Practical SQUID instrument for nondestructive testing
- 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, Vol. 71, Issue 11; Other Information: PBD: Sep 1997
- Country of Publication:
- United States
- Language:
- English
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