Transport performance of 1,000 A current lead prepared by the TFA-MOD processed YBCO tapes

Abstract

Superconductive current lead has been prepared by the TFA-MOD processed YBCO tapes. That is composed of 12 YBCO tapes having critical current (Ic) of around 100 A at 77 K. The tapes are 4.5 mm in width, 200 mm in length and about 120 μm in thickness. The 1 μm thick superconductive YBCO layer is formed on Hastelloy^TM substrate tape with buffer oxide layers through the TFA-MOD process. The 12 YBCO tapes are arrayed on the both sides (6 tapes on one side) of the stainless steel board with 3mm in thickness for a board type. They are similarly soldered to copper caps at the both ends.The transport current of 1,000 A was stably applied for 10 minutes 77K without any voltage. The transport current of 1,200 A was successfully applied without quenching. The voltage between both copper caps linerly increased with increasing the transport current, and it was about 300μV at the applied currents of 1,000A. The overall thermal conductivity of the current lead composed of YBCO tapes and stainless steel board is much lower than that of non-superconducting current leads. Therefore, the present current lead with small heat leakage seems to be practically promising for superconducting magnets.