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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 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 Optimization of RSFQ Based Digital SQUID for High Sensitive Measurement of Widely Varying Magnetic Fields
, Ph.D. Dissertation Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Analog SQUIDs have limited slew rate and dynamic range and these problems make it hard to operate SQUID systems in unshielded applications like Bio-magnetic imaging and NDE. Recently by combining analog SQUIDs and RSFQ Logic, new class of magnetic sensors are introduced. These sensors have an acceptable sensitivity and very high dynamic range. On the other hand these sensors, Which are called Digital SQUIDs, can be directly connected to digital signal processing stages. In This work, for first time, a digital SQUID completely based on i-directional RSFQ was designed and optimized. using Bi-directional RSFQ, one can significantly simplify the digital SQUID circuit design and therefore...
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...
Optimization of SQUID NDE for Detection of the Defects in Metallic Samples
, Ph.D. Dissertation Sharif University of Technology ; Fardmanesh, Mahdi (Supervisor) ; Kokabi, Hamid (Supervisor)
Abstract
The purpose of this thesis is the incorporation of RF SQUID ultra-sensitive magnetic sensors in an implemented SQUID NDE system and also the development of associated inverse solution algorithms for the detection of defects in metallic samples. The system is based on the induction of Eddy currents and the incorporation of SQUIDs for precise detection of the magnetic field anomalies related to the defects in the sample. One of the major parts of the system is the highly stable, multi-channel RF SQUID readout system which has been designed and implemented with novel features for this project. For the magnetic inverse analysis of our SQUID NDE measurements, new models have been presented for...
Design and Implementation of Vibrating Sample Magnetometer Based on Gradiometer RF SQUID
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
The aim of this project is design and implementation of the “gradiometer RF SQUID base Vibrating Sample Magnetometer (VSM)”. Different sections of the system have been designed such as pick up coils, vibration system and electronic circuits. The piezoelectric crystal has been concerned for vibration system. At the first step, we have implemented the basic VSM system. In the basic system, voltage induces in two series opposite pick up coils and its output is recognizable via electronic circuits. At the second phase of the project, the electronic circuits of basic VSM system have been replaced with the RF SQUID gradiometer and its electronic circuits. Afterwards, the sensitivity and the gain...
Design & Implementation of Fluxgate Based Active Shield for Using in SQUID Based Magnetocardiograghy
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
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...
Design and Implementation of a SQUID Based Magnetic Detection System Using Active and Passive Shielding
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mahdi (Supervisor)
Abstract
Superconducting SQUID sensors are one of the most sensitive magnetic sensors that have been ever produced. Due to their high sensitivity, these sensors have many applications in different fields. Magnetic Imaging and far away targets detections are of these applications. In this project, a magnetic imaging system based on Superconducting SQUID sensors have been designed and implemented. In SQUID applications one of the most important problems is the cancelation of the unwanted fields including background low frequency and high frequency fields. In residential and urban areas the interference of Electricity network is considered as one of the major noise sources. While the high frequency...
Design and optimization of fully digital SQUID based on bi-directional RSFQ
, Article Journal of Superconductivity and Novel Magnetism ; Vol. 27, issue. 7 , 2014 , p. 1623-1628 ; Bozbey, A ; Fardmanesh, M ; Sharif University of Technology
Abstract
Bi-directional RSFQ benefits from using both positive and negative SFQ pulses to manipulate and transfer digital data. This allows more flexibility in the design of simpler circuits with enhanced performance. On the other hand, using the AC bias current, one can replace on-chip resistive current distributors with inductors. This resembles RQL logic, but in contrast to RQL, it is possible to use the well-established standard RSFQ cells in bi-directional RSFQ. These two advantages (energy-efficient computation and flexibility in design) make bi-directional RSFQ a powerful tool in next-generation supercomputers and also compatible with ultra-low-temperature quantum computers. In this work, to...
