A comparative study of triaxial and uniaxial magnetic shields made out of YBCO coated conductors

Wera, Laurent; Fagnard, Jean-François; Levin, Gilbert V.; Vanderheyden, Benoît; Vanderbemden, Philippe

doi:10.1088/0953-2048/28/7/074001

Cited by 16 publications

(11 citation statements)

References 33 publications

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“…The second category of interest includes shields made of 2nd generation (2G) coated conductor tapes. Since the shielding process relies on persistent shielding currents [33], the shield geometry should allow for a closed superconducting path, either across the width of the coated conductor [34][35][36], sometimes combined to bulk materials [37][38][39] or using 'eye-shaped' loops [40][41][42]. Moreover, the production of 2G coated conductor tapes has been significantly enhanced thanks to the so-called Rolling Assisted Biaxially Textured Substrate (RABiTS) as a template for depositing the HTS layer [43].…”

Section: Introductionmentioning

confidence: 99%

Magnetic shielding up to 0.67 T at 77 K using a stack of high temperature superconducting tape annuli of 26 mm bore

Brialmont

Dular

Wera

et al. 2023

Supercond. Sci. Technol.

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In this work we demonstrate the magnetic shielding ability of a stack of YBa2Cu3O7 (YBCO) tape annuli. The annuli are cut from a 46 mm wide second generation coated conductor deposited on a Ni-5at.%W alloy ferromagnetic substrate. The inner bore of the stacked tapes is 26 mm and the outer diameter is 45 mm. Three samples with different height (24 mm, 14.9 mm, 9.9 mm) are studied. All the experiments are carried out at both room temperature and liquid nitrogen temperature (77 K). The shielding efficiency is investigated when the magnetic field is applied either parallel to the axis of the stack (axial shielding) or perpendicular to it (transverse shielding). Under an axial field, magnetic shielding is found to be effective (SF > 3) up to magnetic flux densities of 0.67 T. The presence of the ferromagnetic substrates is found to have two important consequences. First, the stack of annuli is able to shield transverse flux densities in spite of its layered structure. Second, a finite magnetic shielding effectiveness is demonstrated at room temperature. In order to understand the contribution of the ferromagnetic substrates to the shielding mechanism, we use the experimental field dependence of the magnetic permeability as determined independently from hysteresis loop measurements on the same substrates. A finite-element homogenized model solved with an H-Φ formulation is shown to successfully reproduce the shielding factor of the stack at room temperature and 77 K, both under axial and transverse applied fields. These models are also used to assess the influence of the critical current density and the magnetic permeability on the shielding efficiency. Finally, the results are used to predict the magnetic shielding properties of higher stacks, demonstrating their significant potential to shield axial fields of ∼ 0.93 T (with SF > 10) at 77 K.

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Section: Introductionmentioning

confidence: 99%

Magnetic shielding up to 0.67 T at 77 K using a stack of high temperature superconducting tape annuli of 26 mm bore

Brialmont

Dular

Wera

et al. 2023

Supercond. Sci. Technol.

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“…Recently, tested solutions have included both active (i.e., a set of coils fed with appropriate currents [6]) and passive layouts (i.e., a simple superconducting cavity [7][8][9]). The latter ones, which exploit the intrinsic property of the SC materials, can be assembled using SC bulks [10][11][12] and/or SC coated conductors/tapes [13][14][15][16][17]. Furthermore, promising improvements of the shielding ability have been achieved by superimposing SC and ferromagnetic (FM) materials [18][19][20][21][22][23][24], including the possibility to cloak static (DC) and alternating (AC) magnetic fields in suitably shaped SC/FM heterostructures [25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Modelling and Performance Analysis of MgB2 and Hybrid Magnetic Shields

et al. 2022

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Superconductors are strategic materials for the fabrication of magnetic shields, and within this class, MgB2 has been proven to be a very promising option. However, a successful approach to produce devices with high shielding ability also requires the availability of suitable simulation tools guiding the optimization process. In this paper, we report on a 3D numerical model based on a vector potential (A)-formulation, exploited to investigate the properties of superconducting (SC) shielding structures with cylindrical symmetry and an aspect ratio of height to diameter approaching one. To this aim, we first explored the viability of this model by solving a benchmark problem and comparing the computation outputs with those obtained with the most used approach based on the H-formulation. This comparison evidenced the full agreement of the computation outcomes as well as the much better performance of the model based on the A-formulation in terms of computation time. Relying on this result, the latter model was exploited to predict the shielding properties of open and single capped MgB2 tubes with and without the superimposition of a ferromagnetic (FM) shield. This investigation highlighted that the addition of the FM shell is very efficient in increasing the shielding factors of the SC screen when the applied magnetic field is tilted with respect to the shield axis. This effect is already significant at low tilt angles and allows compensating the strong decrease in the shielding ability that affects the short tubular SC screens when the external field is applied out of their axis.

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“…Some measurements in lower frequencies were also done 16 . Kvitkovic et al 17 and Wéra et al 18,19 analyzed the geometrical eects on the shielding quality. Kvitkovic et al also described the application of a planar magnetic shield to decrease the noise in the measurements of the magnetic eld 20 .…”

Section: Introductionmentioning

confidence: 99%

Improvement of the homogeneity of magnetic field by the attenuation of a selected component with an open superconducting shield made of commercial tapes

Kulikov

Kozlowski

Drobin

2019

Journal of Applied Physics

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Homogeneous magnetic fields are needed in many applications. The resolution of medical imaging techniques depends on the quality of the magnetic field, as does the efficiency of electron cooling systems used at particle accelerators. Current methods of improving homogeneity require complex arrangements of magnet windings. In this work, the application of commercial superconducting tapes for this purpose is analyzed experimentally and numerically. The shielding effect exhibited by the superconductors can be used to control the shape of the magnetic field. An open magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. To form a shield, the superconducting tapes are wound on a former. Then, it is positioned coaxially inside an electromagnet. The measurements are performed in the DC magnetic field and at zero-field cooling conditions. A numerical model is developed to further analyze the magnetic field. New simplifications and proper constraints allow the use of an axial symmetry despite relatively complex geometry of the shields. Results from the simplified model and obtained experimentally are consistent. The decrease of radial component of the magnetic field and the significant improvement of its homogeneity are observed in a shielded region. The decrease of shielding quality with the increase of an applied magnetic field is observed. Empirical formulas describing the dependence of shielding quality on the geometry and the critical current of the shield are developed.

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A comparative study of triaxial and uniaxial magnetic shields made out of YBCO coated conductors

Cited by 16 publications

References 33 publications

Magnetic shielding up to 0.67 T at 77 K using a stack of high temperature superconducting tape annuli of 26 mm bore

Magnetic shielding up to 0.67 T at 77 K using a stack of high temperature superconducting tape annuli of 26 mm bore

Modelling and Performance Analysis of MgB2 and Hybrid Magnetic Shields

Improvement of the homogeneity of magnetic field by the attenuation of a selected component with an open superconducting shield made of commercial tapes

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