Design of the thermal and magnetic shielding for the LHC High Luminosity Crab-Cavity upgrade

Before the High Luminosity (Hi-Lumi) upgrade of the Large Hadron Collider (LHC), two pairs of superconducting compact Crab Cavities are to be tested within separate cryomodules, on the Super Proton Synchrotron (SPS) at CERN in 2018 prior to Long Shutdown 2. Two novel side-loaded cryomodules, which allow ease of access for assembly, inspection and maintenance, have been developed for the prototype tests. The cryomodule shielding includes a thermal shield and double layer magnetic shield, consisting of a warm-outer shield, and two cold-inner shields (one per cavity). Various constraints and considerations have led to unique cold shielding, mounted inside the cavity helium vessels, resulting in several design challenges. The shielding adopts and utilises the module’s side-loaded configuration, for continuity and accessibility, while satisfying tight spatial constraints and requirements to meet the functional specification. This paper outlines the design, analysis, manufacture and assembly of the Hi-Lumi SPS test cryomodule’s thermal and magnetic shielding, which are critical to achieving the operational stability.