designed to facilitate the sharing of information between researchers. The first website was activated in 1991. On 30 April 1993, CERN announced that the World Wide Web would be free to anyone. It became the dominant way through which most users interact with the Internet.

More recently, CERN has become a facility for the development of grid computing, hosting projects including the Enabling Grids for E-sciencE (EGEE) and LHC Computing Grid. It also hosts the CERN Internet Exchange Point (CIXP), one of the two main internet exchange points in Switzerland. As of 2022^[update], CERN employs ten times more engineers and technicians than research physicists.

Current complex

CERN Complex

Current particle and nuclear facilities
LHC	Accelerates protons and heavy ions
LEIR	Accelerates ions
SPS	Accelerates protons and ions
PSB	Accelerates protons
PS	Accelerates protons or ions
Linac 3	Injects heavy ions into LEIR
Linac4	Accelerates ions
AD	Decelerates antiprotons
ELENA	Decelerates antiprotons
ISOLDE	Produces radioactive ion beams
MEDICIS	Produces isotopes for medical purposes

 

CERN operates a network of seven accelerators and two decelerators, and some additional small accelerators. Each machine in the chain increases the energy of particle beams before delivering them to experiments or to the next more powerful accelerator (the decelerators naturally decrease the energy of particle beams before delivering them to experiments or further accelerators/decelerators). Before an experiment is able to use the network of accelerators, it must be approved by the various Scientific Committees of CERN. Currently (as of 2022) active machines are the LHC accelerator and:

• The LINAC 3 linear accelerator generating low energy particles. It provides heavy ions at 4.2 MeV/u for injection into the Low Energy Ion Ring (LEIR).
• The Low Energy Ion Ring (LEIR) accelerates the ions from the ion linear accelerator LINAC 3, before transferring them to the Proton Synchrotron (PS). This accelerator was commissioned in 2005, after having been reconfigured from the previous Low Energy Antiproton Ring (LEAR).
• The Linac4 linear accelerator accelerates negative hydrogen ions to an energy of 160 MeV. The ions are then injected to the Proton Synchrotron Booster (PSB) where both electrons are then stripped from each of the hydrogen ions and thus only the nucleus containing one proton remains. The protons are then used in experiments or accelerated further in other CERN accelerators. Linac4 serves as the source of all proton beams for CERN experiments.
• The Proton Synchrotron Booster increases the energy of particles generated by the proton linear accelerator before they are transferred to the other accelerators.
• The 28 GeV Proton Synchrotron (PS), built during 1954–1959 and still operating as a feeder to the more powerful SPS and to many of CERN's experiments.
• The Super Proton Synchrotron (SPS), a circular accelerator with a diameter of 2 kilometres built in a tunnel, which started operation in 1976. It was designed to deliver an energy of 300 GeV and was gradually upgraded to 450 GeV. As well as having its own beamlines for fixed-target experiments (currently COMPASS and NA62), it has been operated as a proton–antiproton collider (the SppS collider), and for accelerating high energy electrons and positrons which were injected into the Large Electron–Positron Collider (LEP). Since 2008, it has been used to inject protons and heavy ions into the Large Hadron Collider (LHC).
• The On-Line Isotope Mass Separator (ISOLDE), which is used to study unstable nuclei. The radioactive ions are produced by the impact of protons at an energy of 1.0–1.4 GeV from the Proton Synchrotron Booster. It was first commissioned in 1967 and was rebuilt with major upgrades in 1974 and 1992.
• The Antiproton Decelerator (AD), which reduces the velocity of antiprotons to about 10% of the speed of light for research of antimatter. The AD machine was reconfigured from the previous Antiproton Collector (AC) machine.
• The Extra Low Energy Antiproton ring (ELENA), which takes antiprotons from AD and decelerates them into low energies (speeds) for use in antimatter experiments.
• The AWAKE experiment, which is a proof-of-principle plasma wakefield accelerator.
• The CERN Linear Electron Accelerator for Research (CLEAR) accelerator research and development facility.

Large Hadron Collider

Many activities at CERN currently involve operating the Large Hadron Collider (LHC) and the experiments for it. The LHC represents a large-scale, worldwide scientific cooperation project.

 

The LHC tunnel is located 100 metres underground, in the region between Geneva International Airport and the nearby Jura mountains. The majority of its length is on the French side of the border. It uses the 27 km circumference circular tunnel previously occupied by the Large Electron–Positron Collider (LEP), which was shut down in November 2000. CERN's existing PS/SPS accelerator complexes are used to pre-accelerate protons and lead ions which are then injected into the LHC.

Eight experiments (CMS, ATLAS, LHCb, MoEDAL, TOTEM, LHCf, FASER and ALICE) are located along the collider; each of them studies particle collisions from a different aspect, and with different technologies. Construction for these experiments required an extraordinary engineering effort. For example, a special crane was rented from Belgium to lower pieces of the CMS detector into its cavern, since each piece weighed nearly 2,000 tons. The first of the approximately 5,000 magnets necessary for construction was lowered down a special shaft at 13:00 GMT on 7 March 2005.

