The European Organization for Nuclear Research (Organisation Européenne pour la Recherche Nucléaire), known as CERN (see Naming), (sɛʀn in French), is the world's largest particle physics laboratory, situated in the northwest suburbs of Geneva on the Franco-Swiss border, established in 1954. The organization has twenty European member states, and is currently the workplace of approximately 2600 full-time employees, as well as some 7931 scientists and engineers (representing 500 universities and 80 nationalities).
CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research. Numerous experiments have been constructed at CERN by international collaborations to make use of them. The main site at Meyrin also has a large computer centre containing very powerful data processing facilities primarily for experimental data analysis, and because of the need to make them available to researchers elsewhere, has historically been (and continues to be) a major wide area networking hub.
As an international facility, the CERN sites are officially under neither Swiss nor French jurisdiction. Member states' contributions to CERN for the year 2008 totalled CHF 1 billion (approximately €664 million, US$ 1 billion).
Soon after its establishment, the work at the laboratory went beyond the study of the atomic nucleus, into higher-energy physics, an activity which is mainly concerned with the study of interactions between 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 current research being performed at CERN.
The World Wide Web began as a CERN project called ENQUIRE, initiated by Sir Tim Berners-Lee and Robert Cailliau in 1989. Berners-Lee and Cailliau were jointly honored by the ACM in 1995 for their contributions to the development of the World Wide Web.
Based on the concept of hypertext, the project was aimed at facilitating sharing information among researchers. The first website went on-line in 1991. On 30 April 1993, CERN announced that the World Wide Web would be free to anyone. A copy of the original first webpage, created by Berners-Lee, is still published on the World Wide Web Consortium website as a historical document.
More recently, CERN has become a centre for the development of Grid computing, hosting among others the Enabling Grids for E-sciencE (EGEE) and LHC Computing Grid projects. It also hosts the CERN Internet Exchange Point (CIXP), one of the two main Internet Exchange Points in Switzerland. CERN's computer network is connected to JANET (formerly UKERNA), the research and education network, JANET aids CERN to disperse large data over a network grid for closer analysis.
CERN operates a network of six accelerators and a decelerator. Each machine in the chain increases the energy of particle beams before delivering them to experiments or to the next more powerful accelerator. Currently active machines are:
The LHC tunnel is located 100 metres underground, in the region between the Geneva airport and the nearby Jura mountains. It uses the 27 km circumference circular tunnel previously occupied by LEP which was closed down in November 2000. CERN's existing PS/SPS accelerator complexes will be used to pre-accelerate protons which will then be injected into the LHC.
Six experiments (CMS, ATLAS, LHCb, TOTEM, LHC-forward and ALICE) are currently being built, and will be running on the collider; each of them will study particle collisions under a different point of view, and with different technologies. Construction for these experiments required an extraordinary engineering effort. Just as an example, to lower the pieces for the CMS experiment into the underground cavern which will host it, a special crane will have to be rented from Belgium, which will be able to lift the almost 2000 tons for each piece. 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.
This accelerator will generate vast quantities of computer data, which CERN will stream to laboratories around the world for distributed processing (making use of a specialised GRID infrastructure, the LHC Computing Grid). In April 2005, a trial successfully streamed 600 MB per second to seven different sites across the world. If all the data generated by the LHC is to be analysed, then scientists must achieve 1,800 MB per second before 2008.
The initial particle beams were injected into the LHC August 2008, the first attempt to circulate a beam through the entire LHC was at 0830Z on 10 September 2008, but the system was taken down for repairs on 19 September 2008 and due to a faulty magnet it must be reheated, repaired, and recooled. With this and the previously scheduled winter shutoff due to power consumption, no results are expected before February 2009.
The smaller accelerators are located 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 so there is no obvious border within the site, apart from a line of marker stones. There are six entrances to the Meyrin site:
The SPS and LEP/LHC tunnels are located underground 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 themselves 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 which will be used for 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 charmed particles and located at the Prévessin (North Area) site while WA22 used the BEBC bubble chamber 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.
The original twelve CERN signatories from 1954 were:
All founding members have so far (as of 2008) remained in the CERN organisation, except Yugoslavia which left in 1961 and never re-joined.
Since its foundation, CERN regularly accepted new members. All new members have remained in the organisation continuously since their acceptance, except Spain which joined in 1961, withdrew eight years later, and joined anew in 1983. CERN's membership history is as follows:
There are currently twenty member countries, 18 of which are also European Union member states.
Eight additional international organizations or countries have "observer status":
Facilities at CERN open to the public include: