26 T 35 mm all-GdBa₂Cu₃O_7–<i>x</i>multi-width no-insulation superconducting magnet

TLDR

The multi‑width no‑insulation high‑temperature superconductor winding technique enables a highly compact 172 mm diameter, 327 mm tall magnet. The 26‑T, 35‑mm diameter magnet was built from 26 no‑insulation double‑pancake coils of multi‑width GdBCO tapes (4.1–8.1 mm) and assembled by MIT’s Francis Bitter Magnet Laboratory and SuNAM Co., Ltd. At 77 K the magnet exhibited a 16‑minute charging time constant, while at 4.2 K it produced a record 26.4 T central field, demonstrating the strong potential of MW‑NI GdBCO magnets for DC high‑field use.

Abstract

A 26 T 35 mm winding diameter all-GdBa2Cu3O (GdBCO) magnet was designed by the MIT Francis Bitter Magnet Laboratory, and constructed and tested by the SuNAM Co., Ltd. With the multi-width (MW) no-insulation (NI) high temperature superconductor (HTS) winding technique incorporated, the magnet is highly compact; its overall diameter and height are 172 and 327 mm, respectively. It consists of a stack of 26 NI double pancake coils wound with MW GdBCO tapes in five different widths ranged 4.1–8.1 mm. In a bath of liquid nitrogen at 77 K, the magnet had a charging time constant of 16 min due to the intrinsic NI characteristics. In liquid helium at 4.2 K, the magnet generated a 26.4 T field at the center, a record high in magnetic fields from all-HTS magnets. The results demonstrate a strong potential of MW-NI GdBCO magnets for direct current high-field applications.