Cryogenic line for LHC at CERN [ Return towards  References  ]

To achieve what amounts to world first with this cryogenic line, allowing 100 tons of liquid helium to flow over a distance of 27 km, Air Liquide implemented a two-phase programme.
In 2001, after three years in development, the group provided a prototype to supply an initial 100 meter long section. Its effectiveness was validated by CERN, and in 2002 Air Liquide was selected to design and industrialize the whole cryogenic ring.

To broaden the prototype principle to cover the five cryogenic lines vacuum fitted over the 27 km of the ring, the Air Liquide teams had to carry out new research, set new parameters, and take into account the industrialization implicit in a project of this kind. They also had to organize themselves so that they could produce all the elements that had to be delivered and assembled at CERN on 5 European sites, handle thousands of benchmarks and large quantities of each one.
When it came to actual mass production, each workshop had to be fit for purpose (sometimes even created and equipped), specialist equipment provided, operators qualified, stocks built up, sites supplied with parts and components etc.

The QRL site ran into a number of problems, for which Air Liquide found solutions.

A very extensive amount of work needed to be done. The logistics were thought out, with the help of CERN, to make it easier to exchange, move and route the equipment. The teams communicated under the tunnel by GSM and travelled around on bicycles. The huge size of the site also meant that the 2,600 component parts in the QRL had to be accurately mapped, to ensure traceability. 125,000 data items were processed.

The site is buried underground, with all the drawbacks implicit in operations in a confined atmosphere. Concerns over safety were at the heart of all operating procedures. The teams wore the Oxalair emergency masks created by Air Liquide for the aeronautics industry. Air Liquide even designed some specialized technological tools, like a welding machine head, unique in the world, which moves automatically into places the welder’s hand cannot reach.

The effectiveness of cryogenics depends on how clean the equipment is and on how tight it is. Air Liquide has developed a technique for on-site leak searches, a tricky operation in a tunnel. On 12,000 welds completed, only ten leaks were revealed.