Chun-zhong WANG(王春忠)1,2, Qiu-liang WANG(王秋良)1, Lan-k ai LI(李兰凯)1,Ming RONG(荣明)2, You-yuan ZHOU(周又元)3
1. Institute of Electrical Engineering, Chinese Academy of Scienc es, Beijing 100864, China;2. Academy of Armored Forces Engineering, Beijing 100072, China;3. Yichang Testing Technique Research Institute, Yichang 443003, China
Abstract-The optimal design method for an open Magnetic Resona nce Imaging (MRI) superconducting magnet with an active shielding configuration is proposed. Firstly, three pairs of current rings are employed as seed coils. B y optimizing the homogeneity of Diameter Sphere Volume (DSV), the positions and currents of the seed coils will be obtained. Secondly, according to the position s and currents of the seed coils, the current density of superconducting wires i s determined, and then the original sections for the coils can be achieved. An o ptimization for the homogeneity based on the constrained nonlinear optimization method is employed to determine the coils with good homogeneity. Thirdly, the ma gnetic field generated by previous coils is set as the background field, then ad d two coils with reverse current, and optimize the stray field line of 5 Gauss i n a certain scope. Finally, a further optimization for the homogeneity is used t o get final coils. This method can also be used in the design of other axisymmet ric superconducting MRI magnets.
Key words-MRI; superconducting magnet; nonlinear least square optimization
Manuscript Number: 1674-8042(2010)02-0178-05
dio: 10.3969/j.issn.1674-8042.2010.02.19
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