Low Energy Part of the CONCERT High-Power Proton Linac

The 1.3 GeV linac of the CONCERT multi-users facility has to accelerate protons and H/sup -/ ions in a series of current pulses distributed over each 20 ms period. The peak current is identical for all pulses to keep the space charge forces about constant apart from a slight emittance change between H/sup +/ and H/sup -/ bunches. The beam power required for a given application is then obtained by adjusting the pulse duration with a total maximum power of 20 MW and 5 MW for the proton and H/sup -/ beams respectively. The reference design of the low-energy part of this linac is made-up of two separate proton and H/sup i/njectors up to 23 MeV, the H/sup -/ one using a funnelling system. These injectors are followed by a series of copper cavities up to the transition with superconducting cavities at about 185 MeV. The overall architecture, the technical choices and the beam dynamics in this high-power proton linac front end are presented and discussed.