9 T NbTi Cryogen Free HTS Test Stand

A 9 T conduction cooled superconducting magnet with 50 mm room temperature chamber is developed and tested. The system design allows to fill the chamber with liquid nitrogen. The system is based on a commercial two-stage 4 K Gifford-McMahon cryocooler with cooling power of 1.5 W at 4.2 K. The cool down time of the magnet from room temperature to 3.5 K is 18 hours. A pair of coated conductor based current leads is employed to reduce heat leak to the magnet. The main purpose of the magnet is critical current measurements for HTS wires. Using the magnetic system the angular dependence for short sample of coated conductor (SCS4050 from Superpower) and critical current of a small layer wound coil made of the same conductor were measured at 77 K in external magnetic field up to 4 T. The n-values for short sample are also presented. The measured critical current of the HTS coil in external magnetic field is up to 1.5 times lower than calculated one.