Design considerations for a large aperture high field superconducting dipole

The final phase of the Fermilab upgrade proposal calls for a new ring of superconducting magnets to be placed in the existing main accelerator tunnel. The goal of this design study is to specify a high field dipole (HFD) that is capable of supporting fixed target operation (ramping, resonant extraction) at a field of 6.6 T (1.5 TeV) and colliding beam physics at 8.0 T (1.8 TeV). The magnetic field quality at high field is set by the large amplitude orbits associated with resonant extraction. The fixed quality must therefore be at least as good as the existing Tevatron magnets which fulfil these criteria. The high fields and large aperture of this magnet result in large forces on the coil and collar assemblies. Therefore, the cold mass design must be able to sustain these forces while providing sufficient cooling to the coils during 4.2-K fixed target operation, and a minimum heat load during 1.8-K collider operation