Improved Configuration of Halbach Magnets with a Homogeneous Magnetic Field for Portable NMR Device
Keywords:
Halbach magnet, improved configuration, particle swarm optimization, portable NMRAbstract
Halbach array magnets are widely used in portable nuclear magnetic resonance (NMR) devices that the homogeneity of the magnetic field generated by the array affects the imaging quality. In this paper, we propose some improvements to the construction of the Halbach magnets to enhance magnetic field uniformity. Using a Halbach array model comprising 16 magnets, all the calculations are based on 3D finite element method (FEM) analysis and optimized using the particle swarm optimization (PSO) algorithm. Comparisons of the results are shown to support the observations that the optimized and improved constructions can generate a more homogeneous magnetic field.
Downloads
References
D. E. Woessner, “The early days of NMR in the Southwest,” Concepts in Magnetic Resonance, vol. 13, pp. 77-102, 2001.
M. Sagawa, S. Fujimura, H. Yamamoto, Y. Matsuura, and K. Hiraga, “Permanent magnet materials based on the rare earth-iron-boron tetragonal compounds,” IEEE Transactions on Magnetics, vol. 20, pp. 1584-1589, 1984.
G. Eidmann, R. Savelsberg, P. Blümler, and B. Blümich, “The NMR MOUSE, a mobile universal surface explorer,” Journal of Magnetic Resonance, Series A, vol. 122, pp. 104-109, 1996.
K. Halbach, “Permanent magnets for production and use of high energy particle beams,” in Proceedings of the Eighth International Workshop on Rare Earth Cobalt Permanent Magnets and Their Applications, Dayton, Ohio, pp. 103, May 1985.
Z. Zhu and D. Howe, “Halbach permanent magnet machines and applications: A review,” IEE Proceedings-Electric Power Applications, vol. 148, no. 4, pp. 299-308, 2001.
W. Min, M. Zhang, Y. Zhu, B. Chen, G. Duan, J. Hu, and W. Yin, “Analysis and optimization of a new 2-D magnet array for planar motor,” IEEE Transactions on Magnetics, vol. 46, pp. 1167-1171, 2010.
E. Danieli, J. Mauler, J. Perlo, B. Blümich, and F. Casanova, “Mobile sensor for high resolution NMR spectroscopy and imaging,” Journal of Magnetic Resonance, vol. 198, pp. 80-87, 2009.
N. Doğan, R. Topkaya, H. Subaşi, Y. Yerli, and B. Rameev, “Development of Halbach magnet for portable NMR device,” Journal of Physics: Conference Series, 153. 012047, 2009.
C. W. Windt, H. Soltner, D. Dusschoten, and P. Blümler, “A portable Halbach magnet that can be opened and closed without force: The NMRCUFF,” Journal of Magnetic Resonance, vol. 208, pp. 27-33, 2011.
H. Raich and P. Blümler, “Design and construction of a dipolar Halbach array with a homogeneous field from identical bar magnets: NMR Mandhalas,” Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, vol. 23, pp. 16-25, 2004.
B. Hills, K. Wright, and D. Gillies, “A low-field, low-cost Halbach magnet array for open-access NMR,” Journal of Magnetic Resonance, vol. 175, pp. 336-339, 2005.
J. Chen and C. Xu, “An improved discrete configuration of a cylinder magnet for portable nuclear magnetic resonance instruments,” Journal of Applied Physics, vol. 101, pp. 123926-123926, 2007.
J. Kennedy and R. Eberhart, “Particle swarm optimization,” IEEE International Conference of Neural Networks, Perth, Australia, pp. 1942-1948, 1995.
M. AlRashidi and M. El-Hawary, “A survey of particle swarm optimization applications in electric power systems,” IEEE Trans. Evolutionary Computation, vol. 13, pp. 913-918, 2009.
J. Park, Y. Jeong, J. Shin, and K. Lee, “An improved particle swarm optimization for nonconvex economic dispatch problems,” IEEE Trans. Power Systems, vol. 25, pp. 156-166, 2010.
G. Moresi and R. Magin, “Miniature permanent magnet for table‐top NMR,” Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, vol. 19, pp. 35-43, 2003.
H. Soltner and P. Blümler, “Dipolar Halbach magnet stacks made from identically shaped permanent magnets for magnetic resonance,” Concepts in Magnetic Resonance Part A, vol. 36, pp. 211-222, 2010.
Y. Y. Cheng, T. Hai, Y. B. Zheng, B. L. Li, and L. Xia, “Optimization and design of multi-ring pole pieces for small-sized permanent magnetic resonance imaging magnet,” Applied Computational Electromagnetics Society Journal, vol. 33, no. 9, pp. 1026-1033, 2018.
Y. Cheng, L. Xia, W. He, M. Zhu, and F. Liu, “Improved Halbach magnets by particle swarm optimization for mobile nuclear magnetic resonance systems,” in Ninth International Conference on Natural Computation, IEEE, pp. 798-802, 2013.
S. Anferova, V. Anferov, J. Arnold, E. Talnishnikh, M. A. Voda, K. Kupferschläger, P. Blümler, C. Clauser, and B. Blümich, “Improved Halbach sensor for NMR scanning of drill cores,” Magnetic resonance imaging, vol. 25, pp. 474-480, 2007.
C. Z. Cooley, J. P. Stockmann, B. D. Armstrong, M. Sarracanie, M. H. Lev, M. S. Rosen, and L. L. Wald, “Two‐dimensional imaging in a lightweight portable MRI scanner without gradient coils,” Magnetic Resonance in Medicine, vol. 73, pp. 872- 883, 2014.