scholarly journals Using Proton Nuclear Magnetic Resonance (NMR) as a calibrating reference for magnetic field measurement instruments: Sensitive volume and magnetic field homogeneity

Measurement ◽  
2020 ◽  
Vol 151 ◽  
pp. 107228 ◽  
Author(s):  
Gonzalo G. Rodriguez ◽  
Guillermo Forte ◽  
Esteban Anoardo
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Field Measurement ◽  
Proton Nuclear Magnetic Resonance ◽  
Magnetic Field Measurement ◽  
Sensitive Volume ◽  
Measurement Instruments ◽  
Magnetic Field Homogeneity ◽  
Field Homogeneity

scholarly journals LADRC-Based Magnetic Field Measurement Method for a Nuclear Magnetic Resonance Rotation Sensor

2021 ◽  
Vol 11 (21) ◽  
pp. 10458
Author(s):  
Xinghua Zhao ◽  
Zhanchao Liu ◽  
Xinda Song ◽  
Jianli Li ◽  
Yibo Shao
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Field Measurement ◽  
Magnetic Field Measurement ◽  
Loop Control ◽  
Rotation Sensor ◽  
Resonance Rotation ◽  
Phase Loop ◽  
Nuclear Magnetic

Magnetic field measurement is fundamental to nuclear magnetic resonance rotation sensors (NMRRS). A phase-locked loop (PLL)-based measurement with two nuclear isotopes is commonly applied to observe the magnetic field. However, the phase-loop and frequency-loop of the nuclear isotopes cannot be optimized simultaneously by a PLL-based method. In this paper, an approach based on a linear active disturbance rejection controller (LADRC) is proposed for synchronous phase-loop control of the two nuclear isotopes. Meanwhile, the frequencies of the nuclear isotopes are observed by linear extended state observers (LESOs). The phase and frequency loops can be decoupled and optimized with the proposed method. An experimental NMRRS prototype used for verification is built. The effectiveness and the feasibility of the proposed method are validated with the experimental results.

Diamagnetization in the Vortex State of Bi(Pb)-Sr-Ca-Cu-O: Magnetic Field Measurement at the Surface by Nuclear Magnetic Resonance

1991 ◽  
Vol 30 (Part 2, No. 4A) ◽  
pp. L572-L575 ◽  
Author(s):  
Yutaka Maniwa ◽  
Hiroshi Sato ◽  
Taku Mituhashi ◽  
Kenji Mizoguchi ◽  
Ikuyo Shiozaki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Field Measurement ◽  
Vortex State ◽  
Magnetic Field Measurement ◽  
Nuclear Magnetic

scholarly journals The development of the magnetic system of sensor for PMR-analyser

2020 ◽  
Vol 22 (4) ◽  
pp. 115-122
Author(s):  
A. Y. Svinin ◽  
R. S. Каshaev ◽  
O. V. Коzelkov
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic System ◽  
Scientific Paper ◽  
Magnetic Sensors ◽  
Measuring Instruments ◽  
Main Task ◽  
Magnetic Field Homogeneity ◽  
Nuclear Magnetic

The enhancement of the measuring instruments accuracy has always been the most crucial task for engineers and scientists. In particular, in the field of nuclear magnetic resonance, the creation of uniform magnetic field often defines the results of measurements, therefore the main task of this study is to develop Halbach magnet array based on design characteristics of developing NMR-analyzer. The research describes the development process of the main sensor’s magnetic system components for continuous-flow portable NMR-analyzer. The scientific paper makes a different variations analysis of Halbach magnet arrays on the degree of the magnetic field homogeneity, shows the process of development and production of the 3D-framework for Halbach magnet array for NMR-analyzer. The article also gives information on the design of quartz generator based on Pierce oscillator circuit for receiver-transmitter coil of the NMR-analyzer’s sensor. The results could be useful for the magnetic sensors design with high degree of homogeneity, measuring instruments and devices using the method of nuclear magnetic resonance in its foundation.

Comparative study of helical-cut notch–coil magnets for fast-field-cycling nuclear magnetic resonance

2014 ◽  
Vol 92 (11) ◽  
pp. 1430-1440 ◽  
Author(s):  
S. Kruber ◽  
G.D. Farrher ◽  
E. Anoardo
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnet System ◽  
Fast Switching ◽  
Magnetic Field Homogeneity ◽  
Field Cycling ◽  
Fast Field ◽  
The Magnetic Field ◽  
Nuclear Magnetic

In this manuscript we describe an α-helical-cut notch–coil magnet system designed for fast switching of the magnetic field. An attempt was made to determine the extent to which such a magnet configuration can be efficiently used for fast-field-cycling (FFC) nuclear magnetic resonance (NMR) instruments. In addition to the typical technical requirements (high field-to-power ratio, adequate electric performance for fast-switching of the magnetic field and NMR-compatible magnetic field homogeneity), a tunable homogeneity within the sample volume and more uniform heat dissipation along the magnet body are included. A helical-cut notch–coil machined in metallic cylinders with external movable pieces was found to fit these requirements very well. A key factor for the optimization of the magnet parameters is the use of a novel calculation procedure based on a more realistic model that consider a magnet geometry with broken azimuthal symmetry. The aim of this paper is to theoretically compare the proposed geometry with other existing designs. No particular prototype is presented here. A clear understanding of the notch–coil performance was found to be an essential step for its further consideration as a potential autoadaptive (electronically controlled) magnet system for FFC applications.

scholarly journals Design and Testing of Radiofrequency Spherical four Coils

2016 ◽  
Vol 10 (5) ◽  
pp. 186 ◽  
Author(s):  
Sidi Mohamed Ahmed Ghaly ◽  
Khalid. A. Al-snaie ◽  
Sulaiman S. Al-Sowayan
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
Spherical Surface ◽  
Resonance Imaging ◽  
Rf Systems ◽  
Magnetic Field Homogeneity ◽  
Field Homogeneity ◽  
B1 Field ◽  
Design And Testing

<p>In this paper, we present the design and testing of a radiofrequency prototype coil with good performances in terms of B<sub>1</sub> magnetic field homogeneity and can be utilized for Magnetic Resonance Imaging. It is constituted of four coaxial separately tuned rings of wire and symmetrically located on a spherical surface. Compared to standard Helmholtz pair, which has 2nd-order magnetic field homogeneity, it yields to improvement in field homogeneity, while preserving the simplicity of design. The four coils of proposed structure are tuned to the same frequency. The proposed structure gets at 4th-order magnetic field homogeneity by optimizing the distance between rings and the diameters of outer loops. An electrical modeling of the four-coil system taking into account the coupling effects between all rings permits to determine the resonance frequency in the homogenous mode. Measurements of B1 field homogeneity were introduced in free space. Compared to the Helmholtz coil, the proposed structure presents good performances in terms of B1 homogeneity, quality factor and sensitivity. The design of proposed coil has been optimized for best SNR performances. Globally, this work claims to be a contribution to the study of the four-coil RF systems derived from the Helmholtz pairs.</p>

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