Robot-Based NDE System Using Movable HTS-SQUID Magnetometer Covered With HTS Film for Use in Unshielded Environment

Abstract

We developed a robust HTS-SQUID magnetometer utilizing bicrystal SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> substrates, single-layer YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7-x</sub> films and flip-chip technique, aiming for movable robot-based NDE system in unshielded environment. Robustness in the unshielded environment was achieved by coverage of the SQUID magnetometer with another cross-shaped HTS film in flip-chip configuration, and introduction of mesh structure in both the magnetometer and the HTS film. SQUID parameters, such as critical current 2I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> , resistance R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> /2, modulation voltage depth V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> , and flux noise S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Φ</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> , were measured in DC and AC fields. The SQUID magnetometer was rotated in unshielded environment, and moved by a robot arm, resulting in stable operation during the motion at 20 mm/s with active magnetic shielding technique.