The cooling systems were designed and manufactured by Linde Kryotechnik AG, a Swiss company. For their work in the design of the cooling systems, CERN presented Linde with a Gold Hadron award in 2003. Representatives from Linde and two other corporations are responsible for the operation of the cooling systems.
These cooling systems make use of two different super-cooled liquids: liquid helium and liquid nitrogen. A total of 130 tons of liquid helium and 10,000 tons of liquid nitrogen are used in the system, which must be completely leak-free to operate. A leak in any one of the 40,000 welds in the system can cause serious damage and a months-long shutdown.
In order to guide the tiny particle beams, extremely powerful magnets must be used. Each magnet has a field of 8.36 Tesla (typical electromagnets can't exceed 2 Tesla). The magnets are 14 meters long and have an inner diameter of 56 millimeters.
In order to achieve the extreme field strength required of them, the magnets make use of advanced technologies: they are made of a niobium-titanium alloy and encased in copper. This is not an altogether new technology, having been invented in the 1960s, but it is being operated at much colder temperatures than in the past. These super-cold temperatures and high field strength limit the materials that can be used. While operating, the magnetic cables need to be able to carry 15,000 amps at 1.5 Kelvin while resisting many hundreds of tons of force in each meter of the cable.
To maintain the 1.9 K operating temperature, the LHC draws on a 150 kW refrigeration capacity at 4.5 K (20 kW at 1.9 K). This refrigeration capacity is obtained by use of heat exchangers around the magnets. The heat exchangers use liquid helium, which is one thousand times more heat conducting than copper, as a working fluid. The heat exchanger contains a mix of liquid and vapor helium; the vapor is taken to a header, where it is compressed down to atmospheric pressure.