Compact Cold Iron Weak Focusing Superconducting Cyclotron Device

A compact, cold, weak-focusing superconducting cyclotron can include at least two superconducting coils on opposite sides of a median acceleration plane. A magnetic yoke surrounds the coils and contains an acceleration chamber. The magnetic yoke is in thermal contact with the superconducting coils, and the median acceleration plane extends through the acceleration chamber. A cryogenic refrigerator is thermally coupled both with the superconducting coils and with the magnetic yoke.