| 摘要 |
A nondestructive inspection apparatus having a SQUID is made with compact configuration and is capable of detecting a metallic or non-metallic metal for defects, corrosion, and the like, by forming the SQUID and a magnetic field applying coil on the same substrate. The SQUID comprises two Josephson junctions, a washer coil connected to the Josephson junctions to form a superconducting loop, shunt resistors, a damping resistor, and a feedback modulation coil, all of which are formed from a superconducting thin film on a supporting substrate. A magnetic field applying coil is formed on the same supporting substrate with a superconducting thin film or a normal conducting metal thin film. The magnetic field applying coil, which generally has plural turns around the SQUID, applies a dc or ac magnetic field to a sample. The change in magnetic field caused by a defect in the sample is detected by the washer coil, and the position and size of the defect may thus be determined. Since the magnetic field applying coil is integrated on the same substrate as that on which the SQUID is formed, the apparatus may be made compact.
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