AUTOMATIC TRIMMING TECHNIQUE FOR MULTIPOLAR MAGNETS

The paper presents a technique for identifying and removing unwanted terms in the field power expansion of multipolar magnets. The technique is based on the measurement of the radial field at the poles of the magnet. The field terms are derived by analytical formulas and used to evaluate the current corrections. This trimming procedure has been tested for a 16-pole magnet designed for electron paramagnetic resonance imaging and permits a continuous control of the field configuration.