A Novel Short Sample Mounting Fixture for Critical Current Measurements

One of the essential characteristics of a superconducting wire is its critical current, defined as the maximal current at given temperature and magnetic field for which it remains superconducting. In order to make measurements from 1.8 K to 4.2 K and up to 1200 A at very low pressure, we studied and manufactured an original short sample mount; it is made of are two co‐axial current leads (46 mm and 24 mm of external diameter) terminating with two Nb3Sn buss bars. Annular space has been dimensioned in order to minimize the pressure drop for sub atmospheric operations (use of a 600 m3/h roots at 15 mbar with adjustable speed). The LHe supply is achieved with a transfer line covered with Kapton insulation. It is located inside the internal current lead and equipped with a JT valve. The sample to be measured, V A M A S type (Versailles project on Advanced MAterials and Standards), is assembled at the low end of the two buss bars. The quality of the electrical contacts is ensured by simple tightening. This pap...