The LHC has begun to generate vast quantities of data, which CERN streams to laboratories around the world for distributed processing (making use of a specialized grid infrastructure, the LHC Computing Grid). During April 2005, a trial successfully streamed 600 MB/s to seven different sites across the world.

The initial particle beams were injected into the LHC August 2008. The first beam was circulated through the entire LHC on 10 September 2008, but the system failed 10 days later because of a faulty magnet connection, and it was stopped for repairs on 19 September 2008.

The LHC resumed operation on 20 November 2009 by successfully circulating two beams, each with an energy of 3.5 teraelectronvolts (TeV). The challenge for the engineers was then to line up the two beams so that they smashed into each other. This is like "firing two needles across the Atlantic and getting them to hit each other" according to Steve Myers, director for accelerators and technology.

On 30 March 2010, the LHC successfully collided two proton beams with 3.5 TeV of energy per proton, resulting in a 7 TeV collision energy. However, this was just the start of what was needed for the expected discovery of the Higgs boson. When the 7 TeV experimental period ended, the LHC revved to 8 TeV (4 TeV per proton) starting March 2012, and soon began particle collisions at that energy. In July 2012, CERN scientists announced the discovery of a new sub-atomic particle that was later confirmed to be the Higgs boson.

In March 2013, CERN announced that the measurements performed on the newly found particle allowed it to conclude that it was a Higgs boson. In early 2013, the LHC was deactivated for a two-year maintenance period, to strengthen the electrical connections between magnets inside the accelerator and for other upgrades.

On 5 April 2015, after two years of maintenance and consolidation, the LHC restarted for a second run. The first ramp to the record-breaking energy of 6.5 TeV was performed on 10 April 2015. In 2016, the design collision rate was exceeded for the first time. A second two-year period of shutdown begun at the end of 2018.

Accelerators under construction

As of October 2019, the construction is on-going to upgrade the LHC's luminosity in a project called High Luminosity LHC (HL–LHC). This project should see the LHC accelerator upgraded by 2026 to an order of magnitude higher luminosity.

As part of the HL–LHC upgrade project, also other CERN accelerators and their subsystems are receiving upgrades. Among other work, the LINAC 2 linear accelerator injector was decommissioned and replaced by a new injector accelerator, the LINAC4.

Decommissioned accelerators

• The original linear accelerator LINAC 1. Operated 1959–1992.
• The LINAC 2 linear accelerator injector. Accelerated protons to 50 MeV for injection into the Proton Synchrotron Booster (PSB). Operated 1978–2018.
• The 600 MeV Synchro-Cyclotron (SC) which started operation in 1957 and was shut down in 1991. Was made into a public exhibition in 2012–2013.
• The Intersecting Storage Rings (ISR), an early collider built from 1966 to 1971 and operated until 1984.
• The Super Proton–Antiproton Synchrotron (SppS), operated 1981–1991. A modification of Super Proton Synchrotron (SPS) to operate as a proton-antiproton collider.
• The Large Electron–Positron Collider (LEP), which operated 1989–2000 and was the largest machine of its kind, housed in a 27 km-long circular tunnel which now houses the Large Hadron Collider.
• The LEP Pre-Injector (LPI) accelerator complex, consisting of two accelerators, a linear accelerator called LEP Injector Linac (LIL; itself consisting of two back-to-back linear accelerators called LIL V and LIL W) and a circular accelerator called Electron Positron Accumulator (EPA). The purpose of these accelerators was to inject positron and electron beams into the CERN accelerator complex (more precisely, to the Proton Synchrotron), to be delivered to LEP after many stages of acceleration. Operational 1987–2001; after the shutdown of LEP and the completion of experiments that were directly fed by the LPI, the LPI facility was adapted to be used for the CLIC Test Facility 3 (CTF3).
• The Low Energy Antiproton Ring (LEAR) was commissioned in 1982. LEAR assembled the first pieces of true antimatter, in 1995, consisting of nine atoms of antihydrogen. It was closed in 1996, and superseded by the Antiproton Decelerator. The LEAR apparatus itself was reconfigured into the Low Energy Ion Ring (LEIR) ion booster.
• The Antiproton Accumulator (AA), built 1979–1980, operations ended in 1997 and the machine was dismantled. Stored antiprotons produced by the Proton Synchrotron (PS) for use in other experiments and accelerators (for example the ISR, SppS and LEAR). For later half of its working life operated in tandem with Antiproton Collector (AC), to form the Antiproton Accumulation Complex (AAC).
• The Antiproton Collector (AC), built 1986–1987, operations ended in 1997 and the machine was converted into the Antiproton Decelerator (AD), which is the successor machine for Low Energy Antiproton Ring (LEAR). Operated in tandem with Antiproton Accumulator (AA) and the pair formed the Antiproton Accumulation Complex (AAC), whose purpose was to store antiprotons produced by the Proton Synchrotron (PS) for use in other experiments and accelerators, like the Low Energy Antiproton Ring (LEAR) and Super Proton–Antiproton Synchrotron (SppS).
• The Compact Linear Collider Test Facility 3 (CTF3), which studied feasibility for the future normal conducting linear collider project (the CLIC collider). In operation 2001–2016. One of its beamlines has been converted, from 2017 on, into the new CERN Linear Electron Accelerator for Research (CLEAR) facility.

