As the final countdown begins towards the scheduled start-up of the Large Hadron Collider at CERN later this year, work on the machine and the experiments has seen a series of achievements during the closing weeks of 2006. The cool-down of the first complete sector – an eighth of the machine – has already begun and installation of the magnets should be completed in March.
At the end of October, the final sector of the cryogenic distribution line, sector 1-2, passed pressure and helium leak tests at room temperature, “completing the circle” for at least one major component of the LHC. The line will circulate helium in liquid and gas phases, at different temperatures and pressures, to provide the cryogenic conditions for the superconducting magnets. The test marked the end of a key part of the project that has had to overcome major difficulties, including manufacturing faults.
Then on 10 November the first complete sector – sector 7-8 – became operational, with the magnets, cryogenic line, the vacuum chambers and the distribution feedboxes all fully interconnected. The interconnection work had required several thousand electrical, cryogenic and insulating connections to be made on the 210 interfaces between the magnets in the arc, the 30 interfaces between the special magnets and the interfaces with the cryogenic line. Although representing only an eighth of the LHC, the fully equipped sector from points 7 to 8 will be the world’s largest operating cryogenic system.
Production of the LHC’s main magnets has finally finished, with a celebration at CERN on 27 November. In all 1232 main dipole and 392 main quadrupole magnets have been manufactured in an unprecedented collaboration effort between CERN and European industry.
The LHC experiments are also continuing to make good progress. On 8 November, the giant ATLAS barrel toroid magnet reached its nominal field of 4 T, with a current of 21 kA in the superconducting coils. At the same time, the first sections of the CMS detector had begun to arrive in the experimental cavern, 100 m below ground. The first forward hadronic (HF) calorimeter, weighing 250 tonnes, led the way on 2 November, with the second HF following a week later. The first end-cap disc, the 410 tonne YE+3, made its 10 h descent on 30 November, followed by YE+2 on 12 December. The third end-cap disc, YE+1, weighing in at nearly 1300 tonnes, was the heaviest piece so far to be lowered, taking 11 h on 9 January.
These milestones were a major feature of a confident report on the LHC to CERN Council at its 140th meeting on 15 December. The meeting also saw the election of Torsten Åkesson of the University Lund as president of Council from 1 January 2007, taking over from Enzo Iarocci. On the same date, Sigurd Lettow replaced Andre Naudi as CERN’s chief financial officer.
