Progress in the Elliptical Cavities and Cryomodule Demonstrators for the ESS LINAC

The European Spallation Source (ESS) accelerator is a large superconducting linac under construction in Lund, Sweden. A collaboration between CEA Saclay, IPN Orsay and ESS-AB is established to design the elliptical cavities cryomodule of the linac. It is foreseen to build and test two cryomodule demonstrators within the next two years. We present the design evolution and the fabrication status of the cryomodule components housing four cavities. The latest test results of two prototype cavities are shown. The cryomodule assembly process and the ongoing testing infrastructures at CEA Saclay are also described.