LEP

: The LEP spectrometer: this photo of the inside of the LEP accelerator tunnel shows a special dipole magnet used to measure the energy of the various particles.

Until recently, four experiments were in progress at the Large Electron Positron accelerator (LEP) at CERN, Geneva. With a circumference of 27 kilometres, LEP was the largest machine in the world used to allow electrons and their antiparticles, positrons, to collide. Four large detectors studied the physical aspects of the strong and weak forces down to the smallest detail.

During LEP's 12 years of service, the Standard Model was tested with the help of these experiments. The four LEP experiments were ALEPH, DELPHI, OPAL and L3. Nikhef participated in DELPHI and L3. The tunnel that housed LEP is now used for its successor, the Large Hadron Collider (LHC).