波谱学杂志2026，Vol.43Issue(3)：253-267,15.DOI:10.11938/cjmr20263205
大口径高均匀度核磁共振Halbach磁体研究
Research on Large-bore and High Homogeneity Halbach Magnet for Nuclear Magnetic Resonance
摘要
Abstract
Halbach permanent magnets hold significant promise for low-field nuclear magnetic resonance(LF-NMR)applications,such as rock core analysis,owing to their yoke-free design and low external stray fields.Compared with small rock cores,large rock cores better preserve the original internal structure and fluid distribution,yet they demand a larger homogeneous region.However,the complex structure of Halbach magnets inherently yields inadequate initial homogeneity,making it difficult to directly obtain a sufficiently large homogeneous region.In this study,we defined a 100-mm-diameter spherical region of interest(ROI)and optimized the magnet structure using Halbach magnet theory and finite-element simulations.The final designed magnet provides a field strength of 158.4 mT and an initial homogeneity of 22 502 ppm(1 ppm=10-6).We applied an improved harmonic-based passive shimming method and enhanced the field homogeneity to 1 496 ppm.After passive shimming,we acquired 1H free induction decay(FID)signals from an aqueous CuSO4 sample(Φ 100 mm×H 100 mm),and Carr-Purcell-Meiboom-Gill(CPMG)signals from a two-component CuSO4 aqueous solution,and distinguished different samples based on their T2.These results demonstrate that the proposed magnet design and passive shimming method are effective for constructing large-bore,high homogeneity Halbach magnets.关键词
核磁共振/Halbach磁体/磁体设计/无源匀场/磁场均匀度Key words
NMR/Halbach magnet/magnet design/passive shimming/magnetic field homogeneity分类
数理科学引用本文复制引用
刘万震,陈方,陈黎,王佳鑫,程鑫,易鹏,张志,刘朝阳..大口径高均匀度核磁共振Halbach磁体研究[J].波谱学杂志,2026,43(3):253-267,15.基金项目
国家自然科学基金(22574167,22374158,22404165,22127801,22327901) （22574167,22374158,22404165,22127801,22327901）
国家重点研发计划(2022YFF0707000,2023YFE0113300) （2022YFF0707000,2023YFE0113300）
中国科学院基础与交叉前沿科研先导专项(XDB0540300). （XDB0540300）
