2022 Volume 57 Issue 1 Pages 39-45
Research and development of superconducting magnesium diboride (MgB2) level sensor for liquid hydrogen have been conducted actively. Recently, the remarkably high performance of the external-heating-type MgB2 level sensor has been recognized. However, the performance of the long MgB2 level sensor based on a 100-m-long class MgB2 wire has not yet been tested, although the test is needed to produce the MgB2 level sensor for the large liquid hydrogen tank. Thus, we have fabricated 100-m-long class MgB2 wires, and evaluated their superconducting characteristics. Homogeneous elongation in the total length and uniform superconducting characteristics of the MgB2 wires were obtained. Using these MgB2 wires, we made 500-mm-long MgB2 level sensors and tested them. We obtained good level-detecting characteristics from those MgB2 level sensors. Thus, the production of the long MgB2 level sensor for the large liquid hydrogen tank is expected to be feasible.
