An Optimal Design of Actively Shielded MRI Superconducting Magnet

An optimal design method of magnetic resonance imaging (MRI) magnet from specifications of field uniformity and stray field is presented. Linear programming with objective of volume of superconductors is first taken to get currents in array of coils. Then, nonzero current regions are converted to actual coils with rectangular cross section. Next, nonlinear optimization with objective of deviation of magnetic field in diameter of spherical volume is taken to adjust positions of converted coils. An example of actively shielded MRI superconducting magnet is used to show effectiveness of the optimization method.