• M. Vretenar, C. Carli, R. Garoby, F. Gerigk, K. Hanke, A.M. Lombardi, S. Maury, C. Rossi
  CERN, Geneva

Linac4 is a 160 MeV, 40 mA H^- linear accelerator which will be the source of particles for all CERN proton accelerators from 2013. Its construction has started in 2008, as part of a program for the progressive replacement or upgrade of the LHC injectors during the next decade. Linac4 will initially inject into the PS Booster and at a later stage into a 4 GeV Superconducting Proton Linac (SPL), which could ultimately be upgraded to high duty cycle operation. For this reason accelerating structures, rf hardware and shielding of Linac4 are dimensioned for higher duty from the initial phase. Linac4 is normal-conducting, 80 m long and consists of an rf volume ion source, an RFQ, a beam chopping section and a cascade of three different types of 352 MHz accelerating structures. Its main design requirements are high reliability, high beam brightness and low beam loss. The accelerator will be housed in an underground tunnel on the CERN site, which can eventually be extended to the SPL, with equipment installed in a surface building above. The main parameters, the status of the main components, the planning, the project organisation and the civil engineering infrastructure are presented.

• R. Garoby, O. Brunner, S. Calatroni, E. Ciapala, F. Gerigk, A.M. Lombardi, R. Losito, V. Parma, C. Rossi, J. Tuckmantel, M. Vretenar, W. Weingarten
  CERN, Geneva

As part of the upgrade of the LHC injector complex at CERN, the construction of a 4 GeV Superconducting Proton Linac (the SPL, in fact an H^- accelerator) is planned to begin in 2012. Depending upon physics requests, it should be upgradeable to 5 GeV and multi-MW beam power at a later stage. The construction of Linac4, its low energy front end, has started at the beginning of 2008. A full project proposal with a cost estimate for the low power version of the SPL aimed at improving LHC performance has to be ready for mid-2011. As a first step towards that goal, essential machine parameters like rf frequency, cooling temperature and beam current have recently been revisited and plans have been drawn for designing and testing critical components. The SPL parameters are reviewed in the context of the CERN plans for upgrading the LHC injectors, and the foreseen developments during the next years are described.