Geneva, Switzerland – The long-awaited restart of the Large Hadron Collider (LHC) has been postponed until the winter of 2009. CERN attributed the delay to a number of technical difficulties, including vacuum leaks in two sectors of the LHC that had been cooled down to 80 K.
The leaks were reportedly discovered in sectors 8-1 and 2-3 while they were being prepared for the electrical tests on the copper stabilizers.
“Unfortunately, the repair necessitates a partial warm-up of both sectors. This involves the end sub-sector being warmed to room temperature, while the adjacent sub-sector ‘floats’ in temperature and the remainder of the sector is kept at 80 K,” CERN explained in an official bulletin.
“As the leak is from the helium circuit to the insulating vacuum, the repair work will have no impact on the vacuum in the beam pipe. However the intervention will have an impact on the schedule for the restart. It is now foreseen that the LHC will be closed and ready for beam injection by mid-November.”
Nevertheless, all planned repairs have been completed in Sector 4-5 and the final ‘W bellow’ – the large accordion-shaped sleeve that covers the interconnections between two magnets – was closed on Wednesday 15 July.
“The foreseen shutdown work on the LHC is proceeding well, including the powering tests with the new quench protection system,” added CERN.