Thermal conductance measurements of bolted copper to copper joints at sub-Kelvin temperatures Original Research Article

We have measured the thermal contact conductance of several demountable copper joints below 1 K. Joints were made by bolting together either two flat surfaces or a clamp around a rod. Surfaces were gold plated, and no intermediate materials were used. A linear dependence on temperature was seen. Most of the measured conductance values fell into a narrow range: 0.1–0.2 W K−1 at 1 K. Results in the literature for similar joints consist of predictions based on electrical resistance measurements using the Wiedemann–Franz law. There is little evidence of the validity of this law in the case of joints. Nevertheless, our results are in good agreement with the literature predictions, suggesting that such predictions are a reasonable approximation.