Development and Qualification of High Current Splices and Electrical Connections for the HL-LHC Magnets

The continuity of the 18, 13, and 2 kA circuits of the HL-LHC magnets heavily relies on splices and electrical connections, to which it is worth devoting a special attention from the early phases. This spans the design of the splice or connection itself, together with the tooling and related procedure, so that the execution can reliably yield high quality results. Mindful of the history of LHC splices, robustness and reproducibility of the execution solutions are two of the fundamental parameters that have guided the technical choices made during the development phase. The number of technical solutions considered is due to the variety of possible combinations, depending on the various nature and geometry of the superconducting cables to be joined together. This wide spectrum calls for a rigorous qualification protocol, including micrography, mechanical tests before and after fatigue stress and electrical tests at room and cryogenic temperature. The article will illustrate the choices made during the development phase for the 11 selected families of splices and electrical connections, together with their qualification process, while providing results and statistics from the mechanical and electrical tests campaigns.