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Vol.2 , No. 6, Publication Date: Oct. 20, 2015, Page: 304-310
Ba <sub>2</sub>Cu <sub>3</sub>O <sub>x</sub> (REBCO) high-temperature superconducting (HTS) coil is a promising candidate to achieve a nuclear magnetic resonance (NMR) magnet operated at a magnetic field >23.5 Tesla (T), i.e. <sup>1</sup>H NMR frequency of 1 GHz. We developed and tested a 400 MHz (9.39 T) NMR magnet using an REBCO inner coil. The system included a low-temperature superconducting (LTS) shim coil inside the REBCO coil to compensate the large inhomogeneity of the magnetic field. After the magnet was successfully charged, and while the compensation of the magnetic field inhomogeneity was being carried out, the magnet was unexpectedly discharged due to a failure of the chiller used for the DC power supply. During the discharge, the magnetic flux was transferred from the main coil to the inner shim coil, and that coil quenched repeatedly due to the high induced current. After confirming that the coil was not damaged, the magnet was charged again and it was found that several components of the magnetic field inhomogeneity had increased compared to the previous operation. This phenomenon is explained as follows: the induced-current to the shim coil generated a large magnetic field and it added an undesired screening current in the REBCO coil, lead to the increase in the magnetic field inhomogeneity. The results suggest that a system to suppress the induced current is a requirement for a safe magnet operation and homogeneous magnetic field.&picture=http://www.aascit.org/aascit/decorators/img/journal/902.jpg)
| [1] | R. Piao, Graduate School of Engineering, Chiba University, Chiba, Japan. |
| [2] | Y. Yanagisawa, Graduate School of Engineering, Chiba University, Chiba, Japan. |
| [3] | J. Li, Graduate School of Engineering, Chiba University, Chiba, Japan. |
| [4] | A. T. Saito, Graduate School of Engineering, Chiba University, Chiba, Japan. |
| [5] | H. Nakagome, Graduate School of Engineering, Chiba University, Chiba, Japan. |
| [6] | S. Iguchi, Faculty of Science and Technology, Sophia University, Yotsuya, Japan. |
| [7] | T. Takao, Faculty of Science and Technology, Sophia University, Yotsuya, Japan. |
| [8] | M. Hamada, Japan Superconductor Technology Inc, Kobe, Japan. |
| [9] | S. Matsumoto, Superconducting Wire Unit, National Institute for Materials Science, Tsukuba, Japan. |
| [10] | H. Suematsu, JEOL RESONANCE Inc, Akishima, Japan. |
A RE(rare earth)Ba 2Cu 3O x (REBCO) high-temperature superconducting (HTS) coil is a promising candidate to achieve a nuclear magnetic resonance (NMR) magnet operated at a magnetic field >23.5 Tesla (T), i.e. 1H NMR frequency of 1 GHz. We developed and tested a 400 MHz (9.39 T) NMR magnet using an REBCO inner coil. The system included a low-temperature superconducting (LTS) shim coil inside the REBCO coil to compensate the large inhomogeneity of the magnetic field. After the magnet was successfully charged, and while the compensation of the magnetic field inhomogeneity was being carried out, the magnet was unexpectedly discharged due to a failure of the chiller used for the DC power supply. During the discharge, the magnetic flux was transferred from the main coil to the inner shim coil, and that coil quenched repeatedly due to the high induced current. After confirming that the coil was not damaged, the magnet was charged again and it was found that several components of the magnetic field inhomogeneity had increased compared to the previous operation. This phenomenon is explained as follows: the induced-current to the shim coil generated a large magnetic field and it added an undesired screening current in the REBCO coil, lead to the increase in the magnetic field inhomogeneity. The results suggest that a system to suppress the induced current is a requirement for a safe magnet operation and homogeneous magnetic field.
Keywords
Neculear Magnetic Resonance (NMR), High Magnetic Field, REBCO High-Temeprature Superconducting (HTS) Coil, Quench, Homogeneity of Magnetic Field
Reference
| [01] | D. W. Hazelton, V. Selvamanickam, J. M. Duval, D. C. Larbalestier, W. D. Markiewitcz, H. W. Weijers, and R. L. Holtz, Recent development in 2G HTS coil technology, IEEE Transactions on Applied Superconductivity, 19, 2218-2222, 2009. |
| [02] | Y. Yanagisawa, R. Piao, S. Iguchi, H. Nakagome, T. Takao, K. Kominato, M. Hamada, S. Matsumoto, H. Suematsu, X. Jin, M. Takahashi, T. Yamazaki, and H. Maeda, 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, Journal of Magnetic Resonance, 249, 38-48, 2014. |
| [03] | Y. Yanagisawa, H. Nakagome , D. Uglietti, T. Kiyoshi, Hu. Ruixin, T. Takematsu, T. Takao, M. Takahashi and H. Maeda, Effect of YBCO-coil shape on the screening current-induced magnetic field intensity, IEEE Transactions on Applied Superconductivity, 20, 744-47, 2010. |
| [04] | F. Romeo and D. I. Hoult, Magnetic field profiling: Analysis and correcting coil design, Magnetic Resonance in Medicine, 1, 44-65, 1984. |
| [05] | S. Iguchi et al., To be submitted to Superconductor Science and Technology. |
| [06] | R. Piao et al., High resolution NMR measurements for the 400 MHz (RE)Ba2Cu3O7-x high-temperature superconducting NMR magnet: Towards a compact super-high field NMR magnet operated beyond 1 GHz, Submitted to Journal of Magnetic Resonance. |
| [07] | Y. Yanagisawa, H. Nakagome, K. Tennmei, M. Hamada, M. Yoshikawa, A. Otsuka, M. Hosono, T. Kiyoshi, M. Takahashi, T. Yamazaki, and H. Maeda, Operation of a 500 MHz high temperature superconducting NMR: Towards an NMR spectrometer operating beyond 1 GHz, Journal of Magnetic Resonance, 203, 274-282, 2010. |
| [08] | S. Hahn, M. C. Ahn, J. Bascunan, W. Yao and Y. Iwasa, Nonlinear behavior of a shim coil in an LTS/HTS NMR Magnet with an HTS insert comprising doublepancake HTS-tape coils, IEEE Transactions on Applied Superconductivity, 19, 2285-88, 2009. |
| [09] | J. Bascunan, H. Lee, E. S. Bobrov and Y. Iwasa, A Low- and High-Temperature Superconducting NMR Magnet: Design and Performance Results, IEEE Transactions on Applied Superconductivity, 13, 1550-53, 2003. |
| [10] | S. Hahn, J. Bascuñán, H. Lee, E. S. Bobrov, W. Kim, M. C. Ahn and Y. Iwasa, Operation and performance analyses of 350 and 700 MHz low-/high-temperature superconductor nuclear magnetic resonance magnets: A march toward operating frequencies above 1 GHz, Journal of Applied Physics, 105, 024501, 2009. |
| [11] | D. F. Hillenbrand, K. M. Lo, W. F. B. Punchard, T. G. Reese, P. M. Starewicz, High-order MR shimming: a simulation study of the effectiveness of competing methods, using an established susceptibility model of the human head, Applied Magnetic Resonance, 29, 39-64, 2005. |
| [12] | Y. Iwasa, Case Studies in Superconducting Magnets (second ed.), Springer, p.458, 2009. |
| [13] | Y. Yanagisawa et al., Suppression of catastrophic thermal runaway for a REBCO innermost coil of an LTS/REBCO NMR magnet operated at 400–600 MHz (9.4-14.1 T), IEEE Transactions on Applied Superconductivity , 24, 4301005, 2014. |
