Wobbler Facility for Biomedical Experimenis at the Bevalac

A new wobbler facility has been developed to deliver large uniform fields of relativistic heavy ions at the Bevalac without resorting to the use of scattering material in the beam. The charged particle beams are made to wobble and ´paint´ a ring at the target by a pair of dipole magnets, which are placed tandem with their fields orthogonal to each other. The magnets are powered sinusoidally 90 degrees out of phase with each other. By superimposing several rings of appropriate sizes and intensities, large uniform fields are produced. Up to 30 cm diameter fields with less than 5% variation in uniformity have been achieved. Physics and biology measurements have been made to characterize the radiation field.