Design of the IPHI DTL

The medium energy (about 3 to 20 MeV) part of the new generation of high power, cw proton linacs offers a wide range of choice between different type of machines (separated tank DTL, CCDTL or standard Alvarez). For the IPHI project a 5 to 10 MeV DTL following a 5 MeV RFQ has been chosen. This is a ramped-gradient machine designed to incorporate an intrinsic field ramped without the need of the post-couplers, which are used only for stabilisation purpose. The cell geometry has been optimised to house realistic quadrupole electromagnets, and then to maximise the effective shunt impedance. An error study using the multiparticle code PARTRAN allowed to choose an aperture for the drift tubes and to define the alignment tolerances of the quadrupole magnets. This paper describes the conceptual design of this DTL and its perspectives of evolution. The mechanical and QP magnet aspects of a 3-cells hot model in construction are also described.