16 T hybrid dipole for an LHC Energy Doubler

We report the design for a hybrid block-coil dual dipole using advanced cable-in-conduit windings. The dipole is designed for use in the arcs of an energy-doubling lattice in the LHC tunnel. The block-coil design facilitates configuration of hybrid sub-windings of Bi-2212 and Nb 3 Sn, each operating to the same fraction of critical current. The cryogenics utilizes supercritical helium, operating in the window 4.3-5.5 K. A novel support structure provides robust support and stress management. The three sub-windings can be separately wound and heat-treated, then assembled and preloaded to complete the dipole. The short-sample field using commercially available Nb3Sn and Bi-2212 is 16.8 T. With a recently reported APC Nb3Sn, the short-sample field is 18.5 T.