International Round Robin Test for Critical Current Measurement of RE-Ba-Cu-O Superconducting Tapes

VAMAS TWA 16 promoted an international round robin test (RRT) on critical current (I
_c
) measurement of RE-BaCu-O (REBCO; RE = rare earth) superconductors to establish the transport I
_c
measurement method in liquid nitrogen bath without an external magnetic field. Ten laboratories from five countries participated in the RRT and tested commercially available REBCO superconductors. I
_c
and measurement conditions were reported. In parallel, intrinsic I
_c
nonuniformity of the superconductors were evaluated by reel-to-reel scanning Hall-probe microscopy for 10-m conductors. Statistical analyses of I
_c
provided uncertainty of the measurement method. Combined standard uncertainty was analyzed considering the intrinsic nonuniformity of I
_c
. The analysis indicated that the intrinsic nonuniformity has the largest contribution to the uncertainty of I
_c
.