Optimization Method for Passive Pole Pieces Design

Abstract

The pole pieces of permanent magnet require precise design since the highly uniform magnetic field are needed for nuclear magnetic resonance imaging. A new method has been introduced in this paper to optimize the shape of passive pole pieces. Based on Filter Equation [1, 3] a field alteration function is proposed in this method to indicate the magnetic field change according to the pole pieces variation. And this function is optimized with BFGS method to determine the shape of pole pieces which produce the most uniform magnetic field. Simulation indicates that this method is much better than the optimization methods in previous published papers with respect to the speed and field uniformity.