IRON-FREE PERMANENT-MAGNET SYSTEMS FOR CHARGED-PARTICLE BEAM OPTICS

The strength and astounding simplicity of certain permanent magnet mat erials allow a wide variety of simple, compact configurations of high field strength and quality multipole magnets. Here we analyze the impo rtant class of iron-free permanent magnet systems for charged particle beam optics. The theory of conventional segmented multipole magnets f ormed from uniformly magnetized block magnets placed in regular arrays about a circular magnet aperture is reviewed. Practical multipole con figurations resulting are presented that are capable of high and inter mediate aperture field strengths. A new class of elliptical aperture m agnets is presented within a model with continuously varying magnetiza tion angle. Segmented versions of these magnets promise practical high field dipole and quadrupole magnets with an increased range of applic ability.