Abstract: A superconducting magnet for use in a particle accelerator of the synchotron type is disclosed. The disclosed magnet includes twin bores, each having beam pipes therein. A flux pipe is provided between the twin bores such that a 360.degree. magnetic flux path is formed. A superconducting coil encircles the bores and flux pipe, for generating the transverse magnetic field across the beam pipes. The flux pipe may be formed of non-magnetic material for a linear magnet, or alternatively may be formed of ferromagnetic laminations parallel to the direction of the magnetic field to form a superferric magnet with minimal eddy current generation. The flux pipe includes magnetic stress relief bubbles near the bores, compensating for the crowding effect near the inner radius of the flux pipe.