• F. Gerigk, S. Atieh, S. Calatroni, O. Capatina, E. Ciapala, M. Eshraqi, L.M.A. Ferreira, R. Garoby, M. Hernandez Flano, W. Höfle, E. Lebbos, A.M. Lombardi, E. Montesinos, Th. Otto, V. Parma, P.A. Posocco, T. Renaglia, M. Schuh, V. Vlachoudis, W. Weingarten, S. Weisz
  CERN, Geneva
• R. Calaga
  BNL, Upton, Long Island, New York

During the past 2 years the Superconducting Proton Linac (SPL) study has grown into an international collaboration with the goal of optimising the architecture of a pulsed superconducting (SC) high-power proton linac. This effort includes the study and prototyping of major technical components, such as SC high-gradient cavities, power couplers, the RF distribution system, HOM couplers, cryo-modules, focusing elements, etc. Even though the effort is driven by CERN specific needs, the established design principles are valid for a range of superconducting linac projects. In this paper we report on the latests decisions concerning the machine architecture and on the ongoing R&D effort for technical components.

• O. Brunner, E. Ciapala, J.N. Schwerg
  CERN, Geneva

Linac4 is a linear accelerator for negative Hydrogen ions (H-) which will replace the old Linac2 as linear injector for the CERN accelerators. Its higher energy of 160 MeV will give increased beam intensity in the downstream machines. Linac4 is about 100 m long, normal-conducting, and will be housed in a tunnel about 12 m below ground. The Linac4 tunnel will be connected to the existing chain of accelerators and can be extended to the new injection chain. The high RF power for the Linac4 accelerating structures will be generated by thirteen 1.3 MW klystrons, previously used for the CERN LEP accelerator, and six new 2.8 MW klystrons of all operating at a frequency of 352.2 MHz. The integration of the RF power system in the building is presented. The technical specifications and the performance of the various high-power elements are discussed, with emphasis on the required retuning of the LEP klystrons. The power distribution system including the power splitting requirements are also described.