LHC magnets: the great descent

A first dipole magnet was delivered to its final location in the LHC tunnel on Monday, 7 March. This achievement coincides with another important milestone in the installation of the future collider, the completion of the delivery of half the dipole magnets.

On 7 March at 2.00 p.m., the first 35-tonne dipole magnet was lowered down through the PMI2 shaft, reaching the floor of the TI2 transfer tunnel thirty minutes later.

At 2.00 p.m. on Monday, 7 March, the teams from the TS-IC (Installation Coordination) group lowered the first of the 1232 superconducting dipole magnets into the LHC tunnel. By 11.00 p.m. the 15-m-long magnet weighing 35 tonnes was positioned in its final location in the tunnel between Point 8 and Point 1.

This achievement marks the start of installation of the very heart of the machine. In addition to these main dipole magnets, hundreds of other, smaller magnets are to be installed. The TS-IC group will have to lower a total of some 1800 magnet assemblies into the tunnel ready for precise positioning and connection.

These vital components will all take the same route. The magnets are lowered into the tunnel via the PMI2 shaft, a specially made shaft of oval cross-section located at the western end of the Meyrin site. Fifty metres below, they "touch down" in the TI2 transfer tunnel, where they begin their underground journey through the LHC tunnel on specially designed vehicles (see Bulletin No. 14/2003). At a speed of 3 km/hour this journey can take several hours. "The narrowness of the tunnel makes these handling operations quite difficult", explains Claude Hauviller, Head of the TS-IC group, which is in charge of LHC installation. "It will be impossible for two loads to pass each other and there are often only a few millimetres to spare." Once they reach their final destination, the magnets are unloaded onto a transfer table for precise positioning.

All this is nothing new for the teams, which have been in training for some time. At the beginning of the year, for example, a string of three dipoles and a quadrupole was put together for testing in the tunnel, not far from Point 2.

The magnet was transported to its final location between Points 8 and 1 by a specially designed vehicle.

It was then positioned with great precision and unloaded using a transfer table.

Delivery of the dipole magnets reaches the half-way mark

The lowering of this first magnet into the tunnel coincides with another milestone for CERN, namely completion of the delivery of half the superconducting dipole magnets. By 7 March, a total of 616 magnets had been delivered. This is a remarkable achievement bearing in mind the difficulties involved in the move from the prototyping and pre-series phase to large-scale series production. Lucio Rossi, Head of the AT-MAS group, which is in charge of the production of the main magnets, celebrated this achievement with his team at a small get-together on Tuesday, 8 March.

"We will need to keep up our hard work. We are on track to complete production by autumn 2006", Lucio Rossi explains. The three companies responsible for assembling the magnets - Babcock Noell Nuclear in Germany, Alstom in France and Ansaldo in Italy - are now able to manufacture between nine and ten magnets a week.

The teams in charge of the LHC magnets with the panel testifying to the delivery of the 616th magnet. In the first row, seated, from left to right: C. Bosteels, AT-MAS group secretary, R. Aymar, Director-General, L. Rossi, Head of the AT-MAS group, L. Evans, LHC Project Leader, P. Lebrun, Head of the AT Department, W. Scandale , Deputy Head of the AT-MAS group and J.-P. Koutchouk, Head of the AT-MAS Analysis Section.