Lattice Design Studies for the CERN Proton Driver Accumulator and Compressor

The CERN baseline scenario for a Neutrino Factory comprises accumulation and compression of the beam delivered by a 2.2 GeV kinetic H- linac, to provide the time structure needed on the target. Originally, accumulation and bunch compression in one single ring was envisaged. To limit the RF voltage necessary for bunch rotation, quasi-isochronous lattices were studied. The low transition energy together with the long circumference, either leads to large dispersion or necessitates the addition of bending magnents with negative deflection angle. Several solutions for quasi-isochronous lattices were investigated. Finally, the quasi-isochronous lattices were abandoned, and a solution has been chosen with two seperate rings, one for accumulation and the other for bunch-compression, and conventional lattices working far below transition.