Newly Designed 3 T MRI Magnet Wound With Bi-2223 Tape Conductors

We have designed and fabricated a 3T magnetic resonance imaging magnet system for the human brain, which was wound with Bi-2223 tape conductors. Cooled by a Gifford-McMahon cryocooler, it was operated at 20 K with a stored energy of 2.3 MJ. A magnetic-field homogeneity of 5 ppm was attained at 1.5 T, which was our target value. Using this Bi-2223 high-temperature superconducting magnet, we obtained magnetic resonance images in 1.5 T at 8.5 K. The system was successfully magnetized to 3 T, which is the final target field in our project. This work demonstrates the potential of the high-temperature superconducting magnet for use in human magnetic resonance imaging experiments.