Large Hadron Collider Takes a Break for Winter Maintenance

When accelerators are asleep, technical teams went to work. Since December 14 there were circulating particles anywhere in the CERN accelerator chain, from the source of particles of intermediate rings and the Large Hadron Collider (LHC) itself. Technical stop end of the year is the opportunity to do maintenance work on the computer and repair the damage and to upgrade the machines for the next races.

"We started planning this technical stop as early as June 2015," said Marzia Bernardini, the team leader who organizes and coordinates the work. "Hundreds of people of all technical services have participated in 12 weeks".

A long list of maintenance work had to be completed with significant improvements on all machines and infrastructure. In Proton Synchrotron (PS), for example, the third link of the chain, is installed two new beam instrumentation equipment.

Another cycle long, 16 magnets 1818 in the Super Proton Synchrotron (SPS) and transfer lines were replaced LHC. Since each magnet weighing 16 tons, which is a big job, but it is done regularly. The SPS will be 40 this year and magnets wear out over time and need to be renovated.

In the LHC, several major operations are underway. Two injection beam absorbers have been replaced. These huge six meters long pieces of equipment are used when the rays are expelled from the SPS and the LHC: MSF absorb the beam if a problem occurs, providing vital protection for the LHC.

Accelerator complex cryogenic system is regular maintenance. Two of the eight sectors of the LHC have been emptied helium coolant to ensure that no data is lost while it is being repaired one of the refrigerators. Twelve collimators, on both sides of ATLAS and CMS, were dismantled ready to be updated.

These devices protect the machine in which absorbent particles away from the beam path. Finally, wiring campaigns continue through the machine: four teams working in parallel to install 25 kilometers of signal cables of new equipment and improvements.

The work not only affects the accelerators, but also experiences, in particular, the LHC experiments. Collaborations are most of the judgment for maintenance and upgrades in their detectors, which are composed of millions of components.

Work on the injectors must be completed in early February and the LHC and its experiments in early March. The injectors are then gradually restarted while the LHC magnets are tested before the arrival of the first beams at the LHC scheduled for late March.