Application of Ultra-Low Field HTS-SQUID NMR/MRI to Contaminant Detection in Food

Hatsukade, Yoshimi; Abe, Takayuki; Tsunaki, Shingo; Yamamoto, Masaaki; Murata, Hayaki; Tanaka, Saburo

doi:10.1109/tasc.2012.2237473

Cited by 16 publications

(4 citation statements)

References 9 publications

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“…The Bp-pulse has to be much stronger than B0; therefore, the intensities of the Bp-pulse in previous studies were more than 10 mT (sometimes over 100 mT). Even though the protection techniques for SQUID sensors have been proposed and included in the developed ULF-MRI systems 7), 9), 10), 17), 18) , some difficulties still arise for their practical applications, such as increase in the measurement time due to applying the Bp-pulse, difficulty in avoiding the eddy current in the metal material such as electromagnetic shields, and increasing the equipment scale to generate the Bp-pulse.…”

Section: Introductionmentioning

confidence: 99%

Development of Ultra-Low Field Magnetic Resonance Imaging System at 1 mT

et al. 2023

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Ultra-low field (ULF) magnetic resonance imaging (MRI) is considered an innovative MRI technique that can be combined with magnetoencephalography (MEG). In this study, a 1-mT ULF-MRI system without a pre-polarization technique aiming at combining an MEG system is developed. The intensity of the static magnetic field B0 is decided considered to be 1 mT because of the limitation of the magnetic field exposed to our MEG sensor made of superconducting quantum interference devices (SQUIDs). A square-shaped (750 mm × 750 mm) B0-coil based on a Merritt-type configuration is fabricated. The inhomogeneity of B0 is less than 0.07 % in the ±125 mm area. Further, an induction coil is employed to detect the magnetic resonance signal instead of the SQUID sensors of the MEG to confirm the feasibility of realizing MRI measurement at 1 mT without the pre-polarization technique. Relaxation time measurements and MR imaging of a phantom made of a CuSO4 aqueous solution are performed. Reasonable longitudinal and transverse relaxation times are obtained, and clear shapes of the phantom are obtained using the gradient-and spin-echo pulse sequences with this ULF-MRI system. These results indicate the potential of the proposed 1-mT ULF-MRI to effectively integrate ULF-MRI and MEG systems without pre-polarization.

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Section: Introductionmentioning

confidence: 99%

Development of Ultra-Low Field Magnetic Resonance Imaging System at 1 mT

et al. 2023

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“…It is widely used in numerous applications including space exploration, national defense construction, geological and mineral resources survey, medical equipment, etc., due to its easy operation and high stability [1,2]. The research on the weak magnetic measurement instrument with both high precision and high sensitivity has a wide range of applications and important significance in the instrument development [3,4]. The improved proton magnetometer is based on the principle of Overhauser effect, further reducing the power consumption [5,6], and improving the accuracy and sensitivity [7,8].…”

Section: Introductionmentioning

confidence: 99%

Construction of an Overhauser magnetic gradiometer and the applications in geomagnetic observation and ferromagnetic target localization

Liu

et al. 2017

J. Inst.

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The proton precession magnetometer with single sensor is commonly used in geomagnetic observation and magnetic anomaly detection. Due to technological limitations, the measurement accuracy is restricted by several factors such as the sensor performance, frequency measurement precision, instability of polarization module, etc. Aimed to improve the anti-interference ability, an Overhauser magnetic gradiometer with dual sensor structure was designed. An alternative design of a geomagnetic sensor with differential dual-coil structure was presented. A multi-channel frequency measurement algorithm was proposed to increase the measurement accuracy. A silicon oscillator was adopted to resolve the instability of polarization system. This paper briefly discusses the design and development of the gradiometer and compares the data recorded by this instrument with a commonly used commercially Overhauser magnetometer in the world market. The proposed gradiometer records the earth magnetic field in 24 hours with measurement accuracy of ± 0.3 nT and a sampling rate of 3 seconds per sample. The quality of data recorded is excellent and consistent with the commercial instrument. In addition, experiments of ferromagnetic target localization were conducted. This gradiometer shows a strong ability in magnetic anomaly detection and localization.To sum up, it has the advantages of convenient operation, high precision, strong anti-interference, etc., which proves the effectiveness of the dual sensor structure Overhauser magnetic gradiometer. K: Manufacturing; Detector design and construction technologies and materials; Instrument optimisation; Space instrumentation 1Corresponding author.

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“…These types of magnetometers have the advantages of high accuracy, high sensitivity, etc. They are widely used in space exploration [5], near-surface exploration [6], ocean exploration [7], measurement of the Earth's magnetic field [8], military technology [9] and more [10,11].…”

Section: Introductionmentioning

confidence: 99%

Research on a secondary tuning algorithm based on SVD & STFT for FID signal

Huan¹,

Dong²,

Ge³

et al. 2016

Meas. Sci. Technol.

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The tuning precision of a Proton precession magnetometer’s sensor is the key to getting the best signal to noise ratio (SNR) of free induction decay (FID) signals. By analyzing the noises of the magnetometer’s sensor and conditioning circuit, this paper introduces the principle of tuning and proposes a secondary tuning algorithm based on the singular value decomposition (SVD) and short-time Fourier transform (STFT), targeting the current lack of a tuning method. Moreover, the STFT for an FID signal’s feature analysis is applied for the first time. First, the space matrix is constructed by the acquisition of ADC for the untuned FID signal, and then the SVD is performed to eliminate the noise and obtain the useful signal. Finally, the STFT technique is applied to the denoised signal to extract the time-frequency feature. By theory analysis, simulation modeling and the testing of an actual FID signal, the results show that, compared with general tuning methods such as peak detection and fast Fourier transform (FFT), the proposed algorithm improves the sensor’s tuning precision, and the time of the tuning process is no more than one second. Furthermore, the problem of mistuning in strong-disturbance environments is solved. Thus, the secondary tuning algorithm based on the SVD and STFT is more practical.

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Application of Ultra-Low Field HTS-SQUID NMR/MRI to Contaminant Detection in Food

Cited by 16 publications

References 9 publications

Development of Ultra-Low Field Magnetic Resonance Imaging System at 1 mT

Development of Ultra-Low Field Magnetic Resonance Imaging System at 1 mT

Construction of an Overhauser magnetic gradiometer and the applications in geomagnetic observation and ferromagnetic target localization

Research on a secondary tuning algorithm based on SVD & STFT for FID signal

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