Invited Paper-Variable Energy Extraction from Negative Ion Cyclotrons

Negative hydrogen ions are accelerated at a fixed magnetic field. The energy of an extracted beam is determined by the radius of a stripping foil and its azimuth and radius determine the exit point of the beam from the cyclotron. The exit points can be adjusted so that an auxiliary magnet causes the various extracted beams to enter a common beam transport system. Since February, 1966, external beams whose energy is variable from 25 to 50 MeV have been produced by the above means at UCLA and the University of Manitoba. While this is primarily a report on the UCLA system and its performance, special features of the Manitoba system are presented.