Thermal performance analysis and measurements of the prototype cryomodules of European XFEL accelerator—Part II

Three accelerator prototype cryomodules (CMs) for the European XFEL have been produced, assembled and tested at DESY in a wide international collaboration. The heat load budget is a key element in the qualification of these CMs. We describe in this paper the measurements performed in the Cryomodule test bench (CMTB) to evaluate the thermal performances of the three prototype CMs. We present at first the methodology and instrumentation used for the measurements, then we analyse the main contributions to the heat loads at various temperature levels and finally we compare the measured values with the ones calculated and reported in the first part of this paper.