High-power proton linacs are envisaged as drivers for numerous applications, as neutron spallation source for condensed matter study, neutrino factories and muons colliders, hybrid systems for transmutation or energy production, production of rare isotope beams for nuclear physics studies, etc. These new linear accelerators are intended to deliver proton beam of up to several MW and even to several tens of MW power and operate with CW or pulsed high intensity beams. There is a general trend for adopting the superconducting technology, which offers some advantages, like higher gradient capabilities or operational costs reduction, as compared to room-temperatures accelerating structures. The primary concern of building such high-power linacs is the minimisation of beam losses, which could limit their availability and maintainability due to excessive activation of the machine and irradiation of the environment. A careful beam dynamics design is therefore needed to avoid the formation of particle halo that would finally be lost in the linac or in transfer lines. Furthermore, some applications, like accelerator driven systems (ADS) require a very low number of beam interruptions, which could affect the lifetime of key components such as windows, reactor parts and structure, as well as the ADS operation. This paper gives a survey of typical high-power accelerators projects under construction or in planning, compares the beam and linac parameters and points out the choice of the technical options and of the components.
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