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magnetocardiography
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Design and Fabrication of an Integrated Superconducting Resonator/Flux Concentrator for rf SQUID Magnetometer
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mahdi (Supervisor)
Abstract
Ultra-sensitive magnetometers based on Radio Frequency Superconducting Quantum Interference Device (rf SQUID), have wide applications in Non-destructive Evaluation (NDE), geophysical measurements and biomagnetic measurements, especially in magnetocardiography (MCG) systems. A superconducting module coupled to rf SQUID is designed to provide a resonance frequency in GHz range (according to the electronic system frequency), as well as concentrating the magnetic flux in the effective area of SQUID. The signal can be measured through a port pumping AC power to the module. The resonator has been also implemented by lumped element tank circuits, but the quality factor of these circuits are usually...
Design and Fabrication of Sensor Probe and Active Noise Reduction Circuit for SQUID MCG System in Magnetically Unshielded Environment
,
M.Sc. Thesis
Sharif University of Technology
;
Fardmanesh, Mehdi
(Supervisor)
Abstract
Characterization of local magnetic activity of the heart muscles is named magnetocardiography (MCG), which measures magnetic field generated by electrical activity around heart. RF SQUID sensors are appropriate choice for measuring magnetic activity of the heart muscles. Because squid detects weak signals as low as fTesla, while heart magnetic field is near 50 pt which is one millionth of earth magnetic field and thousands of time weaker than the environment noise. One of the problems of mcg system is its urgency to shielding of unwanted magnetic field. In this project design of holders and resonators for well coupled input coil with RF SQUID is improved. As a result, at the first stage...
Design and Optimization of HTS SQUID based Magnetocardiography using Active Shield
, Ph.D. Dissertation Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
In this work, we report on a developed single-channel high-Tc SQUID based MCG system for operation in unshielded environment. In brief, our system consists of a liquid Nitrogen Dewar and two high-Tc rf-SQUID capsuled in a holding probe,which is connected via coaxial cables to our multichannel rf-SQUID readout electronics.The rf-SQUIDs were patterned from about 200 nm△10 nm thick YBCO films sputtered on 1 mm thick LaAlO3 substrates. The holding probe integrates rf-SQUIDs, LC resonant circuits, and shielding coils. We have investigated the effects of the lumped element tank circuit resonator parameters on the rf-SQUID signal characteristics and based on the simulation and experimental...
Design and optimization of feedback control system for active shielding of HTS RF-SQUID based MCG
, Article 24th Iranian Conference on Electrical Engineering, ICEE 2016, 10 May 2016 through 12 May 2016 ; 2016 , Pages 457-459 ; 9781467387897 (ISBN) ; Majzoubi, M ; Kalantari, N ; Fardmanesh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
A High Tc RF-SQUID Based magnetocardiography system is developed for operating in a passively unshielded environment, in which active shielding is implemented to compensate field noises for the low to midrange frequency range. The main part of the implemented active shield configuration is a feedback control system designed for environmental noise cancelation in particular that of the power lines. This control system includes two layers of inner and outer compensation coils with respect to the liquid Nitrogen Dewar as parts of the designed active shield. The inner coils are surrounding the HTS SQUIDs which are placed in axial gradiometric configuration inside the dewar. The outer coils are...
Low noise active shield for SQUID-based magnetocardiography systems
, Article IEEE Transactions on Applied Superconductivity ; Volume 28, Issue 4 , 2018 ; 10518223 (ISSN) ; Fardmanesh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
A light weight and low-cost active magnetic shield system is proposed for a single channel SQUID-based magnetocardiography system equipped for operating at liquid nitrogen temperature without passive magnetic shield. The developed active shield, using coils around the sensors, is a two-stage magnetic shielding system, each stage of which has been designed to compensate different frequency and dynamic ranges. The sensor part contains two high-Tc rf-SQUID magnetometers, capable of working stably under earth magnetic field, placed in an axial gradiometric arrangement with a baseline of 10 cm. The active shield setup is driven using two correlated proportional-integral-derivative closed loop...
Shielding factor enhancement method for Bi-stage active shield in SQUID-based magnetocardiography system
, Article 29th Iranian Conference on Electrical Engineering, ICEE 2021, 18 May 2021 through 20 May 2021 ; 2021 , Pages 129-133 ; 9781665433655 (ISBN) ; Esmaeili, F ; Shanehsazzadeh, F ; Fardmanesh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
We proposed a simple method to enhance shielding factor of our previously proposed bi-stage active shield system employed in a SQUID-based magnetocardiography system. The additional proposed design is optimized for canceling the power-line magnetic interference field to provide a calmer magnetic environment for the bi-stage active shield. A 50 Hz cancellation coil is placed around the bi-stage shielding system which includes inner and outer coils designed for compensating low-frequency (0-0.1Hz) and high-frequency (0.1-100Hz) environmental magnetic noise, respectively. In this configuration, a SQUID magnetometer is located at the center of these coils. Considering that the power-line...
Shielding factor enhancement method for bi-stage active shield in SQUID-based magnetocardiography system
, Article 29th Iranian Conference on Electrical Engineering, ICEE 2021, 18 May 2021 through 20 May 2021 ; 2021 , Pages 129-133 ; 9781665433655 (ISBN) ; Esmaeili, F ; Shanehsazzadeh, F ; Fardmanesh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
We proposed a simple method to enhance shielding factor of our previously proposed bi-stage active shield system employed in a SQUID-based magnetocardiography system. The additional proposed design is optimized for canceling the power-line magnetic interference field to provide a calmer magnetic environment for the bi-stage active shield. A 50 Hz cancellation coil is placed around the bi-stage shielding system which includes inner and outer coils designed for compensating low-frequency (0-0.1Hz) and high-frequency (0.1-100Hz) environmental magnetic noise, respectively. In this configuration, a SQUID magnetometer is located at the center of these coils. Considering that the power-line...
Environmental noise cancellation for high-TC SQUID-based magnetocardiography systems using a bistage active shield
, Article IEEE Transactions on Applied Superconductivity ; 2017 ; 10518223 (ISSN) ; Kalantari, N ; Sarreshtedari, F ; Fardmanesh, M ; Sharif University of Technology
Abstract
An active noise cancellation method is proposed for superconducting quantum interference devices (SQUID)-based magnetocardiography systems working out of magnetically shielded rooms. Using YBCO high-Tc rf-SQUID magnetometers as magnetic field sensors, an active shielding system was implemented based on this method. This method incorporates two different shielding frequency regimes of operation simultaneously. This is because the unwanted background magnetic field signals range from very low frequencies up to high frequencies with a wide range of amplitudes at the upper and lower frequency spectra. Therefore, the shielding system is designed in a bistage configuration, and each stage covers...
Model-based Bayesian filtering of cardiac contaminants from biomedical recordings
, Article Physiological Measurement ; Volume 29, Issue 5 , 2008 , Pages 595-613 ; 09673334 (ISSN) ; Shamsollahi, M. B ; Jutten, C ; Sharif University of Technology
2008
Abstract
Electrocardiogram (ECG) and magnetocardiogram (MCG) signals are among the most considerable sources of noise for other biomedical signals. In some recent works, a Bayesian filtering framework has been proposed for denoising the ECG signals. In this paper, it is shown that this framework may be effectively used for removing cardiac contaminants such as the ECG, MCG and ballistocardiographic artifacts from different biomedical recordings such as the electroencephalogram, electromyogram and also for canceling maternal cardiac signals from fetal ECG/MCG. The proposed method is evaluated on simulated and real signals. © 2008 Institute of Physics and Engineering in Medicine