Thermal resistance between metallic surfaces in different configurations for high current HTS Cable-in-Conduit Conductor

High Temperature Superconductors (HTS) are promising candidates for high current Cable-In-Conduit Conductors (CICC) for large high-field magnets. In many cases, these CICCs are made from several HTS strands, which themselves consist of individual HTS tapes. Quench propagation in CICCs is currently under intensive investigation, and it can be predicted by modelling the entire cable structure. To model the heat transfer, along with material properties the thermal properties of contact interfaces between structural materials are highly needed. There are different kinds of thermal contacts in CICC: contacts between superconducting tapes stacked together, contacts between thin copper of stainless steel tapes, and between bulks of structural materials. This work focuses on characterizing the thermal contact resistance between metallic surfaces in various configurations relevant to high-current HTS CICC systems. Experiments were conducted across a range of pressures (50 N to 200 N) and temperatures (6 K to 300 K) to assess the thermal contact resistance behavior. The analysis included both soldered, unsoldered HTS tapes and the BRAST braid. For soldered tapes, surface treatments using citric acid were applied to reduce the presence of surface oxides, while unsoldered stacks and BRAST braid were evaluated under different pressure conditions to determine the impact on contact area and heat transfer. The results of this study provide a comprehensive overview of thermal contact resistance behavior under varying operational conditions, contributing valuable insights into the design and thermal management of superconducting cables for fusion reactors and other high-current applications.