A Comparison of Squid Imaging Techniques for Small Defects in Nonmagnetic Tubes

Imaging Subsurface Defects Using SQUID Magnetometers

“…It is especially suitable for a SQUID with a pick-up coil measuring the vertical component. This technique has great potential for detection of subsurface defects in planar metal structures and thin-walled conducting tubes [5].…”

“…By injecting a spatially uniform current into the conductors, such as a plate [2,3,4] or a thin-walled tube [5], and measuring the normal component of the magnetic field using a SQUID magnetometer, we can determine the dimensions and the location of the defects. Figure 1 is the calculated contour maps of the normal component of the magnetic field for a 12 mm long slot with angle of 90 0 , 30 0 , 100 and 0 0 with respect to the current injected in the y direction.…”

Detection of Thermal Aging of Duplex Stainless Steels With Squid Magnetometer

“…Although SQUIDs provide an exquisitely sensitive means to measure magnetic fields, their usage in the past has been chiefly limited to measurement of biomagnetic fields produced by the human heart, brain and other organs [7]. Recently, however, SQUs are used for nondestructive evaluation of materials and structures [8][9][10][11][12][13].…”