LCLS-II LINAC 2.0 K Commissioning

Abstract In 2023, SLAC commissioned a continuous-wave superconducting linear accelerator (CW SCRF Linac) to support its new Linac Coherent Light Source (LCLS-II). The LCLS-II Linac comprises 37 cryomodules, each equipped with superconducting niobium cavities. These cryomodules hold helium bath operating at 2.0 K for the electron beam. Achieving the 2.0 K temperature in the Linac involves reducing the liquid helium saturation pressure to 31 mbar using a series of centrifugal compressors. This paper presents the results of the commissioning of the 2K system at SLAC.