Integrated low-temperature superconductor SQUID gradiometers for nondestructive evaluation

Klein, U., Walker, M.E., Carr, C., McKirdy, D.M., Pegrum, C.M., Donaldson, G.B., Cochran, A. and Nakane, H. (1997) Integrated low-temperature superconductor SQUID gradiometers for nondestructive evaluation. IEEE Transactions on Applied Superconductivity, 7(2), pp. 3037-3039. (doi: 10.1109/77.621972)

Abstract

We describe an eddy current nondestructive evaluation system using a low-temperature superconductor magnetic field sensor in an electromagnetically unshielded environment. The sensor comprises a niobium dc superconducting quantum interference device (SQUID) integrated with a first-order gradiometric pickup coil to reject spatially uniform interference fields but remain sensitive to flaw induced fields. We demonstrate its use in locating and mapping subsurface flaws in a multilayered aluminum structure using an eddy current excitation field at a frequency of 70 Hz, with no magnetic shielding around the specimen or cryostat.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cochran, Professor Sandy
• Authors: Klein, U., Walker, M.E., Carr, C., McKirdy, D.M., Pegrum, C.M., Donaldson, G.B., Cochran, A., and Nakane, H.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: IEEE Transactions on Applied Superconductivity
• Publisher: IEEE
• ISSN: 1051-8223
• ISSN (Online): 1558-2515