摘要：Superconducting magnet system for a 28GHz ECR ion source has been *** maximum axial magnetic fields are 4T at the rf injection side and 2T at the beam extraction side,*** hexapole magnetic field is about 2T on the inner surface of the plasma *** superconducting coils consist of six solenoids and six racetrack windings for a hexapole *** kinds of coil arrangements were investigated:one is an arrangement in which the hexpole coil is located in the bore of the solenoids,and another is the reverse of *** coils use NbTi-Copper conductor and are bath-cooled in liquid *** six solenoids are excited with individual power supplies to search for the optimal axial field *** current leads use high Tc material and the cryogenic system is operated in LHe re-condensation mode using small *** thermal insulated supports of the cold mass have also been designed based on the calculated results of the magnetic *** heat loads to 70K and LHe stages were estimated from the design of the supports,the current leads and so on.