The Cryogenic System for the LHC Test String 2: Design, Commissioning and Operation

A 107-m long superconducting magnet string representing a full-cell of the LHC machine was designed for assembly and commissioning at CERN in order to validate the final design choices. This new facility, thereafter called Test String 2, and its cryogenic infrastructure cons ist of feed and return boxes coupled via transfer lines to a 6 kW @ 4.5 K refrigerator and to a low pressure pumping group, a separate cryogenic distribution line, an electrical feed box with HTS current leads, 2 quadrupole and 6 dipole prototype and pre-series superconducting magnets.