A look at the damage that halted the LHC

On Friday, the European Centre for Nuclear Research (Cern) released photos of damage to the Large Hadron Collider (LHC), Cern's flagship particle accelerator. The particle accelerator was damaged by a liquid helium leak in September, nine days into an experiment to test fundamental theories of physics by colliding beams of protons inside a 27km ring.

This picture shows two of the most severely broken interconnects, which are between the magnets in LHC sectors three and four. The superconducting magnets, used to direct and focus the proton beams in the experiment, are cooled by liquid helium. An electrical fault caused the liquid helium to leak, resulting in a need for repairs that has put the experiment out of action until at least summer 2009.

This picture shows damage to the support of one of the quadrupole magnets in sectors three to four. The LHC uses quadrupole magnets to focus opposing proton beams, and dipole magnets to keep the beams on their respective paths.

This picture shows the site of the electrical fault that caused the helium leak. A resistive zone developed in one of the electrical connections, creating an electrical arc that punctured one of the helium enclosures around a magnet, according to an analysis by Cern. The warming helium expanded in the vacuum enclosure of the central sub-sector of the pipe, damaging the vacuum barriers separating the central sub-sector from the neighbouring sub-sectors.