  The use of superconductivity is well-known as a method to increase the
average field of a cyclotron and thereby to allow a substantial reduction of
its size and mass. We present a compact high-field design for the first
superconducting cyclotron with rare-earth (holmium) poles. Our design supports
stable acceleration of protons to Ek = 70 MeV with no significant limit in beam
current, suitable for wide applications in ocular therapy, isotope production,
radiobiological studies and nuclear physics.
