LHC restart pushed back, may not run at 14 TeV

Physics Today : The Large Hadron Collider is on schedule to restart in the fall, but running three weeks late, says CERN Director General Rolf Heuer .The delay will push back the restart of the project until October. A bad breakThe LHC has been offline since an incident on 19 September, caused by a faulty splice in the high-current superconducting cable between two superconducting magnets in sector 3-4.There are more than 10,000 similar splices in the LHC, all of which are currently being checked for flaws.The incident caused CERN to develop some noninvasive techniques to check for bad joints in the system while the collider is cooled down below 80 kelvin.More than 39 dipole and 14 quadrupole magnets were taken to the surface for repairs.Heuer told the CERN council last week that these tests indicate there could be another faulty splice in Sector 4-5.CERN has also modified and conducted a major upgrade of the magnets’ safety system to limit the damage another break could cause if a similar incident happens again. 14 TeV?Meanwhile, the LHC may not run at full capacity for sometime. The existing repairs will allow the device to run at a collision energy of 8 TeV, but further modifications will be required to run at 10 TeV collision energy or higher. According to reports of a talk given by Jörg Wenninger —who is from CERN Beams department’s operation group—there are problems with quenching the magnets from one of the three firms that supplied CERN. This new quality control issue could mean that the LHC may not be able to go above 10 TeV collisions. Related Link Status of the LHC Machine