CERN: LHC completes the circle. ‘At a brief ceremony deep under the French countryside today, CERN Director General Robert Aymar sealed the last interconnect between the main magnet systems in the Large Hadron Collider (LHC). This is the latest milestone in commissioning the LHC, the world’s most powerful particle accelerator.
The LHC’s superconducting main magnets will operate at a temperature of just 1.9 degrees above absolute zero (-271.3 oC), colder than outer space. To cool the magnets, over 10 000 tonnes of liquid nitrogen and 130 tonnes of liquid helium will be deployed through a cryogenic system including more than 40 000 leak-tight welds. Today’s ceremony marks the end of a two year programme of work to connect all the main dipole and quadrupole magnets in the LHC. This complex task included both electrical and fluid connections.
“This is a huge accomplishment,” said Lyn Evans, LHC project leader. “Now that it is done, we can concentrate on getting the machine cold and ready for physics.”
The LHC is a circular machine, 27 kilometres around and divided into eight sectors, each of which can be cooled down to its operating temperature of 1.9 degrees above absolute zero and powered-up individually. One sector was cooled down, powered and warmed up in the first half of 2007. This was an important learning process, allowing subsequent sectors to be tested more quickly.’