A Variable Temperature Cryostat to Measure J_nonCu(T) of ITER Strands up to 20 Teslas

摘要

The determination of the non-copper critical current density J_nonCu is crucial for the development of Nb_3Sn strands for ITER coils. The temperature dependence of J_nonCu in a magnetic field plays a leading part in determining the operating parameters and stability of the ITER coils. We describe the development of a variable temperature cryostat based on a new concept. This new cryostat is able to measure critical currents up to 600 A in fields up to 20 T in a temperature range of 4.2 K to 20 K.