High Field Cos-Theta FalconD-C Dipole Magnet Development at CERN

The FalconD (Future Accelerator post-LHC Cosθ Optimized Nb3Sn Dipole magnet is part of the High Field Magnet (HFM) CERN programme. In collaboration with the Italian Institute for Nuclear Physics (INFN Genova and LASA Milano), CERN is developing a cos θ dipole magnet beyond 12 T based on proven Nb3Sn technology in the MQXF quadrupole used in the high-luminosity upgrade of the LHC. The magnet, with design aperture diameter of 50 mm, provides a bore field of 12 T for a 73 TeV center-of-mass energy scenario for the Future FCC-hh Circular Collider. The project has specific objectives to investigate cos-θ short magnet model design based on a two-layers coil with a wide high current cable. Moreover, the study of mechanical dipole structures based on aluminum shell with bladders and key (B&K) developed for the HL-LHC MQXF quadrupole will be presented as a baseline. The structure pre-loading system assembly baseline shall be tested on sub-scale mechanical mock ups at 77 K prior to building two single aperture 1.5 m long Nb3Sn magnet models followed by a 2-in-1 dipole magnet assembly. In this paper, we provide an overview of the magnetic and structural design carried out at CERN on an increased aperture diameter variant supported by first preliminary winding trials and give insights of the project timeline. Some preliminary protection scheme assessment is presented as baseline to be tested. Following the cable winding outcomes and the mechanical properties measured, some alternative coil optimized magnetic cross-section is reported.