On the effect of cooling rate during melt spinning of FINEMET ribbons
, Article Nanoscale ; Volume 5, Issue 16 , 2013 , Pages 7520-7527 ; 20403364 (ISSN) ; Hosseini, H. R. M ; Davami, P ; Ostadhossein, F ; Song, M ; Gjoka, M ; Sharif University of Technology
2013
Abstract
The effect of quenching wheel speed on the structure and Curie temperature of Fe73.5Si13.5B9Nb3Cu1 alloy has been investigated using X-ray diffraction, differential scanning calorimetry, transition electron microscopy and a SQUID magnetometer. Ribbons were melt-spun at different wheel speeds and then were annealed to nucleate nano crystals embedded in the amorphous matrix. The results indicated that the thickness of the ribbons was inversely proportional to the wheel speed following the power law of the type t ∝ Vs -1.231. DSC and XRD results showed that at higher wheel speeds the greater potential energy triggers the formation of Fe (Si) crystallites and thus, increases the crystallinity....
Crosstalk suppression and high-fidelity measurement in 2-D tunneling of coupled Josephson junctions
, Article IEEE Transactions on Applied Superconductivity ; Volume 22, Issue 4 , 2012 ; 10518223 (ISSN) ; Zandi, H ; Khorasani, S ; Sharif University of Technology
2012
Abstract
We present a new configuration concept in which two similar Josephson junctions are coupled through a capacitor placed in parallel to a dc-superconducting quantum interference device (SQUID) to improve the characteristics of phase qubits. In real coupled quantum systems, because of mutual effects such as crosstalk, entangled quantum states cannot be independently measured. The proposed two-qubit system is demonstrated to have a negligible crosstalk, obtained from the application of a single measurement pulse and an appropriate external flux to one of the junctions and the dc-SQUID, respectively. Surprisingly, the theoretically predicted fidelity for a single-qubit design increases to 99.99%...
Analytical model for the extraction of flaw-induced current interactions for SQUID NDE
, Article IEEE Transactions on Applied Superconductivity ; Volume 21, Issue 4 , 2011 , Pages 3442-3446 ; 10518223 (ISSN) ; Hosseini, M ; Razmkhah, S ; Mehrany, K ; Kokabi, H ; Schubert, J ; Banzet, M ; Krause, H. J ; Fardmanesh, M ; Sharif University of Technology
Abstract
Incorporating an analytical approach to simulate the interaction of a series of long cracks and the induced current of a double-D excitation coil, we have developed a model-based method to do precise detection of the positions of the cracks in a metallic structure by using eddy-current superconducting quantum interference device (SQUID) nondestructive evaluation (NDE) measurements. Conventionally, the structure of the defects is found by iteratively solving a numerical forward problem, which is usually based on finite-element, boundary-element, or volume-integral method. This, however, incurs a heavy numerical burden, as every time the forward problem is to be solved, a rigorous numerical...
An efficient SQUID NDE defect detection approach by using an adaptive finite-element modeling
, Article Journal of Superconductivity and Novel Magnetism ; Volume 24, Issue 1-2 , 2011 , Pages 1077-1081 ; 15571939 (ISSN) ; Razmkhah, S ; Hosseini, N ; Jurgen Schubert ; Banzet, M ; Fardmanesh, M ; Sharif University of Technology
Abstract
Incorporating the finite-element method for the modeling of the SQUID NDE response to a predefined defect pattern, an adaptive algorithm has been developed for the reconstruction of unknown defects using an optimization algorithm for updating of the forward problem. The defect reconstruction algorithm starts with an initial estimation for the defect pattern. Then the forward problem is solved and the obtained field pattern is compared with the measured signal from the SQUID NDE system. The result is used by an optimization algorithm to update the defect structure to be incorporated in the FEM forward problem for the next iteration. Since the mentioned model based inverse algorithm normally...
