Large Electronâ€“Positron Collider
The Large Electron-Positron Collider (LEP, German designation Large Electron-Positron Storage Ring ) was a particle accelerator at the European Organization for Nuclear Research CERN in Geneva.
He was in operation from 1989 to 2000 and served as a collider for electrons and positrons with center of mass energies of up to 209 GeV in the final stage LEP2 (see also Colliding Beam Experiment). ALEPH, Delphi, L3 and OPAL, which provided some important scientific discoveries in the eleven years of operation: On him four large experiments were in operation with them the exact mass of the W and Z bosons was determined and proved that exactly three light neutrinos exist.
The LEP had a circumference of 27 kilometers and was 50-175 meters below the surface in a tunnel at the border between Switzerland and France. The tunnel was converted to operate in it as of 2008 the successor of the LEP, the Large Hadron Collider can. On 10 September 2008, the operation of the new plant was added.