The fabrication of superconducting magnet for MRI

Abstract The fabrication and the test results of the superconducting magnet for a whole body MRI are presented. The magnet consists of a main coil with six solenoids, a shielding coil with two solenoids, and six sets of cryogenic shim coil. The ferromagnetic shim assembly is installed on the inside wall of the room temperature bore to compensate the inhomogeneous field components that originated in insufficient tolerances, installation misalignments, and external ferromagnetic materials near the magnet. In addition, the magnet is enclosed by a horizontal type cryostat with the room temperature bore of 80 cm. According to the test of the MRI magnet, the central field of the magnet is 1.5 T with a field homogeneity of 9.3 ppm on 40 cm DSV (the diameter of spherical volume). Some magnetic resonance images for human body have been achieved by employing this magnet.