The LHC will use some 1248 superconducting dipole magnets to keep its proton beams on course. Generating an operating field of up to 8.33 Tesla, these are among the most technologically challenging of LHC components. An intensive prototyping exercise concluded in 2000, when an order was placed for 30 magnets each from three potential suppliers. The collared coils of these magnets have since been arriving at CERN for assembly into cold masses. The first cold masses from each supplier were assembled, welded and finished at CERN’s magnet assembly facility while the following ones were assembled and welded at CERN and then returned to the suppliers for finishing. Personnel from industry have been stationed at CERN to be trained in this task.
CERN has developed a unique automatic process for welding the two 15 m long half-cylinders of each magnet’s cold mass. This will ensure the quality, precision and uniformity required. To date, a single hydraulic press at CERN has been used. Now the technique has been perfected, however, and the laboratory has invested in three more presses, one for each of the suppliers building the magnets. The first press to become operational is at the French Alstom-Jeumont consortium, where a magnet was assembled, fully welded and finished at the end of 2001. The others began operation at Noell in Germany and Ansaldo in Italy earlier this year.
Following approval of the dipole magnet contract by CERN Council last December (CERN Courier January/February p4), the definitive production schedule is now under discussion with the supplying companies.
