Compensated Precessional Beam Extraction Apparatus for Synchrocyclotrons

A plurality of magnetic extraction bumps are incorporated into a cyclotron that further includes (a) a pair of magnetic coils encircling a central axis and positioned on opposite sides of a median acceleration plane and (b) a magnetic yoke encircling the central axis and including a return yoke that crosses the median acceleration plane and a first and second pole on opposite sides of the median acceleration plane. The magnetic extraction bumps extend in series radially from the central axis on opposite sides of the median acceleration plane and can be used to extract an orbiting accelerated ion from the cyclotron.