CERN

CERN is the European Organization for Nuclear Research (Organisation Européenne pour la Recherche Nucléaire), the world's largest particle physics laboratory, situated on the border between France and Switzerland, just west of Geneva. It is also known for being the birthplace of the World Wide Web. The convention establishing it was signed on September 29, 1954. From the original 12 signatories of the CERN convention, membership has grown to the present 20 Member States.

CERN sites

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 since been extended to span the border. 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:

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• A, in Switzerland. Open for all CERN personnel at specific times.
• B, in Switzerland. Open for all CERN personnel 24/7. Often referred to as the main entrance
• C, in Switzerland. Open for all CERN personnel at specific times.
• D, in Switzerland. Open for goods reception at specific times.
• E, in France. Open for all CERN personnel at specific times. Controlled by customs personnel.
• Tunnel entrance, in France. Open for equipment transfer to and from CERN sites in France by personnel with a specific permit. This is the only permitted route for such transfers. Under the CERN treaty, no taxes are payable when such transfers are made. Controlled by customs personnel.

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 plant and access shafts. The experiments themselves are located at the same underground level as the tunnels at these sites.

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All of these experimental sites are in France, 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).

Related Topics:
UA1 - UA2

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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 whilst 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.

Related Topics:
Charm - Prévessin - BEBC

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