Design of the Superconducting Main Magnet Based on Variable Density Method in Cylindrical MRI Scanner

The magnetic resonance imaging (MRI) scanner is an important diagnosis tool. Benefiting from the development of superconductivity technology, the performance of superconducting magnet is continuously improved. Excellent homogeneity is one of the most important criteria in selecting a main magnet, which is the critical component and directly determines the imaging quality, further affecting the diagnosis of the patients. In this paper, imitating the variable density method (VDM), one of the topology optimization methods originated from mechanics, a 3.0 T cylindrical superconducting magnet for whole-body imaging was designed. In addition, two optimization models called 0-1 and -1-0-1VDM were proposed to cover different conditions. For a commercial application, 0-1VDM has the advantages in modeling and simple structure. In the aspects of the superconducting wire volume, electromagnetic stress performance and design flexibility, the -1-0-1VDM outperforms the 0-1VDM. On the other hand, the -1-0-1VDM shows great potential for designing specific magnet with an arbitrary coil arrangement area.