Spallation neutron sources and high power proton accelerators

A review is presented of high power (from tens of kW to several MW) proton accelerators used in spallation neutron sources. Different combinations of accelerators are compared with regard to their different applications. Major problems concerning accelerator physics and technology are also discussed, including many at the frontiers of research. As an example, the Chinese Spallation Neutron Source project and its accelerator system are briefly described.