Water Cooled Targets for Intense Ion Beams

Target backings cooled by water in linear flow have proven capable of dissipating heat loads from 2 kW ion beams focused to about 20 mm2 for extended periods without structural failure. In addition to the more obvious modes of failure by plastic deformation and melting, metallographic studies of damaged targets have revealed deep void penetrations along grain boundaries. The targetry limitations imposed on maximum usable beam power by heat transfer from the backing to the cooling fluid have been investigated. Neutron producing lifetimes of LiF targets have been compared for different proton beam and coolant flow conditions.