High intensity H− injector linacs

An overview is given for the at NuFact ’99 as most promising identified 4 MW proton driver concepts for neutrino factories. The H− injector linac needs at least 25 mA ionsource current and more than 0.1 MW beam power at the linac end. The dominating design feature of any high intensity injector linac is to bring particle losses down to 1 W/m at the linac end and to guarantee loss-free ring injection afterwards. Halo formation of mismatched bunched beams in periodic focusing systems is discussed. RF control problems are summarized for at 100 Hz rep. rate pulsed medium β superconducting cavities either made as bulk niobium or as niobium sputtered copper cavities. The high rep. rate leads to remaining cavity wall deformation from pulse to pulse.