The dipoles reach the half-way mark

With the positioning of the 616th magnet, installation of the LHC dipoles has reached the half-way mark.

Only half the dipoles remain to be installed! The 616th dipole out of a total of 1232 was installed at 3 a.m on Wednesday 12 July. Night and day, the tunnel is the setting for a never-ending series of carefully choreographed installation operations. At a rate of around twenty per week, there has been a steady underground flow of dipole magnets, each measuring 15 metres in length and weighing 34 tonnes. 'In order to recover the accumulated delays, installation is proceeding three times faster than planned', confides Claude Hauviller, who is supervising LHC installation. Four dipoles can be transported underground at the same time. It is a real challenge, which the 65-man team responsible for this difficult task faces on a daily basis. This is because there is very little space in the tunnel and there are no passing places for the magnet transport vehicles. The room for manoeuvre can sometimes be measured in centimetres and the transport operations have to be co-ordinated with the other work being performed. Once they have been lowered down the PM12 shaft, the dipoles begin their slow progress at the pace of a walking child. They can take up to ten hours to reach Point 6, the furthest point of the ring, where they still have to be aligned and interconnected. Other work is being performed in parallel. Over the summer the installation of Sector 7-8 of the LHC, consisting of the very first continuous chain of magnets and cryostats and their cryogenic distribution line, will be completed. Octant 7-8 will be cooled down and tested before the end of the year.

Did you know?

The whole of the LHC comprises around 9300 magnets, assembled in 1746 units. The most numerous are the dipoles, of which there are 1232. In the tunnel, six specially adapted vehicles are used to transport these very fragile components, at a speed of 3 km/h. At the end of their journey, the magnets are placed on a transfer table in order to be installed in their final position.