The European Spallation Source, ESS, will use a super- conducting linear accelerator delivering high current long pulses with an average beam power of 5 MW to the target station at 2.5 GeV. A new cryomodule architecture is pro- posed that can have a quasi-segmented interlacing which provides enough room for beam diagnostics, and can reduce the cryo heat load with respect to the segmented de- sign by keeping the transition regions at sub-100 K region.
This paper will present a review of the linac design, beam dynamics studies and a preliminary cryogenic analysis of the transition region.