Conceptual design of the SPL, a high-power superconducting H$^-$ linac at CERN

The conceptual design of a superconducting H -linear accelerator at CERN for a beam energy of 2.2 GeV and a power of 4 MW is presented.Using most of the superconducting RF cavities available after the decommissioning of LEP, it operates at 352 MHz and delivers 10 16 protons per second, in 2.2 ms bursts with a repetition rate of 75 Hz.In conjunction with an accumulator and a compressor, it is designed to be the proton driver of a neutrino factory at CERN.At an early stage, it will upgrade the performance of the PS complex by replacing Linac2 and the PS Booster, by injecting protons directly into the PS.The brilliance of the LHC beam will thus be tripled.The present ISOLDE facility can be supplied with five times more beam current than today, and a new-generation radioactive ion beam facility receiving up to 100 A beam current could also be accommodated.More generally, the PS beam intensity will be substantially increased at all energies, with a direct benefit for fixedtarget physics and especially neutrino physics based on pion decay.