Using a 77 K SQUID to measure magnetic fields for NDE

Cochran, A.; Macfarlane, J.C.; Morgan, L.N.C.; Kuznik, J.; Weston, R. G.; Hao, Ling; Bowman, R. M.; Donaldson, G.B.

doi:10.1109/77.317827

Cited by 32 publications

(5 citation statements)

References 9 publications

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“…Various methods of nondestructive evaluation for iron based materials have been investigated by several authors by observing ultrasonic propagation, X-ray methods, magnetic noise measurements [12], etc. Recently, by using SQUID and Hall devices, the magnetic leakage flux of strained samples has been intensively investigated [13][14][15].…”

Section: Magnetic Flux Leakage Measurementsmentioning

confidence: 99%

Nondestructive Material Evaluation by Novel Electromagnetic Methods

Vértesy

Gasparics

2003

MSF

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A high sensitivity magnetic field sensor, which has recently been developed, is applied for non-destructive testing. The sensor can be effectively utilized for the detection of defects in conducting materials using eddy current testing measurements. The principle of this measuring technique is based on the combination of the detection of changes in the eddy current magnetic field and the variation of magnetic polarization of the sample due to the presence of the defect. The capability of this technique has been demonstrated by measurements performed on different specimens. The sensor was also applied for measuring the magnetic leakage in plastically deformed, ferromagnetic, low alloy steel samples. High resolution and high sensitivity were achieved, strong inhomogeneities were revealed in the investigated sample, and the fine structure of the magnetic flux distribution was detected.

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Section: Magnetic Flux Leakage Measurementsmentioning

confidence: 99%

Nondestructive Material Evaluation by Novel Electromagnetic Methods

Vértesy

Gasparics

2003

MSF

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“…Donaldson and co-workers at Strathclyde have been working on high-T c SQUID systems for several years. Their developmental work includes a bulk high-T c instrument without SQUIDs [111], using a bare SQUID to map the field above a current pattern [112], fabrication of high-T c SQUIDs [113], and using a bare commercial SQUID in a special LN 2 Dewar for eddy-current mapping [114]. Most recently, they have published NDE results using a two-SQUID electronic gradiometer with the sample in motion [66,67] as well as with the SQUID in motion [115].…”

Section: Squid Systems For Ndementioning

confidence: 99%

SQUIDs for nondestructive evaluation

Jenks

Sadeghi

Wikswo

1997

J. Phys. D: Appl. Phys.

141

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We attempt a comprehensive review of all published research in nondestructive evaluation (NDE) performed with the superconducting quantum interference device (SQUID) magnetometer since the first work was reported in the mid-1980s. The SQUID is the most sensitive detector of magnetic flux known. The energy sensitivity of the SQUID may make it the most sensitive detector of any kind. The research on SQUIDs for NDE is based on the promise of that sensitivity and on the various other desirable properties developed for SQUID instrumentation in biomagnetism and other fields. The sensitivity of SQUID instruments down to very low frequencies allows them to function as eddy-current sensors with unparalleled depth resolution, and to image the static magnetization of paramagnetic materials and the flow of near-dc corrosion currents. The wide dynamic range of the SQUID makes it possible to image defects in steel structures and to measure the magnetomechanical behaviour of ferromagnetic materials with high sensitivity. In the last decade SQUID instrumentation designed specifically for NDE has appeared and improved the spatial resolution of most work to roughly 1 mm, with promise of another order of magnitude improvement within the next five years. Algorithms for flaw detection and image deconvolution have begun to flourish. With many talented, industrious people in the field, the future of SQUID NDE looks bright, provided the crucial first niche can be found.

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“…The cryostat is suspended on a wooden frame above a computer controlled, magnetically quiet x-y scanning system. 10 It is located in a conventional research laboratory, with nearby rotary pumps, computers, power wiring, and other disturbances.…”

Section: ͓S0003-6951͑97͒03927-2͔mentioning

confidence: 99%