Calculation Method of the Shielding Factor for Large-Scale Zero Magnetic Field Facility
Sun Zhiyin1, Li Liyi1, Pan Donghua1, Liu Tianhao2, Peter Ferlinger3
1. Laboratory for Space Environment and Physical Sciences Harbin Institute of TechnologyHarbin 150001 China;
2. School of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150001 China;
3. Department of Physics Technische Universität München München D-85748 Germany
For the facility to realize the nearly zero magnetic field, the shielding factor is hard to predicted accurately because of imperfect factors including edges, holes and airgaps, etc. A large-scale facility is composed of permalloy sheets with widths of a few meters and thicknesses of a few millimeters, and hence brings a challenge to meshing in finite element method (FEM) model. In this paper, the improved FEM methods are presented for shields in both DC field and AC field, using two types of interior boundaries to calculate the field changes because of the shield. It is demonstrated by the comparison with theoretical analysis of ideal shields. On the base of the improved FEM methods, the multilayer shield can be optimized efficiently and the influences of holes on the shielding factor can be analyzed. The presented calculation methods are applied to the new built magnetic shielded room (MSR) in technische universität München (TUM) and verified by the shielding factors measurement.
孙芝茵, 李立毅, 潘东华, 刘添豪, PeterFerlinger. 大型零磁装置屏蔽系数的计算方法[J]. 电工技术学报, 2018, 33(19): 4450-4457.
Sun Zhiyin, Li Liyi, Pan Donghua, Liu Tianhao, Peter Ferlinger. Calculation Method of the Shielding Factor for Large-Scale Zero Magnetic Field Facility. Transactions of China Electrotechnical Society, 2018, 33(19): 4450-4457.
[1] 李立毅, 孙芝茵, 潘东华, 等. 近零磁环境装置现状综述[J]. 电工技术学报, 2015, 30(15): 136-140.Li Liyi, Sun Zhiyin, Pan Donghua, et al. Status reviews for nearly zero magnetic field environment facility[J]. Transactions of China Electrotechnical Society, 2015, 30(15): 136-140.
[2] Altarev I, Babcock E, Beck D, et al.A magnetically shielded room with ultra low residual field and gradient[J]. Review of Scientific Instruments, 2014, 85(7): 075106.
[3] Altarev I, Babcock E, Beck D, et al.A large-scale magnetic shield with 106 damping at millihertz frequencies[J]. Journal of Applied Physics, 2015, 117(18): 183903.
[4] Matsushima M, Tsunakawa H, Iijima Y, et al.Magnetic cleanliness program under control of electromagnetic compatibility for the SELENE (Kaguya) spacecraft[J]. Space Science Reviews, 2010, 154(1-4): 253-264.
[5] Burghoff M, Sander T H, Schnabe A, et al.DC magnetoencephalography: direct measurement in a magnetically extremely-well shielded room[J]. Applied Physics Letters, 2004, 85(25): 6278-6280.
[6] Hwang S M, Körber R, Kim K, et al.Superconductors in SQUID-based ultralow field NMR-flux-trapping in type-II wires[J]. IEEE Transactions on Applied Superconductivity, 2015, 25(3): 1-4.
[7] Bork J, Hahlbohm H D, Klein R, et al.The 8-layered magnetically shielded room of the PTB: design and construction[C]//Proceedings of 12th International Conference on Biomagnetism, Espoo, Finland, 2001: 970-973.
[8] Kajiwara G, Harakawa K, Ogata H, et al.High-performance magnetically shielded room[J]. IEEE Transactions on Magnetics, 1996, 32(4): 2582-2585.
[9] Harakawa K, Kajiwara G, Kazami K, et al.Evaluation of a high-performance magnetically shielded room for biomagnetic measurement[J]. IEEE Transactions on Magnetics, 1996, 32(6): 5256-5260.
[10] Baum E, Bork J.Systematic design of magnetic shields[J]. Journal of Magnetism and Magnetic Materials, 1991, 101(1-3): 69-74.
[11] Rikitake T.Magnetic and electromagnetic shielding [M]. Tokyo: Terra Scientific Publishing Company, 1987.
[12] Yamazaki K, Kato K, Fujiwara K.Effective combination of magnetic and conductive layers of magnetically shielded room [for biomagnetic measurements][J]. IEEE Transactions on Magnetics, 2000, 36(5): 3649-3651.
[13] Thiel F, Schnabel A, Knappe-Gruneberg S, et al.Demagnetization of magnetically shielded rooms[J]. Review of Scientific Instruments, 2007, 78(3): 035106.
[14] Sun Z, Reisner M, Fierlinger P, et al.Dynamic modeling of the behavior of permalloy for magnetic shielding[J]. Journal of Applied Physics, 2016, 119(19): 193902.
[15] Altarev I, Fierlinger P, Lins T, et al.Minimizing magnetic fields for precision experiments[J]. Journal of Applied Physics, 2015, 117(23): 233903.
[16] Li Liyi, Sun Zhiyin, Donghua P, et al.An approach to analyzing magnetically shielded room comprising discontinuous layers considering permeability in low magnetic field[J]. IEEE Transactions on Magnetics, 2014, 50(11): 1-4.
2018, Vol. 33 
