What Is CERN?

CERN, formally the European Organization for Nuclear Research, is an intergovernmental research laboratory near Geneva that operates the world's largest particle accelerator complex on behalf of its member states. The acronym comes from the provisional body set up in 1952, the Conseil Européen pour la Recherche Nucléaire, and it stuck even after the permanent organization took a different name. Its scientific mandate is fundamental physics: understanding what matter is made of and what forces hold it together.

The organization was founded on a political premise as much as a scientific one. Twelve European states signed the founding convention in 1953, and it entered into force on 29 September 1954, creating an institution that would pool resources for machines no single country could afford and give European researchers a shared civilian venue after the war. The CERN history record traces that origin, and membership has since expanded well beyond the founding group to include states such as Israel, Romania, Serbia, Estonia, and Slovenia.

Governance and Membership

CERN is governed by a Council on which each member state holds one vote, with delegations drawn from both government administration and the national scientific community. The Council approves the budget, sets the scientific program, and appoints the Director-General, who runs the laboratory day to day. Alongside full members, the organization maintains associate member status, observer arrangements for organizations such as UNESCO and the European Commission, and cooperation agreements with dozens of non-member states. That structure lets roughly 17,000 people from more than 100 nationalities use the facilities while a much smaller staff operates them.

The Accelerator Complex

CERN's accelerators are arranged as a chain, each machine boosting particles before injecting them into the next. Protons begin in a linear accelerator, pass through the Proton Synchrotron Booster, the Proton Synchrotron, and the Super Proton Synchrotron, and finally enter the Large Hadron Collider, a 27-kilometer ring of superconducting dipole magnets cooled to 1.9 kelvin. The LHC first circulated beam on 10 September 2008 and collides protons or heavy ions at energies in the multi-TeV range. Other facilities serve different purposes: the Antiproton Decelerator supports antimatter spectroscopy, ISOLDE produces radioactive isotope beams, and n_TOF provides neutron time-of-flight measurements.

Detectors and Experiments

Four large detectors sit at the LHC collision points. ATLAS and CMS are general-purpose instruments built by independent collaborations so that any discovery can be confirmed twice with different technology, and their joint announcement of a Higgs boson candidate in July 2012 is the laboratory's best-known result. ALICE studies the quark-gluon plasma formed in lead-ion collisions, and LHCb examines the small asymmetries between matter and antimatter in decays of beauty hadrons. Each detector layers silicon tracking, calorimetry, and muon chambers around the beam pipe, generating raw data rates that must be reduced by hardware and software trigger stages before anything is written to storage.

Computing and Engineering Spinoffs

The engineering demands of particle physics have produced technology used far outside it. The World Wide Web began at CERN with Tim Berners-Lee's 1989 proposal for an internet-based hypertext system, and CERN placed the software in the public domain on 30 April 1993. Data handling for the LHC is distributed through the Worldwide LHC Computing Grid, which federates computing centers across dozens of countries into a tiered storage and analysis system. Detector work has also advanced silicon pixel sensors, superconducting magnet fabrication, cryogenics, and radiation-hard electronics.

Applications

Work carried out at CERN has applications in a wide range of fields, including:

• Distributed and grid computing infrastructure
• Medical imaging and hadron therapy for cancer treatment
• Superconducting magnet and cryogenic system design
• Radiation-tolerant semiconductor electronics
• Vacuum technology and materials science
• Large-scale international research project management