The Directorate of CERN confirmed today the schedule for restarting the Large Hadron Collider (LHC), following the recommendations of the workshop held in Chamonix last week. The new calendar provides for first beams in the LHC at the end of September this year, and collisions in late October. A short stop technique has also been planned during the holiday season. The LHC will operate without interruption until then the fall of 2010, enabling experiments to have sufficient data to perform the first analysis for the new physics and have results to announce in 2010. The new schedule also provides for the possibility of collisions of lead ions in 2010.
In Chamonix, a consensus was reached among all the technical experts to recognize that the new schedule is tight, but realistic.
"The schedule we have now is undoubtedly the best for the LHC and physicists who are waiting for data," said Rolf Heuer, Director General of CERN. It is a prudent timetable, which aims to carry out the works necessary before restarting the machine, but which nevertheless start operating for physics this year. "
This new schedule represents a delay of six weeks compared to the previous projection for a set LHC cold early July. This delay is explained by several factors, including the establishment of a new system of enhanced protection for the connections of busbars and magnets, installing new valves to reduce secondary damage in case of incidents, implementing security measures and constraints related to timing of transfer and storage of helium.
The system of protection measures the electrical resistance in the cables and connections are much more sensitive than the system in place on 19 September.
The new system of protection against overpressure was created in two phases. The first phase is to install valves on the pumping stations on existing vacuum the whole ring. Calculations showed that with this initial protection, incident similar to the September 19, the secondary damage would be limited. The second phase is to add valves on all dipoles, the measure to ensure that the secondary damage (for interconnections and superisolation) would be limited even in the worst case scenarios over the entire lifetime of the LHC.
Management has decided, for 2009, install the valves on four of the eight sectors of the LHC, parallel repairs damaged in the area last September and other building work already undertaken. The dipoles of the four remaining sectors will be equipped in 2010.
