Characterization of $\hbox{Nb}_{3}\hbox{Sn}$ Strands for a 40-T Hybrid Magnetic Model Coil

A 40-T hybrid magnet under construction at the High Magnetic Field Laboratory of the Chinese Academy of Sciences will use cable-in-conduit conductors for its superconducting outsert. The design necessitates the use of high current density (J
_c
) Nb
₃
Sn strands (J
_c
≥ 2100 A/mm
²
at 12 T/4.2 K). The high J
_c
restacked-rod-processed Nb
₃
Sn strand from Oxford Instruments Superconductor Technology was selected as one of the candidate strands. A series of tests was carried out to qualify the strand performance. Tests mainly included magnetization and critical current measurements as a function of axial strain, magnetic fields, and temperature. The test results are presented and discussed.