Possible future accelerators

CERN, in collaboration with groups worldwide, is investigating two main concepts for future accelerators: A linear electron-positron collider with a new acceleration concept to increase the energy (CLIC) and a larger version of the LHC, a project currently named Future Circular Collider.

 

 

The smaller accelerators are on the main Meyrin site (also known as the West Area), which was originally built in Switzerland alongside the French border, but has been extended to span the border since 1965. The French side is under Swiss jurisdiction and there is no obvious border within the site, apart from a line of marker stones.

The SPS and LEP/LHC tunnels are almost entirely outside the main site, and are mostly buried under French farmland and invisible from the surface. However, they have surface sites at various points around them, either as the location of buildings associated with experiments or other facilities needed to operate the colliders such as cryogenic plants and access shafts. The experiments are located at the same underground level as the tunnels at these sites.

Three of these experimental sites are in France, with ATLAS in Switzerland, although some of the ancillary cryogenic and access sites are in Switzerland. The largest of the experimental sites is the Prévessin site, also known as the North Area, which is the target station for non-collider experiments on the SPS accelerator. Other sites are the ones which were used for the UA1, UA2 and the LEP experiments (the latter are used by LHC experiments).

Outside of the LEP and LHC experiments, most are officially named and numbered after the site where they were located. For example, NA32 was an experiment looking at the production of so-called "charmed" particles and located at the Prévessin (North Area) site while WA22 used the Big European Bubble Chamber (BEBC) at the Meyrin (West Area) site to examine neutrino interactions. The UA1 and UA2 experiments were considered to be in the Underground Area, i.e. situated underground at sites on the SPS accelerator.

Most of the roads on the CERN Meyrin and Prévessin sites are named after famous physicists, such as Wolfgang Pauli, who pushed for CERN's creation. Other notable names are Richard Feynman, Albert Einstein, and Bohr.

Member states and budget

Since its foundation by 12 members in 1954, CERN regularly accepted new members. All new members have remained in the organization continuously since their accession, except Spain and Yugoslavia. Spain first joined CERN in 1961, withdrew in 1969, and rejoined in 1983. Yugoslavia was a founding member of CERN but quit in 1961. Of the 23 members, Israel joined CERN as a full member on 6 January 2014, becoming the first (and currently only) non-European full member.

The budget contributions of member states are computed based on their GDP.

Member state	Status since	Contribution (million CHF for 2019)	Contribution (fraction of total for 2019)	Contribution per capita (CHF/person for 2017)
Founding Members
Belgium	29 September 1954	30.7	2.68%	2.7
Denmark	29 September 1954	20.5	1.79%	3.4
France	29 September 1954	160.3	14.0%	2.4
Germany	29 September 1954	236.0	20.6%	2.8
Greece	29 September 1954	12.5	1.09%	1.6
Italy	29 September 1954	118.4	10.4%	2.1
Netherlands	29 September 1954	51.8	4.53%	3.0
Norway	29 September 1954	28.3	2.48%	5.4
Sweden	29 September 1954	30.5	2.66%	3.0
Switzerland	29 September 1954	47.1	4.12%	4.9
United Kingdom	29 September 1954	184.0	16.1%	2.8
Yugoslavia	29 September 1954	0	0%	0.0
Acceded Members
Austria	1 June 1959	24.7	2.16%	2.9
Spain	1 January 1983	80.7	7.06%	2.0
Portugal	1 January 1986	12.5	1.09%	1.3
Finland	1 January 1991	15.1	1.32%	2.8
Poland	1 July 1991	31.9	2.79%	0.8
Hungary	1 July 1992	7.0	0.609%	0.7
Czech Republic	1 July 1993	10.9	0.950%	1.1
Slovakia	1 July 1993	5.6	0.490%	1.0
Bulgaria	11 June 1999	3.4	0.297%	0.4
Israel	6 January 2014	19.7	1.73%	2.7
Romania	17 July 2016	12.0	1.05%	0.6
Serbia	24 March 2019	2.5	0.221%	0.1
Associate Members in the pre-stage to membership
Cyprus	1 April 2016	1.0	N/A	N/A
Slovenia	4 July 2017	1.0	N/A	N/A
Estonia	1 February 2021	1.0	N/A	N/A
Associate Members
Turkey	6 May 2015	5.7	N/A	N/A
Pakistan	31 July 2015	1.7	N/A	N/A
Ukraine	5 October 2016	1.0	N/A	N/A
India	16 January 2017	13.8	N/A	N/A
Lithuania	8 January 2018	1.0	N/A	N/A
Croatia	10 October 2019	0.25	N/A	N/A
Latvia	2 August 2021		N/A	N/A
Brazil	13 March 2024		N/A	N/A
Total Members, Candidates and Associates		1,171.2	100.0%	N/A