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Niobium-tin (Nb3Sn) is the workhorse of the FCC magnet development programme. The first breakthrough results of this effort came in 2015, when a Nb3Sn magnet in Racetrack Model Coil (RMC) configuration reached a field of 16.2 T (CERN Courier November 2015 p8). The next goal is to create an enhanced RMC (ERMC) reaching a mid-plane field of 16 T with a 10% margin at a temperature of 4.2 K. The first ERMC coil was successfully wound at CERN in April this year (figure 2, left picture) and a demonstrator unit will be available by the end of the summer. The high-field magnets of the proposed FCC-hh collider would require 7000–9000 tonnes of Nb3Sn superconducting wire, with major implications for the superconductivity industry, while boosting the applications of this technology in domains outside high-energy physics.

The FCC conductor development programme aims, over an initial four-year period, to meet the challenging requirements of the FCC high-field magnets. The first results are very promising: within only one year, the Nb3Sn superconducting wires produced by various international partners have achieved the same performance as the HL-LHC wire (figure 3), and there are strong indicators that it will be feasible to meet the even more ambitious wire targets (in terms of performance and cost) for FCC. The FCC magnet development programme will require six tonnes of superconducting wire over the next five years for the construction of R&D and model magnets, representing a substantial opportunity for wire manufacturers in Europe and beyond. CERN has also launched a Marie-Curie training network called EASITrain to advance our knowledge on superconducting materials and take into account large-scale industrialisation (CERN Courier September 2017 p31).