Gradient coil design using Bi-2223 high temperature superconducting tape for magnetic resonance imaging

Bi-2223 tape is a low-cost, long-length high temperature superconducting material. The new application of Bi-2223 tape for gradient coils for magnetic resonance imaging (MRI) is studied in this paper. Because Bi-2223 tape has a much higher critical current density and a much lower power loss than copper, a Bi-2223 high temperature superconductor (HTS) gradient coil shows great advantages in high gradient strengths, long continuous gradient rating, and free of cooling system over a copper gradient coil. The power losses of Bi-2223 tapes at working frequencies of gradient coils are compared to copper. The critical current degradation of tapes is also discussed. A prototype of HTS tape gradient coil is fabricated and its gradient field distributions are measured. Technical issues of resistance, gradient strength, continuous gradient rating, and cryostat are also discussed.