• E.N. Zaplatin
  FZJ, Jülich
• P. Bosland, P. Bredy, N. Grouas, P. Hardy, J. Migne, A. Mosnier, F. Orsini, J. Plouin
  CEA, Gif-sur-Yvette

The driver of the International Fusion Material Irradiation Facility (IFMIF) consists of two 125 mA, 40 MeV cw deuteron accelerators [1-2]. A superconducting option for the 5 to 40 MeV linac based on Half-Wave Resonators (HWR) has been chosen. The first cryomodule houses 8 The driver of the International Fusion Material Irradiation Facility (IFMIF) consists of two 125 mA, 40 MeV cw deuteron accelerators. A superconducting option for the 5 to 40 MeV linac based on Half-Wave Resonators (HWR) has been chosen. The first cryomodule houses 8 HWR's with resonant frequency of 175 MHz and geometric beta=v/c=0.094. This paper describes the RF design of half-wave length resonator together with structural analyses. Detailed simulations of resonance multipactor discharge in HWR are presented. Due to the required high coupling, the power coupler is located in mid-plane of the cavity. Several cavity tuning options were investigated: the capacitive tuner located in mid-plane and opposite to the power coupler port offers a large tuning range and will be tested first.