DEVELOPMENT OF HIGH POWER TARGETS

High power targets are at the very heart of most applications of accelerators to science and technology. With many projects aiming to utilize beams in the multi-megawatt power range, solid targets, in particular stationary ones, become increasingly difficult to cool. Liquid metal targets are often the concept of choice. Designs range from fully enclosed systems for neutron generation to free jets to allow extraction of low energy highly ionizing radiation (pions and muons). Mercury is often the preferred target material due to its liquid state at room temperature and other favourable properties. For designs aiming at high temperature operation or depending on small neutron absorption PbBi is the preferred target material. Liquid lithium is proposed for a deuteron stripping target for the IFMIF project. Issues to be solved include solid-liquid metal reactions, radiation effects, general liquid metal technology, handling of spallation products as well as design of components and subsystems. In addition, short pulse operation leads to the generation of pressure waves inside the targets and to the need to control their consequences