Detection of deep flaws by using a HTS-SQUID in unshielded environment

J. T. Jeng*, S. Y. Yang, H. E. Horng, H. C. Yang

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

32 Citations (Scopus)


We reported the nondestructive evaluation of flaws in conductive samples with the high-Tc SQUID operated at 77 K. By nulling the SQUID with an additional compensation, we can sensitively detect the excited magnetic field due to the eddy current around a deep flaw. To investigate the effects of the size and the depth of flaws on the induced magnetic field, the excited magnetic fields as a function of the depth were measured for buried slots with various widths and thickness. Besides, the amplitude and the phase with different excitation frequencies for a fixed slot size are also studied. It was found that for a fixed excitation frequency, the phase of the measured signal linearly responds to the depth of the slot, while the amplitude correlates with the height of the slot. The results are valuable for quantitative evaluation of flaws.

Original languageEnglish
Pages (from-to)1295-1298
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Issue number1 I
Publication statusPublished - 2001 Mar
Event2000 Applied Superconductivity Conference - Virginia Beach, VA, United States
Duration: 2000 Sept 172000 Sept 22


  • Depth
  • Nondestructive evaluation
  • Phase

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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