Dynamic Level-Detecting Characteristics of External-Heating-Type MgB2 Liquid Hydrogen Level Sensors Under Liquid Level Oscillation and Its Application to Sloshing Measurement

To establish the worldwide storage and marine transportation of hydrogen, it is important to develop liquid hydrogen tanks/carriers as well as a long level sensor such as a superconducting magnesium diboride (MgB 2 ) level sensor. An external-heating-type MgB 2 level sensor is expected to be an excellent choice for liquid hydrogen because of its high linearity, resolution, and reproducibility. The dynamic level-detecting characteristics of three 500-mm-long MgB 2 level sensors have been evaluated under conditions of oscillating liquid level using an optical cryostat and a high-speed microscope. The response time to variations of the liquid hydrogen level is about 0.1 s, and the difference between the level read optically and that detected by the MgB 2 level sensors is about 5 mm under these conditions. Thus, the MgB2 level sensors have superior response performance for the sloshing measurement of liquid hydrogen.