Progress in Superconductivity and Cryogenics (한국초전도ㆍ저온공학회논문지)

The Korean Society of Superconductivity and Cryogenics (한국초전도저온학회)
권호 표지
DOI QR코드

DOI QR Code

Design of ferromagnetic shims for an HTS NMR magnet using sequential search method

  • Received : 2021.12.08
  • Accepted : 2021.12.23
  • Published : 2021.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

This study deals with the ferromagnetic shims design based on the spherical harmonic coefficient reduction method. The design method using the sequential search method is an intuitive method and has the advantage of quickly reaching the optimal result. The study was conducted for a 400 MHz all-REBCO magnet, which had difficulty in shimming due to the problem of SCF (screening current induced field). The initial field homogeneity of the magnet was measured to be 233.76 ppm at 20 mm DSV (Diameter Spherical Volume). In order to improve the field homogeneity of the magnet, the ferromagnetic shim with a thickness of 1 mil to 11 mil was constructed by a design method in which sequential search algorithm was applied. As a result, the field homogeneity of the magnet could be significantly improved to 0.24 ppm at 20 mm DSV and 0.05 ppm at 10 mm DSV.

Keywords

Acknowledgement

This works was supported by both the Korea Medical Device Development Fund grant funded by the Korea government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, the Ministry of Food and Drug Safety) (Project Number: 1711138068, KMDF_PR_20200901_0063) and KBSI grant C140210. It is partially supported by Institute of Engineering Research of KSNU.

References

  1. D. C. Larbalestier, J. Jiang, U. P. Trociewitz, F. Kametani, C. Scheuerlein, M. Dalban-Canassy, M. Matras, P. Chen, N. C. Craig, P. J. Lee, E. E. Hellstrom, "Isotropic round-wire multifilament cuprate superconductor for generation of magnetic fields abobe 30 T," Nature materials, vol.13, no. 4, pp. 375-381, Mar 2014. https://doi.org/10.1038/nmat3887
  2. Y. Yanagisawa, R. Piao, S. Iguchi, H. Nakagome, T. Takao, K. Kominato, M. Hamada, S. Matsumoto, H. Suematsu, X. Jin, M. Takahashi, T. Yamazaki, H. Maed, "Operation of a 400 MHz NMR magnet using a (RE:Rare Earth)Ba2Cu3O7-x high-temperature superconducting coil: Towards an ultra-compact super-high field NMR spectrometer operated beyond 1 GHz," J. Magn. Reson. vol.249, pp.38-48, Dec. 2014. https://doi.org/10.1016/j.jmr.2014.10.006
  3. Seung-yong Hahn, Juan Bascunan, Woo-Seok Kim, Emanuel S. Bobrov, Haigun Lee, and Yukikazu Iwasa, "Field Mapping, NMR Lineshape, and Screening Currents Induced Field Analyses for Homogeneity Improvement in LTS/HTS NMR Magnets," IEEE Trans. on Appl. Superconduct., vol.18, no.2, pp.856-859, Jun. 2008. https://doi.org/10.1109/TASC.2008.921225
  4. Min Cheol Ahn, Tsuyoshi Yagai, Seungyong Hahn, Ryuya Ando, Juan Bascunan, and Yukikazu Iwasa, "Spatial and Temporal Variations of a Screening Current Induced Magnetic Field in a Double-Pancake HTS Insert of an LTS/HTS NMR magnet," IEEE Trans. Appl. Supercond., vol.19, no.3, pp.2269-2272, Jun. 2008. https://doi.org/10.1109/TASC.2009.2018102
  5. Seungyong Hahn, Min Cheol Ahn, Juan Bascunan, Weijun Yao, and Yukikazu Iwasa, "Nonlinear Behavior of a Shim Coil an LTS/HTS NMR Magnet With an HTS Insert Comprising Double-Pancake HTS-Tape Coils," IEEE Trans. on Appl. Superconduct., vol.19, no.3, pp.2285-2288, Jun. 2009. https://doi.org/10.1109/TASC.2009.2018809
  6. Y. Yanagisawa, Y. Kominato, H. Nakagome, R. Hu, T. Takematsu, T. Takao, D. Uglietti, T. Kiyoshi, M. Takahashi, and H. Maeda, "Magnitude of the Screening Field for YBCO Coils," IEEE Trans. Appl. Supercond., vol.21, no.3, pp.1640-1643, Jun. 2011. https://doi.org/10.1109/TASC.2010.2087311
  7. D. I. Hoult, D. Lee, "Shimming a superconducting nuclear-magnetic-resonance imaging magnet with steel," Rev. of Sci. Inst., vol.1, no.56, pp.131-135, Aug. 1984.
  8. Frank X. Li, John P. Voccio, Min Cheol Ahn, Seungyong Hahn, Juan Bascunan and Yukikazu Iwasa, "An analytical approach towards passive ferromagnetic shimming design for a high-resolution NMR magnet," Supercond. Sci. Techol., vol.28, no.7, p.075006, May 2015. https://doi.org/10.1088/0953-2048/28/7/075006
  9. S. Iguchi, R. Piao, H. Hamada, S. Matsumoto, H. Suematsu, T. Takao, A. T. Saito, J. Li, H. Nakagome, X. Jin, M. Takahashi, H. Maeda, and Y. Yanagisawa, "Advanced field shimming technology to reduce the influence of screening current in a REBCO coil for a high-resolution NMR magnet," Supercond. Sci. Techol., vol.29, no.4, p.045013, Mar. 2016. https://doi.org/10.1088/0953-2048/29/4/045013
  10. Min Cheol Ahn, "Passive shimming design with commercially available rectangular shim sheets on a cylinder for HTS NMR magnets," Prog. Supercond. Cryogen., vol.20, no.2, pp.29-33, jun. 2018. https://doi.org/10.9714/PSAC.2018.20.2.029
  11. Jae Young Jang, Young Jin Hwang, Jun Hee Han, Minchul Ahn, Hongmin Yang, Seungyong Hahn, Jeseok Bang, and SangGap Lee, "Reproducibility of the field homogeneity of a metal-clad no-insulation all-REBCO magnet with a multi-layer ferromagnetic shim," Supercond. Sci. Techol., vol.33, no.2, p.025005, Jan. 2020. https://doi.org/10.1088/1361-6668/ab601d
  12. H. Glass, and L. Cooper, "Sequential Search: A Method for Solving Constrained Optimization Problems," Jour. of the ACM, vol. 12, no.1, pp. 71-82, Jan. 1965. https://doi.org/10.1145/321250.321256
  13. Kwang Lok Kim, Sangwon yoon, Kyekun Cheon, Jaemin Kim, Hunju Lee, SangGap Lee, Dong Lak Kim, and Seungyong Hahn, "400-MHz/60-mm All REBCO Nuclear Magnetic Resonance Magnet: Magnet Design," IEEE Trans. Appl. Supercond., vol.26, no.4, p.4302604, Dec. 2015.