RF SQUID electronic readout system for the frequency range of 650MHz to 1GHz with automatic parameter setting
, Article Proceedings - 2010 18th Iranian Conference on Electrical Engineering, ICEE 2010, 11 May 2010 through 13 May 2010 ; 2010 , Pages 442-445 ; 9781424467600 (ISBN) ; Razmkhah, S ; Alavi, M. H ; Fardmanesh, M ; Sharif University of Technology
Abstract
A RF SQUID electronic system has been implemented which works at the frequency range of 650MHz to 1GHz. By incorporating particle swarm algorithm for the optimization of the system parameters, the readout system could automatically set its parameters for a desired RF SQUID. Using the implemented system, the noise characteristics of a RF SQUID gradiometer is being measured. The measured flux noise of the High-Tc YBCO magnetometer is below 100μ Φ0/ √ Hz at 100Hz in unshielded environment
Comparison of noise reduction techniques in RF SQUID magnetic detection systems
, Article Proceedings - 2010 18th Iranian Conference on Electrical Engineering, ICEE 2010, 11 May 2010 through 13 May 2010 ; 2010 , Pages 446-449 ; 9781424467600 (ISBN) ; Sarreshtedari, F ; Forooghi, F ; Fardmanesh, M ; Schubert, J ; Banzet, M ; Sharif University of Technology
Abstract
The noise level of the magnetometer and gradiometer RF SQUIDs were investigated using different shielding methods. The used methods include different active and passive shielding, such as Helmholtz configurations, locally compensation coils, superconducting bulks and μ-metal shields. For the passive shielding approach, using FEM simulation we have investigated the shielding effectiveness of superconducting bulks versus the use of μ-metal shielding. The superconducting shield is a YBCO circular bulk, which was made using melt-texture method and located in a distance in front of the SQUID. In this work the results of these shielding methods are presented and compared, while their effectiveness...
An efficient finite-element approach for the modeling of planar double-D excitation coils and flaws in SQUID NDE systems
, Article IEEE Transactions on Applied Superconductivity ; Volume 20, Issue 2 , 2010 , Pages 76-81 ; 10518223 (ISSN) ; Pourhashemi, A ; Asad, N ; Schubert, J ; Banzet, M ; Fardmanesh, M ; Sharif University of Technology
2010
Abstract
Incorporating an efficient approach for the finite-element simulation of eddy current superconductive quantum interface device (SQUID) nondestructive evaluation (NDE) systems, an appropriate finite-element method (FEM) has been presented for simulating and analyzing such systems. We have introduced a new model for the planar double-D coils, which are used as the excitation source in eddy current SQUID NDE systems, and also another model for the description of the flaw effect on the induced current. We have also examined our simulation results with their associated measurements. Our system is based on a high-TC YBCO gradiometer RF-SQUID sensor with a flux noise level below 100 μΦ0 √Hz at 100...
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...
Fabrication of FINEMET bulk alloy from amorphous powders by spark plasma sintering
, Article Powder Technology ; Volume 289 , 2016 , Pages 163-168 ; 00325910 (ISSN) ; Madaah Hosseini, H. R ; Davami, P ; Sarafidis, C ; Sharif University of Technology
Elsevier
Abstract
Finemet bulk soft magnetic alloy was fabricated by spark plasma sintering of the milled ribbons. The amorphous melt-spun ribbons were milled for 36min by high energy vibrational mill and then sieved to separate particles smaller than 125μm. The size distribution of particles was determined by a laser diffraction particle size analyzer. Spark plasma sintering was carried out at super-cooled liquid region for short times of 7 and 21min. The structure of bulk samples was characterized using X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and transmission electron microscopy techniques. The magnetization and coercivity of samples were measured using SQUID...
Influence of material and geometry of the dielectric on the characteristics of the tank circuit resonators for high-Tc RF-SQUID-based system
, Article IEEE Transactions on Applied Superconductivity ; Volume 26, Issue 3 , 2016 ; 10518223 (ISSN) ; Shanehsazzadeh, F ; Sarreshtedari, F ; Fardmanesh, M ; Sharif University of Technology
Abstract
Characteristics of a lumped element L-C tank circuit resonator of high-Tc rf-SQUIDs, which plays an important role in the device operation, have been experimentally investigated, according to the corresponding simulations obtained by COMSOL Multiphysics. We experimentally investigated the characteristics of the resonators by measuring their scattering parameters, as well as evaluating the rf-SQUID signal. Our SQUIDs are made of sputtered YBCO thin films with 3-mm-diameter washer areas. Different configurations of the resonator are investigated, and it is observed that, by increasing the thickness of the dielectric in a specific range, the reflection coefficient (S11) increases. For the...
Low noise active shield for SQUID-Based mag-netocardiography systems
, Article IEEE Transactions on Applied Superconductivity ; 2017 ; 10518223 (ISSN) ; Fardmanesh, M ; Sharif University of Technology
Abstract
light weight and low-cost active magnetic shield sys-tem is proposed for a single channel SQUID-based magnetocardiog-raphy 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 fre-quency 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 corre-lated proportional-integral-derivative closed loop...