Fabrication of a 25.2 T NMR magnet for an extreme condition user facility in China

Abstract

Abstract An ultra-high field magnet (> 20 T) is desirable to study material characteristics under extreme magnetic condition with the use of magnetic resonance for a higher signal-to-noise ratio, better sensitivity and a higher spectral resolution. The fabrication of an ultra-high field magnet requires high-temperature superconducting materials like REBSO and BSCCO, which have higher critical temperature and current density as compared to conventional low-temperature superconducting materials. Despite the benefits of BSCCO for better field homogeneity and stability due to its smaller screening currents, it is technically challenging to use it in magnet fabrication due to the greater variations in tape thickness and width. In this highlighted study, an optimization procedure was developed to randomly re-order the wound double-pancake coils as well as optimize the winding turns based on pre-winding measurements. Such optimizations enable the fabrication of a magnet with high homogeneity that is suitable for use in nuclear magnetic resonance.