Effect of twist process on critical current and hysteresis loss of Nb₃Sn strands

We have prepared Nb₃Sn strands by the internal tin process for superconducting conductor application in the international thermonuclear experimental reactor (ITER). The multifilamentary Nb₃Sn strands have a diameter of 0.82 mm and a unit length longer than 5000 m. We have investigated the effect of twist process on superconducting critical current density and hysteresis loss for Nb₃Sn strands. It has been found that the twist process significantly reduces the hysteresis loss of the strands, while the critical current density and the n-value remain nearly unchanged.