Optimum Copper Stabilizer Thickness for Symmetric Tape Round (STAR) REBCO Wires With Superior Mechanical Properties for Accelerator Magnet Applications

Kar, Soumen; Luo, Wenbo; Sandra, Jithin Sai; Majkic, Goran; Selvamanickam, V.

doi:10.1109/tasc.2019.2912312

Cited by 9 publications

(12 citation statements)

References 20 publications

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“…The copper stabilizer was electroplated primarily on the REBCO film side so as to position the film at the neutral plane. The copper thickness was adjusted to (18-30 µm) based on the substrate thickness as described in reference [28].…”

Section: Characteristics Of 50 M Long Symmetric Rebco Tapesmentioning

confidence: 99%

“…A challenge with REBCO coated conductors as compared to Nb-Ti, Nb 3 Sn and Bi-2212 wires is associated with their flat rather than round geometry and wide (~12 mm) profile rather than multifilamentary architecture. This challenge has been overcome using symmetric REBCO tapes wherein the REBCO film is positioned at the neutral plane [27][28][29][30][31][32][33]. Due to the excellent bend tolerance of the REBCO symmetric tapes, the flat REBCO tape geometry can be converted to round wire by the helical winding of narrow tapes on a round former as small as 0.51-1.02 mm [27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

“…This challenge has been overcome using symmetric REBCO tapes wherein the REBCO film is positioned at the neutral plane [27][28][29][30][31][32][33]. Due to the excellent bend tolerance of the REBCO symmetric tapes, the flat REBCO tape geometry can be converted to round wire by the helical winding of narrow tapes on a round former as small as 0.51-1.02 mm [27][28][29][30]. AMPeers and the University of Houston demonstrated symmetric tape round (STAR™) REBCO wires as small as 1.3-1.9 mm in diameter, suitable for bending at a 15 mm radius with >90% I c retention, with a record J e of 586 A mm −2 at 20 T, 4.2 K [31].…”

Section: Introductionmentioning

confidence: 99%

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Progress in scale-up of REBCO STAR™ wire for canted cosine theta coils and future strategies with enhanced flexibility

Kar

Sandra

Luo

et al. 2020

Supercond. Sci. Technol.

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We report recent developments in the scale-up of symmetric RE-Ba-Cu-O (REBCO) tapes with 15-22 µm thick substrates. Using these symmetric REBCO tapes, we fabricated up to 10 m long, symmetric tape round (STAR™) REBCO wires, less than 2 mm diameter, using 1.02 mm and 0.81 mm diameter copper formers. The critical current of the long STAR™ wires made in lengths of 2-10 m ranges from 465 A to 564 A at 77 K, self-field. This wire was then used to construct a single-layer, full-depth groove, three-turn canted cosine theta (CCT) coil with a minimum bend radius of 15 mm. This three-turn CCT coil retains 95% of its I c even when wound at a such a small bend radius. This result confirms the capability of fabricating CCT coils with STAR™ wire at a tilt angle of 30º which would yield a dipole transfer function of 0.48 T kA −1 at a 15 mm bend radius. Further, the architecture of STAR™ wire was modified for an I c retention of >90% at an even smaller bend radius of 10 mm with the aim of increasing the dipole transfer function. The higher dipole transfer function enabled by STAR™ wire is an important step toward the eventual goal of a 5 T maximum dipole field in a REBCO-based CCT coil. At a bend radius of 10 mm, a six-layer STAR ™ wire exhibits a critical current of 288 A at 77 K, self-field, i.e. 94% I c retention and 617 A at 4.2 K in a 15 T background field, which equals a J e of 412.7 A mm −2 at a Lorentz force of 9.3 kN m −1 . This level of flexibility and the high performance of STAR ™ wire in high fields at 4.2 K and with a small bend radius underscores its potential use in compact and low-cost high-field magnet and related applications.

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Section: Characteristics Of 50 M Long Symmetric Rebco Tapesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Progress in scale-up of REBCO STAR™ wire for canted cosine theta coils and future strategies with enhanced flexibility

Kar

Sandra

Luo

et al. 2020

Supercond. Sci. Technol.

Self Cite

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show abstract

“…First, reduce the current density in the normal metal (such as the Cu stabilizer electroplated around the REBCO tape) during a transition. For round REBCO conductors such as CORC R and STAR wires, it would be useful for the metal former to carry most of the current during the transition since it occupies 30%-90% of the conductor cross-sectional area (Table 1) [38,160].…”

Section: How Do Rebco Accelerator Magnets Transit From Superconductinmentioning

confidence: 99%

“…Understanding how strain develops in REBCO layer during the cabling and magnet winding processes will be critical [32,104,106,[108][109][110]195,196]. The design tools based on the understanding of the conductor mechanics will help guide the development of more flexible round REBCO conductors and the optimized REBCO tapes with thinner substrates and narrower widths [34,38,160]. It is also important to systematically measure the impact of electromagnetic loads on conductors and to understand and mitigate potential conductor degradation.…”

Section: What Is the Required Performance For Rebco Conductors To Achmentioning

confidence: 99%

Dipole Magnets above 20 Tesla: Research Needs for a Path via High-Temperature Superconducting REBCO Conductors

2019

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To enable the physics research that continues to deepen our understanding of the Universe, future circular colliders will require a critical and unique instrument—magnets that can generate a dipole field of 20 T and above. However, today’s maturing magnet technology for low-temperature superconductors (Nb-Ti and Nb 3 Sn) can lead to a maximum dipole field of around 16 T. High-temperature superconductors such as REBCO can, in principle, generate higher dipole fields but significant challenges exist for both conductor and magnet technology. To address these challenges, several critical research needs, including direct needs on instrumentation and measurements, are identified to push for the maximum dipole fields a REBCO accelerator magnet can generate. We discuss the research needs by reviewing the current results and outlining the perspectives for future technology development, followed by a brief update on the status of the technology development at Lawrence Berkeley National Laboratory. We present a roadmap for the next decade to develop 20 T-class REBCO accelerator magnets as an enabling instrument for future energy-frontier accelerator complex.

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Preparing pure C-axis oriented SrTiO3 film on CeO2 film by introducing a nano-Y0.5Gd0.5Ba2Cu3O7- layer

Liu

et al. 2020

Ceramics International

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Optimum Copper Stabilizer Thickness for Symmetric Tape Round (STAR) REBCO Wires With Superior Mechanical Properties for Accelerator Magnet Applications

Cited by 9 publications

References 20 publications

Progress in scale-up of REBCO STAR™ wire for canted cosine theta coils and future strategies with enhanced flexibility

Progress in scale-up of REBCO STAR™ wire for canted cosine theta coils and future strategies with enhanced flexibility

Dipole Magnets above 20 Tesla: Research Needs for a Path via High-Temperature Superconducting REBCO Conductors

Preparing pure C-axis oriented SrTiO3 film on CeO2 film by introducing a nano-Y0.5Gd0.5Ba2Cu3O7- layer

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