A superconducting joint for GdBa2Cu3O7−δ-coated conductors

Park, Yeonjoo; Lee, Myungwhon; Ann, Heesung; Choi, Yoon Hyuck; Lee, Haigun

doi:10.1038/am.2014.18

Cited by 127 publications

(81 citation statements)

References 34 publications

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“…In particular, the yield of successful joints shall be above 95% minimum. Repeatable and reliable persistent joints for Bi:2212, Bi:2223, or ReBCO conductors had not been developed yet although there are reports describing successful attempts, for example [54]. …”

Section: Non-nbti Conductor Optionsmentioning

confidence: 99%

Conductors for commercial MRI magnets beyond NbTi: requirements and challenges

Parizh

Lvovsky

Sumption

2016

Supercond. Sci. Technol.

124

107

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Magnetic Resonance Imaging (MRI), a powerful medical diagnostic tool, is the largest commercial application of superconductivity. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition and lifecycle cost including service. In this paper, we analyze conductor requirements for commercial MRI magnets beyond traditional NbTi conductors, while avoiding links to a particular magnet configuration or design decisions. Potential conductor candidates include MgB2, ReBCO and BSCCO options. The analysis shows that no MRI-ready non-NbTi conductor is commercially available at the moment. For some conductors, MRI specifications will be difficult to achieve in principle. For others, cost is a key barrier. In some cases, the prospects for developing an MRI-ready conductor are more favorable, but significant developments are still needed. The key needs include the development of, or significant improvements in: (a) conductors specifically designed for MRI applications, with form-fit-and-function readily integratable into the present MRI magnet technology with minimum modifications. Preferably, similar conductors should be available from multiple vendors; (b) conductors with improved quench characteristics, i.e. the ability to carry significant current without damage while in the resistive state; (c) insulation which is compatible with manufacturing and refrigeration technologies; (d) dramatic increases in production and long-length quality control, including large-volume conductor manufacturing technology. In-situ MgB2 is, perhaps, the closest to meeting commercial and technical requirements to become suitable for commercial MRI. Conductor technology is an important, but not the only, issue in introduction of HTS / MgB2 conductor into commercial MRI magnets. These new conductors, even when they meet the above requirements, will likely require numerous modifications and developments in the associated magnet technology.

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Section: Non-nbti Conductor Optionsmentioning

confidence: 99%

Conductors for commercial MRI magnets beyond NbTi: requirements and challenges

Parizh

Lvovsky

Sumption

2016

Supercond. Sci. Technol.

124

107

View full text Add to dashboard Cite

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“…Currently, there is no practical superconducting joint technology for HTS-to-HTS and HTS-to-LTS and thus external current mode operation is inevitable for LTS/ HTS NMR magnets as shown in this paper. Recently, new methods for superconducting joints have been proposed [41,42] for REBCO conductors If those methods become practical, a self-persisting LTS/REBCO NMR magnet might be feasible; for this purpose, further investigation must be made on (a) the mechanical integrity and reasonable heat treatment time of the joint, and (b) a long REBCO conductor with a piece length of >1 km.…”

Section: Possibility Of a Self-persisting Magnet Operationmentioning

confidence: 99%

Operation of a 400 MHz NMR magnet using a (RE:Rare Earth)Ba2Cu3O7− high-temperature superconducting coil: Towards an ultra-compact super-high field NMR spectrometer operated beyond 1 GHz

Yanagisawa

Piao

Iguchi

et al. 2014

Journal of Magnetic Resonance

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High-temperature superconductors (HTS) are the key technology to achieve super-high magnetic field nuclear magnetic resonance (NMR) spectrometers with an operating frequency far beyond 1GHz (23.5T). (RE)BaCuO (REBCO, RE: rare earth) conductors have an advantage over BiSrCaCuO (Bi-2223) and BiSrCaCuO (Bi-2212) conductors in that they have very high tensile strengths and tolerate strong electromagnetic hoop stress, thereby having the potential to act as an ultra-compact super-high field NMR magnet. As a first step, we developed the world's first NMR magnet comprising an inner REBCO coil and outer low-temperature superconducting (LTS) coils. The magnet was successfully charged without degradation and mainly operated at 400MHz (9.39T). Technical problems for the NMR magnet due to screening current in the REBCO coil were clarified and solved as follows: (i) A remarkable temporal drift of the central magnetic field was suppressed by a current sweep reversal method utilizing ∼10% of the peak current. (ii) A Z2 field error harmonic of the main coil cannot be compensated by an outer correction coil and therefore an additional ferromagnetic shim was used. (iii) Large tesseral harmonics emerged that could not be corrected by cryoshim coils. Due to those harmonics, the resolution and sensitivity of NMR spectra are ten-fold lower than those for a conventional LTS NMR magnet. As a result, a HSQC spectrum could be achieved for a protein sample, while a NOESY spectrum could not be obtained. An ultra-compact 1.2GHz NMR magnet could be realized if we effectively take advantage of REBCO conductors, although this will require further research to suppress the effect of the screening current.

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“…Some of the methods that have been developed and reported by several groups are on the diffusion and solder joints. Recently, Park et al successfully achieved a resistance-free diffusion joint of GdBCO to GdBCO layer between two CC tapes, however the mechanical integrity of such joints have not yet been evaluated [69]. On the other hand, a practical solder jointing of Cu-stabilized CC tapes achieving a very low resistance of 10 nΩ by mechanically controlled joining method has been reported which showed a comparable electromechanical property with the single CC tape [70,71].…”

Section: Tape Joints For Device Applicationmentioning

confidence: 99%