A method to reduce eddy currents within iron pole plates of a 0.3 T NdFeB MRI magnet

A novel method to reduce eddy currents within the iron pole plates of a 0.3 T NdFeB MRI magnet is presented. Using an ANSYS code the effect of the eddy currents on build-up of the gradient fields is firstly investigated. Based on the simulated analysis, a couple of eddy current suppressing layers are designed to be disposed on the surfaces of the pole plates. The layers, made of ordinary low carbon steel, are slit radiately. It is demonstrated by both calculated and measured results that with the eddy current suppressing layers the gradient fields build up more rapidly.