ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS |
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Shim coil design for Halbach magnet by equivalent magnetic dipole method |
Jia-Min Wu(吴嘉敏)1, Zheng Xu(徐征)1, Pan Guo(郭盼)2, Jin-Feng Qi(戚金凤)1, Yu-Cheng He(贺玉成)1 |
1 State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044, China;
2 School of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331, China |
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Abstract Low-field nuclear magnetic resonance magnet (2 MHz) is required for rock core analysis. However, due to its low field strength, it is hard to achieve a high uniform B0 field only by using the passive shimming. Therefore, active shimming is necessarily used to further improve uniformity for Halbach magnet. In this work, an equivalent magnetic dipole method is presented for designing shim coils. The minimization of the coil power dissipation is considered as an optimal object to minimize coil heating effect, and the deviation from the target field is selected as a penalty function term. The lsqnonlin optimization toolbox of MATLAB is used to solve the optimization problem. Eight shim coils are obtained in accordance with the contour of the stream function. We simulate each shim coil by ANSYS Maxwell software to verify the validity of the designed coils. Measurement results of the field distribution of these coils are consistent with those of the target fields. The uniformity of the B0 field is improved from 114.2 ppm to 26.9 ppm after using these shim coils.
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Received: 18 May 2018
Revised: 12 June 2018
Accepted manuscript online:
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PACS:
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41.20.Gz
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(Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems)
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02.60.Pn
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(Numerical optimization)
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Fund: Project supported by the State Key Development Program for Basic Research of China (Grant No. 2014CB541602), the National Natural Science Foundation of China (Grant Nos. 51677008 and 51707028), and the Fundamental Research Funds of Central Universities, China (Grant No. 106112015CDJXY150003). |
Corresponding Authors:
Zheng Xu, Pan Guo
E-mail: xuzheng@cqu.edu.cn;guopan@cqnu.edu.cn
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Cite this article:
Jia-Min Wu(吴嘉敏), Zheng Xu(徐征), Pan Guo(郭盼), Jin-Feng Qi(戚金凤), Yu-Cheng He(贺玉成) Shim coil design for Halbach magnet by equivalent magnetic dipole method 2018 Chin. Phys. B 27 104101
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[1] |
Windt C W, Soltner H, Van D, D and Blümler P 2011 J. Magn. Reson. 208 27
|
[2] |
Danieli E, Perlo J, Blümich B and Casanova F 2010 Ange. Chem. 49 4133
|
[3] |
Cooley C Z, Haskell M W, Cauley S F, Sappo C, Lapierre C D, Ha C G, Stockmann J P and Wald L L 2018 IEEE Trans. Magn. 54 5100112
|
[4] |
Tayler M C D and Sakellariou D 2017 J. Magn. Reson. 277 143
|
[5] |
Turner R 1993 Magn. Reson. Imag. 11 903
|
[6] |
Lu H, Jesmanowicz A, Li S J and Hyde J S 2004 Magn. Reson. Med. 51 158
|
[7] |
Villa M, Savini A and Mustarell P 1989 Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, November 9-12, 1989, Seattle, WA USA, p. 605
|
[8] |
Crozier S and Moddrell D M 1995 Magn. Reson. Imag. 13 615
|
[9] |
Crozier S and Moddrell D M 1993 J. Magn. Reson. 103 354
|
[10] |
Adamiak K and Czaja A J 1994 IEEE Trans. Magn. 30 4311
|
[11] |
Sanchez H, Liu F, Trakic A, Weber E and Crozier S 2007 IEEE Trans. Magn. 43 3558
|
[12] |
Garrett M W 1951 J. Appl. Phys. 22 1091
|
[13] |
Compton R A U S Patent 4456881 1984-06-26
|
[14] |
Wong E, Jesmanowicz A and Hyde J S 1991 Magn. Reson. Med. 21 39
|
[15] |
Schenck J F, Hussain M A and Edelstein W A U S Pantent 4646024 1987-02-24
|
[16] |
Brideson M A, Forbes L K and Crozier S 2002 Con. Magn. Reson. 14 9
|
[17] |
Turner R 1986 J. Phys. D:Appl. Phys. 19 L147
|
[18] |
Liu W T, Zu D L and Tang X 2010 Chin. Phys. B 19 018701
|
[19] |
Xu Y, Chen Q, Zhang G, Pei Z and Yang X 2015 Appl. Magn. Reson. 46 823
|
[20] |
Lopez H S, Liu F, Poole M and Crozier S 2009 IEEE Trans. Magn. 45 767
|
[21] |
Liu W T, Casanova F and Blumich B 2012 Appl. Magn. Reson. 42 101
|
[22] |
Chu X, Jiang X H and Jiang J G 2005 Pro. CSEE 25 139 (in Chinese)
|
[23] |
Xu Z, Li X, Guo P and Wu J M 2018 Chin. Phys. B 27 058702
|
[24] |
Zhao W, Tang X Y and Liu Z W 2010 Trans. Chin. Elec. Soci. 25 6 (in Chinese)
|
[25] |
Anderson W A 1961 Rev. Sci. Instr. 32 241
|
[26] |
Brideson M A, Forbes L K and Crozier S 2002 Con. Magn. Reson. 14 9
|
[27] |
Feng C Z 1985 Static electromagnetics (Xi'an:Xi'an Jiaotong University Press) (in Chinese)
|
[28] |
While P T, Forbes L K and Crozier S 2011 IEEE Trans. Bio. Eng. 58 2418
|
[29] |
While P T, Korvink J G, Shah N J and Poole M S 2013 J. Magn. Reson. 235 85
|
[30] |
Nocedal J, Wright S J 1999 Numerical Optimization, 2nd edn., p. 419
|
[31] |
Chen S S, Xia T, Bi X, Miao Z Y, Yang P Q, Wang H Z and Dai S G 2017 Chin. J. Magn. Reson. 34 87
|
[32] |
Diehl P, Fluck E and Kosfeld R 1972 NMR Basic Principles Progress/Grundlagen und Fortschr, Vol. 7 (Berlin, Heidelberg:Springer-Verlag) p. 56
|
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