Some technical issues for a cannelloni spallation-target at high power

Quite diverse concepts for targets have been proposed for ESS. While there is no doubt that different approaches are possible in principle, here it is argued that a large new neutron production facility, prepared for operation at an unprecedented power level, should rely as much as possible on proven technology. The neutron spallation sources SINQ and UCN at PSI feature as their standard a solid state target consisting of Zircaloy tubes filled with lead (“cannelloni”). These targets are cooled with heavy water. SINQ is currently being operated for the second decade at a power level of about 1 MW. A first quick assessment of the suitability of this target type for ESS conditions gives encouraging results but a wide variety of technical questions has still to be addressed in more detail. Possible paths for optimization as well as proposals for promising configurations are sketched.