V H − LINAC FOR CERN HIGH-INTENSITY A C h s n p t c c w w b f 4 t 3 f d d s

bstract The SPL (Superconducting Proton Linac) study at ERN foresees the construction of a 2.2 GeV linac as a igh beam-power driver for applications such as a econd-generation radioactive ion beam facility or a eutrino superbeam. At the same time such a high-erformance injector would both modernize and improve he LHC injection chain. The 120 MeV normal-conducting section of the SPL ould be used directly in a preliminary stage for H− harge-exchange injection into the PS Booster. This ould increase the proton flux to the CERN experiments hile also improving the quality and reliability of the eams for the LHC. The 120 MeV linac consists of a ront-end, a conventional Drift Tube Linac (DTL) to 0 MeV and a Cell Coupled Drift Tube Linac (CCDTL) o the full energy. All the RF structures will operate at 52 MHz, using klystrons and RF equipment recovered rom the LEP collider. This paper concentrates on the esign of the 3 to 120 MeV section. It introduces the esign criteria for high-stability beam optics and the RF tructure design work for the relatively low-frequency CDTL. The advantages of this structure with respect to ther solutions are outlined. The results of measurements n a cold CCDTL model are presented. 1 HIGH-INTENSITY AT CERN- THE SPL Increasing demand for higher performance of the roton beams has triggered a series of studies in the last ew years that are still supported in spite of the recent ecision to focus the quasi-totality of CERN resources on he LHC project. Considering only the currently approved hysics programme plus the LHC experiments, a lack of rotons can be foreseen from the LHC start-up. oreover, the CERN neutrino and radioactive ion ommunities have ambitious plans that would address ew fundamental physics and open the way for a vivid esearch programme at CERN between the LHC and a uture linear collider but would introduce additional emands on the proton production complex. An improved njector complex would not only provide the new beams ut also enhance the beam brightness, paving the way for n LHC upgrade. Until now, the main emphasis has been on the design o