Exchanging LHC magnets at CERN

Several of the LHC's 1232 dipoles will be replaced over the course of the second long shutdown of CERN's accelerator complex. Major endeavours have got under way way in the Large Hadron Collider (LHC) over the past few weeks, with the extraction of magnets from the accelerator tunnel. The LHC has a total of 1232 dipoles, magnets which bend the particles’ trajectories, and 474 quadrupoles, which squeeze the bunches. All these magnets are superconducting, i.e. they operate at a temperature of –271°C, are 15 metres long and weigh up to 28 tonnes. So moving them around is no trivial matter. During the second long shutdown, 22 of these large components (including 19 dipoles) have to be replaced, especially as several have been showing operating deficiencies. Twelve have already been brought above ground and the last one is scheduled to be dismantled at the beginning of July.