Fast NDE of Superconducting Magnet Wires Using a Flow-Through SQUID Microscope

We have developed a cryocooled high-Tc SQUID microscope for fast non-destructive evaluation (NDE) of superconducting NbTi magnet wire. A feedthrough mechanism pulls the wire at speeds of up to 20 cm/s through a thin mylar tube that separates the room temperature wire from the SQUID. We present results on test wires where we detect defects down to about 0.3 mm diameter. Using analytical and numerical models, we extract information from the data, such as defect size and location. We describe a method for fast automated detection of defects in long wires.