• E.N. Zaplatin, R. Maier, M. Pap, R. Stassen, R. Tölle
  FZJ, Jülich
• W. Behr, H. Glueckler, W. Guenther, J. Wolters
  Forschungszentrum Jülich GmbH, Institut fur Nuklearchemie (INC), Jülich

The paper describes the design, fabrication and first test results of the triple-spoke cavity (resonant frequency 352 MHz, beta=0.48) developed at Forschungszentrum Jülich in the frame of High Intensity Pulsed Proton Injector project. The cavity has 5 cm diameter beam aperture, a transverse radius of 21.7 cm and the whole length of 78 cm. An initial wall thickness of niobium sheets used for cavity fabrication was around 4 mm. The RF cavity design has been adapted to two main goals - the simplest technology of cavity manufacture and for the prime goal of the project to achieve the best possible structural parameters (Lorenz force frequency shift and a resonant frequency pressure dependence). Intense cavity structural analyses have been conducted and the further prospectives on cavity developments are also presented. Construction of the niobium cavity prototype has been completed, the cavity has been chemically processed. Results of initial cold test are discussed.

• 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 deutron accelerators. A superconducting option for the 5 to 40 MeV linac is based on Half-Wave Resonators (HWR) has been choosen. The first cryomudule should contain 8 HWR's with resonant frequency of 175 MHz and beta=v/c=0.094. The paper describes RF design of half-wave length resonator. The requirents on high power coupler define its installation in the cavity central region. Few options of cavity tune were investigated, the capacitive tuner installed opposite to the coupler port have been accepted. The cavity structural analyses have been conducted and cavity stiffening has been worked out.