Base Line Design for a Beta/Beam Neutrino Facility

The term beta-beam has been coined for the production of pure beams of electron neutrinos or their antiparticles through the decay of radioactive ions circulating in a storage ring. The neutrino source itself consists of a high-energy storage ring (gamma ~150), with long straight sections in line with the experiment(s). The radioactive ions (6He and 18Ne) will be produced in an ISOL type target system. Due to the short life times of around 1 s at rest, the beam needs to be accelerated as quickly as possible. For this a staged system of accelerators is proposed. The chain starts with a linac followed by a rapid cycling synchrotron for acceleration up to ~300 MeV/u. For further acceleration the existing PS and SPS machines are used. Finally, after acceleration to SPS top energy, the ions are transferred to a decay ring where they are merged with the existing bunches through a longitudinal stacking procedure. The baseline design of the beta-beam facility will be presented together with its major problems. Potential solutions to the latter will be discussed.