On 18 March beam commissioning started in Linac 2, the first link in CERN’s accelerator complex. This marks the start of what will be the longest period of beam operations in the laboratory’s history, with the accelerators remaining operational throughout winter 2009/2010 to supply the LHC. This will limit the opportunities for maintenance, so teams are anticipating what they would normally have done in the winter shutdown and doing as much as possible during the consolidation work on the LHC.
The injection chain for the LHC also contains more venerable accelerators, which have had considerable refurbishment work done on them over recent years. At 50 years old this year, the PS was starting to show signs of its age back in 2003, when the long period of radiation exposure on electrical insulation caused a fault in two magnets and a busbar connection. Since then there has been a huge campaign to refurbish more than half of the PS magnets, with the 51st and final refurbished magnet being installed in the tunnel on 3 February this year. In addition, the power supplies for the auxiliary magnets have been completely replaced and this year new cables have been laid.
The Magnet Group has also thermally tested almost every part of the machine – the first thorough survey of its kind in the history of the PS. After leaving the magnets to run for several hours the team used a thermal camera to check for poor connections, which would lead to slight heating.
The SPS has also undergone considerable refurbishment on top of the normal shutdown activities over the past few years. The final 90 dipole magnets have been repaired this year, ending the three-year project to refurbish the cooling pipes in 250 of the dipole magnets. Also, most of the cabling to the short straight sections has been replaced.
