News: 3 September 2009
Final LHC sector starts cool down
After the mechanical intervention carried out during last week in Sector 6-7, the cool down of this sector was restarted yesterday afternoon. This is the last sector to be cooled down, and marks a major milestone in the shutdown activities performed this year.
The cool down of Sector 6-7 had already begun two weeks ago, but the detection of a short-circuit on the main dipole circuit caused the cool down process to be stopped. The cause of the short-circuit was later identified as the weak insulation of a magnet busbar, which had been degraded by friction against a screw because of the mechanical contraction during the cool down. Mechanics prevents this from happening at low temperature. After the repair and the electrical and vacuum validation, the sector was released for cool-down.
The cool down of Sector 3-4, the one affected by September 19 incident, also started few days ago, marking the end of a complex phase of repair.
