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Description
Persistent joints using in-situ multifilamentary MgB2 wires have been developed. The joints were made using MRI style MgB2 wire. In order to test a joint, the wire was wound into a one turn coil and then connected by the place outside and away from the single turn coil. A hall sensor was placed in the coil to measure the field of the single turn as well as the decay of that field. After preparation, such samples would be cooled, a persistent current would be induced by a superconducting magnet into which the coil was placed, and its decay measured. These measurements were performed at 4.2 K as a function of a background field. A heater wire was also used to heat the wire and show the sudden drop of the persistent current to quantify the amount of current. Various joints were tested, typical results were 200-300 A of persistent current at self-field, 4 K, and resistance values of 5 x 10-12 . Substantial persistent currents were present up to 4 T with similar resistance values. The application to MgB2 MRI systems is discussed.