Division of accelerators, cryogenics and magnetism

The High Luminosity LHC (HL-LHC) project at CERN has offered the opportunity to promote and develop various types of enabling accelerator technologies, such as MgB2 superconducting links for cold powering and Nb3Sn accelerators magnets for the interaction regions.  The superconducting link is in an advanced prototyping phase and is expected to be fully validated in the coming months.  The Nb3Sn magnet development has encountered serious difficulties characterized by performance limitation or degradation which have now been overcome.  We report on the status and challenges of HL-LHC magnets and devices at CERN, with a primary focus on the root cause analysis and recovery actions implemented for the final focusing Nb3Sn quadrupole magnets, and a comparison with similar issues encountered over a decade ago on the Nb3Sn Cable-in-Conduit conductors for ITER magnets.  We also present two ongoing spin-off projects which benefit from HL-LHC technology developments: a strongly curved, Nb-Ti, canted cosine theta (CCT) magnet and an energy-efficient, MgB2, superferric dipole magnet.