Practical SQUID instrument for nondestructive testing

Journal Article · Mon Sep 01 04:00:00 EDT 1997 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.119974· OSTI ID:542133

Tralshawala, N; Claycomb, J R; Miller, Jr, J H ^[1]

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1. Texas Center for Superconductivity, University of Houston, Houston, Texas 77204-5932 (United States)

We report on the development of a scanning eddy-current imaging system designed to detect deep subsurface flaws in conducting materials. A high transition temperature (high-T{sub c}) superconducting quantum interference device (SQUID) magnetometer is employed to provide the required sensitivity at low frequencies, while a combination of small cylindrical high-T{sub c} superconducting and {mu}-metal shields enable the instrument to be scanned in a magnetically noisy environment, rather than the object under test. The shields are arranged to prevent unwanted excitation and ambient noise fields from reaching the SQUID, and to enhance spatial resolution and minimize undesirable edge effects. Thus far, the instrument has successfully detected cracks and pits through 10 layers of aluminum, with a combined thickness of 5 cm at room temperature. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 542133
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 11 Vol. 71; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
66 PHYSICS
ALUMINIUM
CORROSION
CRACKS
EDDY CURRENT TESTING
EDDY CURRENTS
EROSION
HIGH-TC SUPERCONDUCTORS
MATERIALS TESTING
NONDESTRUCTIVE TESTING
SQUID DEVICES