The Design and Operation of an 88-kG 20-in.-Bore Superconducting Magnet System

Lucas, Edward; Stekly, Z. J. J.; Winter, Tobias; Laurence, J. C.; Coles, Willard D

doi:10.1007/978-1-4757-0513-3_23

Cited by 2 publications

(4 citation statements)

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“…9 sc ReBCO Ag Typical  R values between ReBCO and Ag are in the range of 1-100×10 −14 Ωm 2 at 4.2 K and 0.7-3.7×10 −11 Ωm 2 at 77 K [16,19,20]. The current transfer length λ can be determined using the model by Lucas et al [21].…”

Section: Inter-strand Resistance Componentsmentioning

confidence: 99%

Inter-strand resistance and AC loss in resin-filler impregnated ReBCO Roebel cables

Gao

Dhallé

Nugteren

et al. 2019

Supercond. Sci. Technol.

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In the frame of the EuCARD2 collaboration, aimed at developing the technology for 20 T class accelerator magnets, several demonstrator dipole magnets are being built using high critical current density and fully transposed ReBCO tape-based Roebel-type cables. In accelerator magnets the dynamic magnetic field quality is one of the key parameters, which is affected by the effective interstrand resistances in the cables. For this reason, measurements of the inter-strand resistances on ReBCO Roebel cables were carried out at 4.2 and 77 K. Acquiring these data is also essential for input of cable simulation models. The cable samples are impregnated with epoxy resin to reduce the effect of transverse stress degradation due to Lorentz forces acting on the strands in the Roebel cables. The measured inter-strand resistance is used to estimate the AC coupling loss in different magnetic field orientations. Moreover, the contributions of diverse interface contact resistances to overall inter-strand resistance of Roebel cables were determined using a novel theoretical model. For validation, the AC loss of cables were examined in various orientations of applied field at 4.2 K. With three analytical models the hysteresis loss was calculated and compared to the measured data. The average inter-strand resistance of the cable samples impregnated with the unfilled epoxy CTD-101K range from 3 to 16 μΩ at 77 K and 1.5 to 9 μΩ at 4.2 K. Between the tapes the copper to copper interface resistance dominates the inter-strand resistance of impregnated Roebel cables. The calculated and measured AC loss for the CTD-101K impregnated Roebel cable lead to equivalent conclusions that the coupling loss is lower than the hysteresis loss within the range of the experiment. These observations substantially differ from earlier results extracted from a similar cable but impregnated with the alumina-filled epoxy resin CTD-101G, which showed considerable coupling loss when exposed to magnetic field parallel the wide face of the cable.

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Section: Inter-strand Resistance Componentsmentioning

confidence: 99%

Inter-strand resistance and AC loss in resin-filler impregnated ReBCO Roebel cables

Gao

Dhallé

Nugteren

et al. 2019

Supercond. Sci. Technol.

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“…We assume that we can 'unfold' the wire cross section into an upper metallic strip of width l t (the perimeter of the filament(s)) and thickness t n , separated from a bottom superconducting layer (the MgB 2 core(s)) by a thin resistive layer (figure 1). The problem then becomes quasi-1D, yielding a solution for the potential along the surface of the metal strip which is expressed by the equation [1,2]:…”

Section: Description Of the Transfer Modelmentioning

confidence: 99%

“…The process is characterized by the current transfer length, a conductor-dependent length scale that is essentially determined by the ratio between the transverse matrix-tofilament resistance and the longitudinal matrix resistance. In a straightforward model of a joint between a metal lead and a superconductor [1,2], the current in the lead decays exponentially on a length scale λ given by…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, Ishibashi et al [3] reported a systematic increase of the contact surface resistance in NbTi/Cu conductors with increasing heat treatment temperature (from R ≈ 10 −11 m 2 after heat treatment at 300 • C to 5 × 10 −11 m 2 after 600 • C), which they attributed to a high-resistivity diffusion layer of increasing thickness. Note that the values from [1,3] and [8] were recalculated with the aid of ( 1) and ( 2), converting the original data in terms of surface resistance R .…”

Section: Introductionmentioning

confidence: 99%

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Current transfer in MgB₂wires with different sheath materials

Holubek¹,

Dhallé²,

Kòváč³

2007

Supercond. Sci. Technol.

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The current transfer length in composite MgB2 wires with different metallic sheaths and filament numbers was analysed. The electric potential gradient along the wire in the vicinity of the current contact was monitored as a function of transport current in various external magnetic fields up to 14 T. In all samples the characteristic current transfer length is of the order of a millimetre, varying with detailed sheath composition in the range 0.35–2 mm. For the wires with a clear reaction layer at the filament/matrix interface, the electrical resistivity of the material constituting such a barrier was estimated.

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The Design and Operation of an 88-kG 20-in.-Bore Superconducting Magnet System

Cited by 2 publications

References 1 publication

Inter-strand resistance and AC loss in resin-filler impregnated ReBCO Roebel cables

Inter-strand resistance and AC loss in resin-filler impregnated ReBCO Roebel cables

Current transfer in MgB₂wires with different sheath materials

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The Design and Operation of an 88-kG 20-in.-Bore Superconducting Magnet System

Cited by 2 publications

References 1 publication

Inter-strand resistance and AC loss in resin-filler impregnated ReBCO Roebel cables

Inter-strand resistance and AC loss in resin-filler impregnated ReBCO Roebel cables

Current transfer in MgB2wires with different sheath materials

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Product

Resources

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Current transfer in MgB₂wires with different sheath materials