A new test station to measure the critical current of superconducting strands

A test station for critical current measurements of superconducting strands with lengths up to 1.6 m has been developed at LNCMI-Grenoble. A modular cryostat has been designed for its integration within the existing infrastructures of the laboratory including the 24 MW sites of resistive magnets for continuous magnetic fields up to 35 T. The sample holder can carry up to 10 strands wound in coils of 44 mm diameter and stacked up around a common current lead, which allows using the expensive magnet time more efficiently. To reduce the thermal load, a novel integrated switching unit containing 10 high current contactors operating in liquid helium has been implemented in order to connect alternately the remaining terminal of each strand sample to the second current lead. First results of critical current measurement obtained in a 10 T superconducting solenoid are presented. They allow the determination of the sensitivity and precision of this set-up. Finally, solutions to further improve this station are discussed .