C Rossi

Conceptual design of the SPL II : A high-power superconducting

An analysis of the revised physics needs and recent progress in the technology of superconducting RF cavities have led to major changes in the specification and in the design for a Superconducting Proton Linac (SPL) at CERN. Compared with the first conceptual design report (CERN 2000–012) the beam energy is almost doubled (3.5 GeV instead of 2.2 GeV), while the length of the linac is reduced by 40% and the repetition rate is reduced to 50 Hz. The basic beam power is at a level of 4–5 MW and the approach chosen offers enough margins for upgrades. With this high beam power, the SPL can be the proton driver for an ISOL-type radioactive ion beam facility of the next generation (‘EURISOL’), and for a neutrino facility based on superbeam C beta-beam or on muon decay in a storage ring (‘neutrino factory’). The SPL can also replace the Linac2 and PS Booster in the low-energy part of the CERN proton accelerator complex, improving significantly the beam performance in terms of brightness and intensity for the benefit of all users including the LHC and its luminosity upgrade. Decommissioned LEP klystrons and RF equipment are used to provide RF power at a frequency of 352.2 MHz in the lowenergy part of the accelerator. Beyond 90 MeV, the RF frequency is doubled to take advantage of more compact normal-conducting accelerating structures up to an energy of 180 MeV. From there, state-ofthe-art, high-gradient, bulk-niobium superconducting cavities accelerate the beam up to its final energy of 3.5 GeV. The overall design approach is presented, together with the progress that has been achieved since the publication of the first conceptual design report.

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The PS Multi-Turn Extraction Study Group M. J. Barnes*, O. E. Berrig, A. Beuret, J. Borburgh, P. Bourquin, R. Brown, J.-P. Burnet, F. Caspers, J.-M. Cravero, T. Dobers, T. Fowler, S. Gilardoni, M. Giovannozzi (Study Group Leader), M. Hourican, W. Kalbreier, T. Kroyer, F. di Maio, M. Martini, V. Mertens, E. Métral, K.-D. Metzmacher, C. Rossi, J.-P. Royer, L. Sermeus, R. Steerenberg, G. Villiger, T. Zickler