Measurements of thermal conductivity of epoxy impregnated NbTi andNb3Sn windings

The effective thermal conductivity in the transverse direction is one of the less predictable coil parameters. In the framework of the construction of a high-field solenoid (18 T, 100 mm free bore at 4.2 K) at the LASA lab, an experimental apparatus was built for measurement of thermal conductivity of pure materials as well as of composites and coil blocks. The main aim of the experiment is the measurement of the thermal conductance of pieces of real NbTi and Nb₃Sn windings. The authors discuss how the thermal conductivity affects the quench properties of superconducting magnets. The main features of the experimental apparatus are described together with a calculation and a measurement of the thermal loss. Preliminary measurements on some pure materials as well as on a coil block are presented