Reel-to-reel critical current measurement of coated conductors

We introduce an apparatus for non-destructive, contact free, reel-to-reel critical current measurement of coated conductor tape. Up to 100 m of tape can be passed in front of a sensor head for the measurement in liquid nitrogen. The tape is transferred and characterized at a speed of 10 mm s^-1. After the liquid nitrogen passage it is actively heated up to room temperature to avoid moisture condensation. Two different sensors in the probe head can be optionally activated: A linear Hall probe array in a field coil and an ac-measurement coil picking up third harmonic signals from the film. Once calibrated by transport measurement this arrangement enables characterization of HTS films on magnetic as well as on non-magnetic metal tape substrates. In a 10 mm wide coated conductor, up to 400 A of critical current can be measured.