Abstract
To standardize the test method for the critical current (Ic) measurement of three-component (Nb-Ti/Cu-Ni/Cu) superconducting wires, we have extracted many problems such as quenching, which often occurs in the wires, and have established a new measuring method. It was found that adding tension corresponding to a 0.1-0.2% strain applied to the wires is effective for preventing quenching than using silicone grease for fixing the wires to a mandrel, and that we can measure Ic's for all magnetic fields without quenching by soldering the wire to an alloy mandrel. It was also found that no trouble occurs when common Cu/Nb-Ti wires are measured based on the Ic test method of three-component wires. Therefore it is favorable to fix the wires by tension rather than using silicone grease in the case of wires which are easily quenched. Round robbin tests were carried out to check the validity of the draft for the test method. As a result of checking the coefficients of variation (COV) concerning individual experimental results, it was confirmed that the COV's reduce less than 2% in most cases. Based on these results, the draft of a test method for three-component wires was prepared.
