Measurements of decreasing tungsten thermal conductivity in an operating spallation neutron target

Temperature measurements on the new-style tantalum-clad tungsten plate target for the ISIS First Target Station (TS-1) have been analysed to provide information on changes in tungsten thermal conductivity as proton-beam-induced damage to the tungsten in the target increases. The analysis is based on high-resolution measurement of target plate temperature decay rates when the irradiating proton beam is suddenly switched off, so that the resultant thermal conductivity data are obtained directly from a proton-driven spallation neutron target whilst the target is being irradiated.