Study of the high {gamma}{sub t} lattice for a 5-MW proton synchrotron: FODO-I

We studied the lattice suitable for a 5-MW proton source. In this study, we assumed that the 2-GeV, 1-MW proton source whose feasibility study was recently completed will be used as the injector. As a consequence, the design energy of the 5-MW source is 10 GeV. One of the primary requirements in the design of the lattice is to achieve a transition energy, {gamma}{sub t}, as high as possible in order to avoid crossing the transition and to reduce the effect of microwave instability. Even though various methods for achieving a high {gamma}{sub t} lattice exist, we chose the lattice made of FODO cells because of its simplicity and its well-known properties. Another important requirement of the lattice is the large dynamic aperture, for the emittance of beam is necessarily large in order to reduce the space-charge effects. In the FODO lattice these two requirements conflict, for the former can be achieved through the small dispersion and the large phase advance but the latter favor the opposite. We found a lattice with transition energy {gamma}{sub t} = 14.7 and dynamic aperture larger than 200 {pi} mm-mrad