MgB₂-based superconducting wire for a liquid hydrogen level sensor, a liquid hydrogen level sensor, and a liquid hydrogen level gauge

摘要

An MgB₂-based superconducting wire for a liquid hydrogen fluid level sensor which can maintain an unimmersed portion of the MgB₂-based superconducting wire for a liquid hydrogen fluid level sensor in a non-superconducting state even without heating the unimmersed portion is provided. A wire for a liquid hydrogen fluid level sensor comprises an MgB₂-based superconductor which contains Mg, B, and Al. The critical temperature at which the electrical resistance becomes essentially zero is 20-25 K, and the transition width, which is the difference between the temperature at which the electrical resistance begins to decrease toward zero and the critical temperature, is at most 5 K.