Preliminary Conductor Layouts for the Detector Magnets of the Future Circular Collider

For the Future Circular Collider (FCC) presently under the conceptual design at the European Council for Nuclear Research (CERN), very large conductors are needed for the detector magnets. The requested critical current is an order of magnitude higher than that of the previous generation, corresponding to about 250 kA at 4.2 K and 5 T. Characteristic conductor layouts, particularly the type and fraction of structural materials, are reviewed in order to extrapolate to the most promising designs and adapt those to the requirements imposed for the FCC detector magnets. The nominal currents required at characteristic operating conditions of 6.5 T and 4.6 K, conductor dimensions, production unit lengths and mass are investigated for defining the design of the conductor. For comparing various conductor layout options, and as a first step in the conductor R&D;, it is proposed to study the conductor sizing according to relevant material characteristics.