A high current superconducting proton linac for an accelerator driven transmutation system

High current CW proton linac accelerators have been recently proposed for a number of applications based on the use of a large flux of spallation neutrons. In this context, an R&D program on an accelerator driven system for nuclear waste transmutation has been recently approved in Italy. Our specific task is to develop, together with the national industry, a design of the high energy part of the proton accelerator, along with prototype development for the most critical components. In this paper we present a revised version of the design proposed at Linac'96, using five cell cavities, rather than the original four cells. This modification, together with a new criterion for using the transit time factor curve for non resonant proton velocities, results in a more modular and efficient design. A 1.6 GeV linac, operated at 25 mA, allows to reach 40 MW beam power. The beam power upgrade is achievable using additional couplers per cavity.