Untitled

Jeng, Jin-Tsong; Lee, Hsu Yang; Chen, Ji Cheng; Chen, Jau Han; Wu, Chi Hao; Hong, Yang; Horng, Herng Er

doi:10.1023/a:1022955304135

Cited by 4 publications

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to further study the characterization of this SQUID NDE system, cracks of different widths at different depths are evaluated in figure 4. From figure 4(a), it can be seen that the phase change , defined by tan −1 [(dB 90 • /dX)/(dB 0 • /dX)], in which X is the probe position [16], was independent of crack width, but increased linearly with the crack depth. Tthe intensity B r over the noise level of 8.5 ± 1.5 pT decayed exponentially with the depth in figure 4(b).…”

Section: Resultsmentioning

confidence: 99%

The characterization of a sensitive room-temperature probe for use in a SQUID nondestructive evaluation system

Chieh

Lin

Yang

et al. 2008

Supercond. Sci. Technol.

View full text Add to dashboard Cite

In this work, a SQUID nondestructive evaluation (NDE) system with outstanding mobility and performance is developed using two units connected by copper wire. One of those units is a SQUID unit consisting of a high-T c SQUID as well as a surrounding input coil, which are both cooled in liquid nitrogen and kept in a Dewar shielded by a cylindrical can with a shielding factor of 80-100 dB ranging from DC to 1 kHz. The other is a small, room-temperature probe composed of excitation coils and pickup coils. Based on the quadruple excitation field with the advantages of not only good balance of excitation noise but also a higher field gradient for enhancing the magnetic field distorted by small cracks underneath and a coplanar and differential coil with good ability to diminish the sensing of the magnetic field in the non-flaw region, the small and activated probe is made of quadruple excitation coils distributed in double D-shape differential pickup coils. The analysis shows that the SQUID NDE system using the novel probe design has advantages such as low thermal-noise introduction to the SQUID system, high transfer efficiency, efficient balancing of the excitation field as well as the dynamic noise during scanning, and high sensitivity, with a signal-to-noise ration (SNR) of 2 against the noise level of 8.5 ± 1.5 pT. This SQUID NDE system with the proposed probe is characterized by cracks with different widths at different depths, for example, fine spatial resolution up to 7 μm crack width on the surface of copper foil.

show abstract

Section: Resultsmentioning

confidence: 99%

The characterization of a sensitive room-temperature probe for use in a SQUID nondestructive evaluation system

Chieh

Lin

Yang

et al. 2008

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…[4][5][6] Other approaches that have been used involve planar SQUID gradiometers or utilize axial SQUID gradiometers for noise reduction. 6,7) However, such alternative methods are prohibitively expensive. No matter what type of SQUID NDE system that is developed, scanning still involves moving the massive Dewar filled with liquid nitrogen and the SQUID sensor integral to such a system, leading to problems with heavy dynamic loading and vibration.…”

Section: Introductionmentioning

confidence: 99%

Spatial Recognition of a Superconducting Quantum Interference Devices Nondestructive Evaluation System Using a Small Room-Temperature Probe

Chieh

Lin

Yang

et al. 2009

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

A superconducting-qantum-interference-device (SQUID) nondestructive evaluation (NDE) system using a small room-temperature probe is developed for active scanning rather than for a massive movement occurring in a traditional SQUID NDE system. The small room-temperature probe is composed of a quadruple excitation coil and a double D-shaped pickup coil. It is connected to the input coil surrounding a high-T(c) rf SQUID, immersed in liquid nitrogen, and shielded by a shielding can. Beyond the NDE function, the SQUID NDE scheme has spatial recognition functions, including the detection of the orientation and depth of a narrow line crack using different parameters, and the scanning of images of large objects with arbitrary shapes. Furthermore, the spatial sensitivity, limited by the size of the probe, reaches up to only 7 mu m in the aspect of crack widths and 1 mm in the aspect of spatial intervals for precision NDE on a printed circuit board. (C) 2009 The Japan Society of Applied Physic

show abstract