Large Electron Positron Accelerator

Copper radiofrequency cavity used in the Large Electron Positron (LEP) Accelerator, made by CERN in Geneva, Switzerland, in approx 1988-89

The Large Electron-Positron Collider was one of the largest particle accelerators ever built. LEP collided electrons with positrons and four large detectors, ALEPH, DELPHI, L3, and OPAL, observed and recorded the results of these collisions. LEP consisted of 5176 magnets and 128 accelerating cavities. LEP was commissioned in 1898 and the first beam circulated in the collider on 14th July. After eleven years of experiments LEP was closed down to make way for the construction of the Large Hadron Collider.

The collider is pictured on display at the Collider exhibition in the basement of the Wellcome Wing at the Science Museum, London, in 2013. The exhibition explored the discovery of the Higgs boson, first theorised by physicist Professor Peter Higgs, at CERN in Switzerland. The exhibition contained items of the Large Hadron Collider as well as videos of scientists, drawings of the collider and parts of the machinery which works the collider.