The Titans of CERN

Operational since 2009 and buried 100 m under the Franco-Swiss border, the 27-kilometre Large Hadron Collider (LHC) accelerates two particle beams travelling in opposite directions.

Particle collisions occur where the beams interact, at four specific locations where the giant detectors Alice, Atlas, CMS and LHCb, are installed.

CERN’s first accelerator, the 600 MeV Synchrocyclotron (SC) comes into operation in 1957. It will provide beams for CERN’s first particle and nuclear physics experiments until 1990.

The ring-shaped Proton Synchrotron (PS), which becomes operational in 1960, is the most powerful proton accelerator of its time. Still active today, it continues to supply particle beams to the Large Hadron Collider (LHC).

Since 1967, the Isolde facility produces unstable radioactive nuclei. Their study is useful to nuclear physics, medicine, and electronics.

During the 1950s and 1960s, bubble chambers allowed scientists to observe particle trajectory. One of these was CERN’s Big European Bubble Chamber, used in the 1970s. Particles generate bubbles as they pass through liquid hydrogen maintained at close to boiling point.

In 1968, Nobel prizewinner Georges Charpak (left) brings particle detection into the electronic age with the “multi-wire proportional chamber” (MWPC), which allows for a 1000-fold increase in detection rate.

The Intersecting Storage Rings (ISR), the first proton collider in the world, will operate between 1971 and 1989. Made up of two identical 300-meter rings that intersect at 8 points, the machine, whose beams are supplied by the Proton Synchrotron (PS), allowed scientists to determine that protons were made up of smaller particles.

This bubble chamber, called Gargamelle due to its very large size, detected "weak neutral currents" in 1973, a crucial phenomenon for understanding the world of particles. The experiment uses a beam of neutrinos, very elusive particles that are very sensitive to this phenomenon.

Completed in 1976, the 7km-long Super Proton Synchrotron (SPS) was the first giant underground ring to cross the Franco-Swiss border. Today, it accelerates particles before feeding them to the LHC.

In 1983, CERN announces the discovery by the UA1 (pictured) and UA2 detectors, of the W and Z bosons, which mediate the weak fundamental force on particles.

In operation from 1989 to 2000, the Grand electron-positron collider (LEP) was installed in a tunnel 27 kilometers dug for the occasion, one that houses the LHC today. It is fed with particles by the SPS.

Four versatile detectors were installed on the LEP to observe collisions between electrons and high-energy positrons: Aleph (pictured here), Delphi, L3, and Opal.

The Antiproton Decelerator (AD) is a unique instrument, which since 2000, produces low-energy antiprotons particularly used to explore the properties of antimatter.

In the early 2000s, NA50, an experiment dedicated to the study of heavy ions, helps describe "quark-gluon plasma:" a very special state of matter that might have existed a few microseconds after the Big Bang.

Study of "quark-gluon plasma" continues today with the Alice detector. Collisions between lead ions recreate the conditions necessary for the formation of this state of matter: extreme density and temperatures.

In 2012, the LHC’s ATLAS (right) and CMS (left) experiments observe a new particle consistent with the Higgs boson, a key elementary particle in the Standard Model of particle physics.

The LHC will operate another two decades to further investigate the Higgs boson, and identify and describe unknown phenomena—known as "new physics." In the longer term, CERN plans to build a 100 km Collider, the FCC project (Future circular collider), which would make it possible to investigate an even wider range of energy.