中国物理B ›› 2006, Vol. 15 ›› Issue (8): 1903-1908.doi: 10.1088/1009-1963/15/8/046

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High-Tc planar SQUID gradiometer for eddy current non-destructive evaluation

张鸣剑1, 彭智慧1, 陈莺飞1, 陈　珂1, 郑东宁1, 郎佩琳2   

  1. (1)National Laboratory for Superconductivity, Institute of Physics, and National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China; (2)National Laboratory for Superconductivity, Institute of Physics, and National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China;Department of Physics, Tsinghua University, Beijing 100084, China
  • 收稿日期:2006-02-09 修回日期:2006-04-03 出版日期:2006-08-20 发布日期:2006-08-20
  • 基金资助:
    Project supported by Ministry of Science and Technology of China (Grant Nos 2006CB601007 and 2002AA306412 ), National Nature Science Foundation of China (Grant No 10221002) and Chinese Academy of Sciences and National Center for Nanoscience and Technology, China.

High-Tc planar SQUID gradiometer for eddy current non-destructive evaluation

Zhang Ming-Jian(张鸣剑)a), Lang Pei-Lin(郎佩琳)a)b), Peng Zhi-Hui(彭智慧)a), Chen Ying-Fei(陈莺飞)a), Chen Ke(陈珂)a), and Zheng Dong-Ning(郑东宁)a)†   

  1. a National Laboratory for Superconductivity, Institute of Physics, and National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China; b Department of Physics, Tsinghua University, Beijing 100084, China
  • Received:2006-02-09 Revised:2006-04-03 Online:2006-08-20 Published:2006-08-20
  • Supported by:
    Project supported by Ministry of Science and Technology of China (Grant Nos 2006CB601007 and 2002AA306412 ), National Nature Science Foundation of China (Grant No 10221002) and Chinese Academy of Sciences and National Center for Nanoscience and Technology, China.

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摘要： This paper reports the fabrication and test of a high-Tc SQUID planar gradiometer which is patterned from YBCO thin film deposited on a SrTiO\xj{3} bicrystal substrate. The measurement of noise spectrum at 77K shows that the white noise at 200 Hz is about 1×10-4{\Phi0/\sqrt Hz. The minimal magnetic gradient is measured and the results suggest that the minimal magnetic gradient is 94 pT/m. The planar gradiometer is used in non-destructive evaluation (NDE) experiments to detect the artifacts in conducting aluminium plates by performing eddy current testing in an unshielded environment. The effect of the exciting coil dimension on the NDE results is investigated. By mapping out the induced field distribution, flaws about 10mm below the plate surface can be clearly identified.

关键词: SQUID, planar gradiometer, NDE

Abstract: This paper reports the fabrication and test of a high-Tc SQUID planar gradiometer which is patterned from YBCO thin film deposited on a SrTiO3 bicrystal substrate. The measurement of noise spectrum at 77K shows that the white noise at 200 Hz is about 1×10-4$\varPhi_0/\sqrt{\rm Hz}$. The minimal magnetic gradient is measured and the results suggest that the minimal magnetic gradient is 94 pT/m. The planar gradiometer is used in non-destructive evaluation (NDE) experiments to detect the artifacts in conducting aluminium plates by performing eddy current testing in an unshielded environment. The effect of the exciting coil dimension on the NDE results is investigated. By mapping out the induced field distribution, flaws about 10mm below the plate surface can be clearly identified.

Key words: SQUID, planar gradiometer, NDE

中图分类号:  (Superconducting quantum interference devices (SQUIDs))

  • 85.25.Dq
81.70.Ex (Nondestructive testing: electromagnetic testing, eddy-current testing)