Cable-in-conduit dipoles to enable a future hadron collider

We report the development of a new approach to dipole technology, based upon cable-in-conduit conductor, that optimizes the cost and performance for a future ultimate-energy hadron collider. Optimization of cost for an ultimate-energy hadron collider is dominated by the strong dependence of magnet cost and synchrotron radiation power upon the dipole field strength. Assuming that the collider is built at a site with minimum tunnel cost, the projected total project cost is minimum for a ∼4 T dipole field. We present a novel option in which the double-ring of magnets is housed in a circular pipeline, submerged with neutral buoyancy at a depth ∼100 m in the sea. Such a collider inscribed in the Gulf of Mexico would provide hadron collisions at 500-TeV energy with a luminosity of 5 × 10³⁵ cm^-2s^-1. We describe here the design of the dipole and of the pipeline cryostat that would contain it.