Presentation Information
[AP1-05]42 T miniature all-HTS magnets for high-field NMR applications
*Chukun Gao1,2, Pin-Hui Chen1,2, Nicholas Alaniva2, James Ellison2, Snædís Björgvinsdóttir2, Edward Saliba2, Yanhui Hu2, Ioannis Pagonakis2, Alexander Däpp2, Ronny Gunzenhauser2, Michael Urban2, Alexander Barnes2 (1. Resonance Exploration Technologies (Switzerland), 2. Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich (Switzerland))
Keywords:
High-temperature superconductors,REBCO,compact magnet,nuclear magnetic resonance,screening currents,no-insulation coils,small-bore magnet
High magnetic fields are essential for advancing technologies across disciplines, including nuclear magnetic resonance (NMR) spectroscopy, fusion energy, and quantum materials research. However, access to ultra-high magnetic fields remains limited by the size, complexity, and power requirements of hybrid systems that combine low-temperature superconductors (LTS), high-temperature superconductors (HTS), and resistive magnets1–3. Fully HTS-based magnets offer a promising alternative by simplifying system architecture, but remain technically challenging due to conductor strain sensitivity, quench protection difficulties, and field inhomogeneity, especially in large-bore configurations4,5.
In this work, we propose and demonstrate miniature, all-HTS magnets with a record self-field and current density of 42 T and 1880 Amm-2, in a compact 3.1 mm bore quad pancake coil (Figure 1), an 80% increase over our previous reported 23 T6. To address critical challenges of small-bore HTS coil fabrication, including strain management, we designed and fabricated HTS magnets using a jointless, no-insulation winding technique 7, directly tested bending limits in coil form, and reinforced mechanical strength through soldering. In addition, the extreme bore reduction minimizes conductor usage and stored energy, enabling high-performance operation with improved thermal and electromagnetic stability. Magnetic field strength, homogeneity, and stability are characterized through in situ proton NMR measurements at 4.2 K.
While the 3.1 mm ultra-small bore is not directly compatible with current commercial NMR systems, this platform lays the groundwork for rethinking NMR probe architecture. By relocating auxiliary components outside the short magnet bore and leveraging emerging micro-NMR technologies, compact HTS magnets may enable new generations of high-field, energy-efficient NMR systems. Lastly, our miniaturized HTS magnets can serve as effective testbeds for exploring the field limits of HTS materials, offering insight into coil design, protection, and field homogeneity.
In this work, we propose and demonstrate miniature, all-HTS magnets with a record self-field and current density of 42 T and 1880 Amm-2, in a compact 3.1 mm bore quad pancake coil (Figure 1), an 80% increase over our previous reported 23 T6. To address critical challenges of small-bore HTS coil fabrication, including strain management, we designed and fabricated HTS magnets using a jointless, no-insulation winding technique 7, directly tested bending limits in coil form, and reinforced mechanical strength through soldering. In addition, the extreme bore reduction minimizes conductor usage and stored energy, enabling high-performance operation with improved thermal and electromagnetic stability. Magnetic field strength, homogeneity, and stability are characterized through in situ proton NMR measurements at 4.2 K.
While the 3.1 mm ultra-small bore is not directly compatible with current commercial NMR systems, this platform lays the groundwork for rethinking NMR probe architecture. By relocating auxiliary components outside the short magnet bore and leveraging emerging micro-NMR technologies, compact HTS magnets may enable new generations of high-field, energy-efficient NMR systems. Lastly, our miniaturized HTS magnets can serve as effective testbeds for exploring the field limits of HTS materials, offering insight into coil design, protection, and field homogeneity.