The 4.5 K refrigerators in the LHC cryogenics system: refrigeration schemes and commissioning status

by U. Wagner (CERN-AT)

Thursday 4 Sept 2003, 14:15 → 15:15 Europe/Zurich

AT Auditorium (CERN)

As part of the cryogenic system for the LHC machine four new refrigerators delivering capacity at 4.5 K have been purchased in 1998 from two suppliers. Three of these refrigerators have passed the Provisional Acceptance Test (PAC) the fourth refrigerator is still under commissioning. The presentation recalls first the refrigeration scheme of the LHC machine and details the process design chosen by the suppliers in order to cope with the specified requirements. Then the fabrication, installation and commissioning progress of the refrigerators is discussed and the schedule is compared with what has been foreseen in the Technical Specification. Finally the performance of the three refrigerators that are already accepted is reported.