Development of an electromagnetic microscope using HTS SQUIDs
Superconductive quantum interference devices (SQUIDS) offer new technology for eddy current evaluation of materials. Their high resolution at low frequencies enables arrays of small pickup loops that can give images of millimeter fatigue cracks, corrosion, and inclusions deep inside materials and structures, nondestructively. High temperature superconductors can bring the arrays into common use. They enable packaging them in a hand-held, refrigerated instrument, without cryogenic encumbrances. The instrument would be a hand held, electromagnetic microscope for eddy current evaluation of materials.