一种新型的铁屏蔽式短腔MR超导磁体设计方法

A design method for a novel iron shielded MR superconducting magnet

目的针对一种新型的直接将铁屏作为杜瓦室温屏的铁屏蔽式MR超导磁体,提出一种新的设计优化方法。方法根据设计指标使用参数加权法构建目标函数,然后利用模拟退火算法(SAA)优化该目标函数,得到全局最优解,并采用有限元法对铁屏蔽超导磁体产生的电磁场进行计算。结果该方法模拟设计了一种全身MR系统短腔1.5T铁屏蔽式超导磁体,腔长1.6m,400mm球成像区域,磁场峰峰值2.2ppm,5Gs线7.1m(轴向)×5.3m(径向)。结论该优化方法对设计铁屏蔽式短腔MR超导磁体非常有效。

Objective To design an optimization method for a novel iron shielded MR superconducting magnet used iron shield as the warm wall of the Dewar. Methods Weighting method based on the design target was used to construct objective function which was optimized in simulated annealing algorithm （SAA）. The finite element method （FEM） was adopted in the method to calculate the magnetic field produced by the iron shielded superconducting magnet. Results A compact 1.5T iron shielded superconducting magnet for the whole body MR imaging was designed with the presented method. The length of the magnet was 1.6 m, the magnetic field homogeneity （peak to peak relative deviation） in the sphere of 400 mm diameter at the isocenter of the magnet was 2.2 ppm, the 5 Gs line was 7.1 m in axial direction and 5.3 m in radial direction. Conclusion The method for designing compact iron shielded superconducting magnet of MR imaging is valid.