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CERN – LHC

On a quest to understand the birth of the universe

CERN, the European Organization for Nuclear Research, is one of the largest and most prestigious science laboratories in the world. The work done by its researchers in seeking to reveal the fundamental laws of the universe and the ultimate constituents of matter has many applications in daily life, particularly in medicine and computing.

The most advanced instrument used by CERN is the Large Hadron Collider (LHC), a particle accelerator for which Air Liquide has designed a unique complex cryogenic distribution system.

The machine that turns back time

Commissioned in 2008, the LHC (Large Hadron Collider) is the world's largest and most powerful particle accelerator. Inside the accelerator, two high-energy particle beams travel at close to the speed of light in opposite directions in separate beam pipes kept at ultrahigh vacuum. They are then made to collide in a 27-kilometre ring 100 meters underground to recreate the conditions that prevailed in the first moments of the universe. 

The magnets must be chilled to -271°C, a temperature colder than outer space itself.

Analysis of these collisions and the thousands of particles they create provides a better understanding about how the universe was born. In 2012, the LHC made it possible to demonstrate the existence of the Higgs Boson, an elementary particle essential to the Standard Model of particle physics used to describe the components with which the universe is constructed.

Particles are guided around the accelerator ring by superconducting electromagnets whose magnetic fields are 100,000 times greater than that the Earth's own magnetic field. This level of power is needed to keep the two particle beams 'on the rails' and ensure that they collide. The magnets must be chilled to -271°C, a temperature colder than outer space itself.

The multi-faceted challenge to distribute liquid helium

As a CERN partner since 1975, Air Liquide has achieved a world first as part of the LHC construction project: designing and producing the world's largest cryogenic system capable of distributing 100 metric tons of liquid helium around the 27-kilometer ring.

Air Liquide has achieved a world first as part of the LHC construction project.

The LHC is directly connected to the Air Liquide-designed liquid helium distribution system essential to chill the 1,700 superconducting electromagnets to their optimum operating temperature of -271°C.

Air Liquide has achieved a world first as part of the LHC construction project: designing and producing the world's largest cryogenic system capable of distributing 100 metric tons of liquid helium around the 27-kilometer ring.

Achieving this world first required us to overcome three major technological challenges:

  • Chilling 1,700 electromagnets around a 27-kilometer ring to 1.9K (-271°C), a temperature only 1.9 degrees above absolute zero. Absolute zero is the lowest temperature possible (0K on the Kelvin scale or -273.15°C on the Celsius scale)
  • Design, manufacture and assembly of the 3,000+ components used to create the cryogenic system in its entirety
  • Manufacturing (to 1/10th of a millimeter accuracy) of the 300 connection points between the cryogenic system and the LHC magnets, with an assembly tolerance of between 0.2% and 1% in all three dimensions

The exceptional size of this cryogenic system makes it one of the largest technological challenges yet achieved by the Group.