Target Cooling Options for Neutron Sources at High Power Densities

Compact neutron sources in many cases beat large ones when it comes to power density; thus, many issues concerning cooling are shared, and each party can learn a lot from the other facilities. Starting from accrued experience with water cooling at moderate power densities in SINQ over the last 15 years, a brief overview will be attempted showing the relevant parameters and specific approaches at several existing and planned neutron (spallation) sources. Extensions from the established ground of cooling with water will be sketched in two directions. An outline of an experiment planned for freshly determining in a representative geometry the hard limit for water cooling, i.e. full boiling, will be given, and possibilities for pushing the borders by replacing the coolant will be indicated. In particular, experience with LBE in Megapie as well as a potentially promising outlook for the use of gallium are shortly discussed.