Magnet for an 800-MeV Separated Orbit Cyclotron

The Separated Orbit Cyclotron consists of individual sector magnets and rf cavities placed alternately in a circular arrangement. The beam is bent and focused by alternating gradient fields produced by pole tips with a minimum radial spacing of 4. 5 inches. Magnet design and construction problems are minimized by using the same pole-surface contour and the same mean-field intensity throughout the entire machine. All pole tips in one sector are mounted on a common yoke and driven by a common pair of coils. Shimming gaps are provided between the yoke and the pole tips so that the same mean field intensity can be achieved for all orbits. Only the azimuthal length of the poles is changed to maintain the correct focusing and bending properties of the magnets.