The present disclosure relates to a cyclotron. Embodiments of the present disclosure may include an upper and lower magnet pole, an upper and lower superconducting coil arranged around each of the magnetic poles, a ring-shaped magnetic return yoke, a beam chamber between the upper and lower magnetic poles having one or more electrodes configured to accelerate ions moving substantially in the median plane, and a cryostat. The ring-shaped magnetic return yoke and the coils may form a cold mass contained within the cryostat. Further, the cryostat may not contain the upper and lower poles.