MgB2 Superconducting Joint Architecture with the Functionality to Screen External Magnetic Fields for MRI Magnet Applications

초록

A superconducting joint architecture to join unreacted carbon-doped multifilament magnesium diboride (MgB2) wires with the functionality to screen external magnetic fields for magnetic resonance imaging (MRI) magnet applications is proposed. The intrinsic diamagnetic property of a superconducting MgB2 bulk was exploited to produce a magnetic field screening effect around the current transfer path within the joint. Unprecedentedly, the joint fabricated using this novel architecture was able to screen magnetic fields up to 1.5 T at 20 K and up to 2 T at 15 K and thereby almost nullified the effect of the applied magnetic field by maintaining a constant critical current (I-c). The joint showed an I-c of 30.8 A in 1.5 T at 20 K and an ultralow resistance of about 3.32 x 10(-14) Omega at 20 K in a self-field. The magnetic field screening effect shown by the MgB2 joint is expected to be extremely valuable for MRI magnet applications, where the I-c of the joints is lower than the I-c of the connected MgB2 wires in a given magnetic field and temperature.

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