Title :
A four channel HTS SQUID NDE system
Author :
Lee, S.-M. ; Lee, Hyung Jong ; Choi, D.-J. ; Lee, H.J. ; Oh, B.
Author_Institution :
LG Electron. Inst. of Technol., Seoul, South Korea
fDate :
6/1/2003 12:00:00 AM
Abstract :
We have constructed an NDE system using an array of four HTS SQUID sensors. The sensor array was fabricated on a SrTiO3 bi-crystal substrate. The SQUID pickup loops were held perpendicular to the device under test. The lateral dimension of the SQUID was 20 micrometers and the noise was typically less than 30 pT/Hz12/ at 10 Hz. We used modulation FLL circuits for SQUID readout. The effect by modulation and feedback coupling between adjacent channels was investigated by measuring noise spectrum and output change with and without operating adjacent channels. We applied the system to map the magnetic field generated by current distribution and magnetic inclusions in a working circuit as well as a current carrying metal pattern.
Keywords :
SQUIDs; current distribution; high-temperature superconductors; magnetic sensors; nondestructive testing; 10 Hz; 20 micron; HTS SQUID sensors; NDE system; SrTiO3; adjacent channels; bi-crystal substrate; current carrying metal pattern; current distribution; device under test; feedback coupling; lateral dimension; magnetic inclusions; magnetic sensors; modulation FLL circuits; noise spectrum; output change; pickup loops; sensor array; Circuit noise; Circuit testing; Coupling circuits; Frequency locked loops; High temperature superconductors; Magnetic field measurement; Output feedback; SQUIDs; Sensor arrays; Sensor systems;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.813684
