Affiliations: [a] Federal Institute for Materials Research and Testing,
BAM, Berlin, Germany | [b] Justus-Liebig-Universität, Gießen,
Germany
Correspondence:
[*]
Corresponding author: Dr. Marc Kreutzbruck, BAM, Division
VIII.4, Unter den Eichen 87, 12205 Berlin. Tel.: +49 30 8104 1840; Fax: +49 30
8104 1845; E-mail: marc.kreutzbruck@bam.de
Abstract: To meet the increasing fabrication quality standards and the high
throughput requirements NDE techniques are reliant on efficient reconstruction
tools and visualization tools. In this work we present an inverse algorithm for
a modern electromagnetic non-destructive testing approach using a small GMR
sensor array to inspect superconducting wires. Four sensitive GMR sensors are
positioned around the wire. Small defects of 100 μm in
size could be detected in a depth of 200 μm with a
signal-to-noise ratio of better than 400. Surface defects could be detected
with a SNR of up to 10,000. This remarkably SNR and the small extent of GMR
sensors results in a spatial resolution which offers new visualisation
techniques for defect localisation, defect characterization and future
tomography-like mapping techniques. We developed several inverse algorithms
based on either a Finite Element Method or an analytical approach leading to
defect localization with an accuracy of a few 10 μm.
