400-MHz/60-mm All-REBCO Nuclear Magnetic Resonance Magnet: Magnet Design

Kim, Kwang Lok; Yoon, Sanghyun; Cheon, Kyekun; Kim, Jaemin; Lee, Hunju; Lee, SangGap; Kim, Dong Lak; Hahn, Seungyong

doi:10.1109/tasc.2015.2509172

Cited by 37 publications

(14 citation statements)

References 21 publications

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“…Especially, REBCO (Rare Earth Barium Copper Oxide) superconductors have demonstrated high critical temperature T c (91 K), high current density (>100 A at 4.2 K), high critical field (∼100 T), and large tension (>100 MPa). These high-performance REBCO tapes are used to develop a strong magnetic field in a compact volume [29,30,[37][38][39][40].…”

Section: T Axion Haloscopementioning

confidence: 99%

Axion Haloscope Using an 18 T High Temperature Superconducting Magnet

Yoon¹,

Ahn²,

Yang³

et al. 2022

Preprint

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We report details on the axion dark matter search experiment that uses the innovative technologies of a High-Temperature Superconducting (HTS) magnet and a Josephson Parametric Converter (JPC). An 18 T HTS solenoid magnet is developed for this experiment. The JPC is used as the first stage amplifier to achieve a near quantum-limited low-noise condition. The first dark matter axion search was performed with the 18 T axion haloscope [1]. The scan frequency range is from 4.7789 GHz to 4.8094 GHz (30.5 MHz range). No significant signal consistent with Galactic dark matter axion is observed. Our results set the best limit of the axion-photon-photon coupling (gaγγ) in the axion mass range of 19.764 to 19.890 µeV. Using the Bayesian method, the upper bounds of gaγγ are set at 0.98×|g KSVZ aγγ | (1.11×|g KSVZ aγγ |) in the mass ranges of 19.764 to 19.771 µeV (19.863 to 19.890 µeV), and at 1.76 ×|g KSVZ aγγ | in the mass ranges of 19.772 to 19.863 µeV with 90% confidence level, respectively. We report design, construction, operation, and data analysis of the 18 T axion haloscope experiment.

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Section: T Axion Haloscopementioning

confidence: 99%

Axion Haloscope Using an 18 T High Temperature Superconducting Magnet

Yoon¹,

Ahn²,

Yang³

et al. 2022

Preprint

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“…Higher magnetic field NMR magnets require expensive HTS REBCO tapes [4,5]. Even generating 400 MHz NMR magnets via REBCO tape is still expensive [6]. The disadvantage of the NbTi superconductor is its low critical temperature and critical current density at a high magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Design of a 9.4 T Superconducting Magnet for 400 MHz Nuclear Magnetic Resonance

Ren¹,

Li²,

Chen³

2022

Preprint

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A 9.4 T/400 MHz superconducting magnet with a warm bore of 60 mm is being designed. The 400 MHz NMR magnet is composed of 9 coaxial coils to generate a central field of 9.4 T. The magnetic field homogeneity is better than 4 ppm for 50 mm diameter spherical volume (DSV) and better than 1 ppb for 5 mm DSV. Three types of NbTi strands were used to reduce the cost of the superconducting materials. A preload with 80 MPa was exerted on the superconducting coils and over-banding with stainless steel was adopted to release the stress from the electromagnetic forces. The magnet will be operated in persistent mode with superconducting joints to reduce the field decay. The pulse tube cryocooler with a cooling capacity of 1 W at 4.2 K can be used to reduce the liquid helium evaporation and vibration during operation. The magnet will be equipped with Bi2223/AgAu HTS current leads to reduce the heat losses. In this paper, the design of the 9.4 T NMR superconducting coils, electromagnetic field calculations, and stress analysis of the superconducting coils were presented.

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“…This may represent the first use of an HTS magnet for a large-scale national accelerator facility. In fact, applications of HTS magnet are rapidly expanding beyond laboratory magnets to fusion [9][10][11] , high energy physics [12][13][14][15] , biochemistry [16][17][18][19][20][21] , biomedical diagnosis [22][23][24][25][26][27] , renewable energy [28][29][30][31] , electric propulsion [32][33][34][35] and more [36][37][38][39][40][41] .…”

Section: Introductionmentioning

confidence: 99%

“Thermal Eraser” to Mitigate Screening Current by Optimal Control on Spatial Temperature Distribution in a High Temperature Superconductor Magnet

Bang¹,

Kim²,

Lee³

et al. 2021

Preprint

Self Cite

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The so-called “screening current” in high temperature superconductor (HTS) is a well-known phenomenon that has detrimental effects on performance of an HTS magnet. To date, many research efforts have been devoted to suppressing screening current in an HTS magnet. Here we report a customized electric-heater, named “Thermal Eraser”, to mitigate the screening current. The key idea is to optimally control spatial temperature distribution in an HTS magnet using the customized heater and the consequent temperature-dependent local critical current of HTS wires of the magnet. To validate the idea, a Thermal Eraser was designed, constructed, and installed in an actual single-pancake HTS coil. And the Thermal Eraser plus test coil system was operated at temperatures ranging 7-40 K in our in-house conduction-cooling cryogenic facility. The feasibility of the Thermal Eraser was demonstrated in terms of two aspects: 1) creation of the designated spatial temperature distribution within the HTS test coil as designed; and 2) quantitative evaluation of its effectiveness to mitigate screening current using both experimental and numerical results. We confirmed that the screening current induced field in the test coil was reduced by 0.6 mT after activation of the Thermal Eraser, which implies 60% reduction of screening current in the HTS test coil. The results demonstrate that the Thermal Eraser is a viable option to effectively reduce the screening current in an HTS magnet.

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400-MHz/60-mm All-REBCO Nuclear Magnetic Resonance Magnet: Magnet Design

Cited by 37 publications

References 21 publications

Axion Haloscope Using an 18 T High Temperature Superconducting Magnet

Axion Haloscope Using an 18 T High Temperature Superconducting Magnet

Design of a 9.4 T Superconducting Magnet for 400 MHz Nuclear Magnetic Resonance

“Thermal Eraser” to Mitigate Screening Current by Optimal Control on Spatial Temperature Distribution in a High Temperature Superconductor Magnet

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