Design & Implementation of Fluxgate Based Active Shield for Using in SQUID Based Magnetocardiograghy

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Razmkhah, Sasan | 2011

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 42647 (05)
University: Sharif University of Technology
Department: Electrical Engineering
Advisor(s): Fardmanesh, Mehdi
Abstract:
Superconducting Quantum Interference Devices (SQUIDs) are one of the most sensitive magnetic flux detectors. According to their high sensitivity, these sensors have many applications such as magnetic imaging, magnetocardiography and magnetoencephalography. In this project we have designed and implemented a fluxgate based active shield that would be used in magnetocardiography. One of the main concerns in RF-SQUID applications is suppression of the low and high frequency noises. These noise sources includes earth magnetic force, humming noise and RF noise caused by cell phones. These sources could unlock RF-SQUID sensors and hence needs to be shielded. Low frequency noise suppression could be very expensive and impractical using passive shields. In this project by fabrication of a high sensitivity fluxgate and using Helmholtz coils and implementation of the robust driver and controller circuits, an active shield for low frequencies was built. By incorporating the active shield and the passive shield for high frequencies, we achieve to the desired noise level for magnetocardiograghy
Keywords:
Superconductivity ; Superconducting Quantum Interference Device (SQUID) ; Magnetic Shielding ; Fetal Magnetocardiogram ; Fluxgate Magnetometer

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