Magnetometer calibration setup controlled by nuclear magnetic resonance

Weyand, K.

doi:10.1109/19.769683

Cited by 13 publications

(6 citation statements)

References 6 publications

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“…NMR is not suitable for measurement in inhomogeneous fields. 8 Hall probes reach high accuracy but give only a local measurement 19 and, moreover, needs for temperature compensation and frequent calibrations. Therefore, the SSW is the most accurate method, 4 although limited by the highorder multipoles.…”

Section: A Calibration Issuesmentioning

confidence: 99%

“…Conversely, microphotogrammetric methods, such as x ray or optical scans, provide high-quality measurements, but are expensive and time consuming. 7,8 Far better results are achieved by calibration in a reference dipole field (stable and uniform), mapped by nuclear magnetic resonance (NMR), 5,9,10 and yielding by definition of the equivalent area very accurately. This area can be measured along the longitudinal axis by means of localized field sources.…”

Section: Introductionmentioning

confidence: 99%

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In situ calibration of rotating sensor coils for magnet testing

Arpaïa

Buzio

Golluccio

et al. 2012

Review of Scientific Instruments

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An in situ procedure for calibrating equivalent magnetic area and rotation radius of rotating coils is proposed for testing accelerator magnets shorter than the measuring coil. The procedure exploits measurements of magnetic field and mechanical displacement inside a reference quadrupole magnet. In a quadrupole field, an offset between the magnet and coil rotation axes gives rise to a dipole component in the field series expansion. The measurements of the focusing strength, the displacement, and the resulting dipole term allow the equivalent area and radius of the coil to be determined analytically. The procedure improves the accuracy of coils with large geometrical irregularities in the winding. This is essential for short magnets where the coil dimensions constrain the measurement accuracy.Experimental results on different coils measuring small-aperture permanent magnets are shown. (2012) Geneva, Switzerland Published in Review of Scientific Instruments CERN-ATS-2012-018 February 2012Abstract REVIEW OF SCIENTIFIC INSTRUMENTS 83, 013306 (2012) In situ calibration of rotating sensor coils for magnet testing An in situ procedure for calibrating equivalent magnetic area and rotation radius of rotating coils is proposed for testing accelerator magnets shorter than the measuring coil. The procedure exploits measurements of magnetic field and mechanical displacement inside a reference quadrupole magnet. In a quadrupole field, an offset between the magnet and coil rotation axes gives rise to a dipole component in the field series expansion. The measurements of the focusing strength, the displacement, and the resulting dipole term allow the equivalent area and radius of the coil to be determined analytically. The procedure improves the accuracy of coils with large geometrical irregularities in the winding. This is essential for short magnets where the coil dimensions constrain the measurement accuracy. Experimental results on different coils measuring small-aperture permanent magnets are shown.

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Section: A Calibration Issuesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In situ calibration of rotating sensor coils for magnet testing

Arpaïa

Buzio

Golluccio

et al. 2012

Review of Scientific Instruments

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“…NMR (nuclear magnetic resonance) is considered the gold standard for high-precision measurements of high-strength magnetic fields [ 1 , 2 , 3 , 4 , 5 , 6 ]. NMR magnetometers are often used to measure magnetic field values, map spatial magnetic field distributions (for example, in the main magnet of the MRI equipment to measure the homogeneity and temperature drift of the main magnetic field) [ 7 , 8 , 9 , 10 , 11 , 12 ], and calibrate magnetic field measurement equipment based on other physical principles [ 13 , 14 ]. However, magnetometers have been limited by the low signal-to-noise ratio (SNR) in low-strength magnetic field conditions, resulting in poor performance in low-strength magnetic field applications.…”

Section: Introductionmentioning

confidence: 99%

NMR Magnetometer Based on Dynamic Nuclear-Polarization for Low-Strength Magnetic Field Measurement

Guo

Wan

et al. 2023

Sensors

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Nuclear magnetic resonance (NMR) magnetometers are considered due to their ability to map magnetic fields with high precision and calibrate other magnetic field measurement devices. However, the low signal-to-noise ratio of low-strength magnetic fields limits the precision when measuring magnetic fields below 40 mT. Therefore, we developed a new NMR magnetometer that combines the dynamic nuclear polarization (DNP) technique with pulsed NMR. The dynamic pre-polarization technique enhances the SNR under a low magnetic field. Pulsed NMR was used in conjunction with DNP to improve measurement accuracy and speed. The efficacy of this approach was validated through simulation and analysis of the measurement process. Next, a complete set of equipment was constructed, and we successfully measured magnetic fields of 30 mT and 8 mT with an accuracy of only 0.5 Hz (11 nT) at 30 mT (0.4 ppm) and 1 Hz (22 nT) at 8mT (3 ppm).

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“…NMR magnetometers are known for their accurate measurement of the homogeneous magnetic field, but the problem at low fields is the lower signal-to-noise ratio which requires the use of larger sample volumes [9][10][11][12][13][14]. Larger sample volumes are not possible because of the tight space available or homogeneity of the 180 • magnet [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

High-precision magnetic field measurement and mapping of the LEReC 180° bending magnet using very low field NMR with Hall combined probe (140−350 G)

Song¹,

Cruz²,

Britt³

et al. 2020

Meas. Sci. Technol.

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The relativistic heavy ion collider (RHIC) at BNL uses low-energy RHIC electron cooling (LEReC) to conduct experiments to search for the quantum chromodynamic critical point. The first ever electron cooling based on the RF acceleration of electron beams was experimentally demonstrated on April 5, 2019 using LEReC at BNL. The first critical step in obtaining successful 3D non-magnetized cooling of the Au ion bunches in the RHIC cooling section was matching the electron beam energy with a relative error less than 5 × 10−4 to the ion beam energy. Part of the LEReC beamline is a dipole magnet that bends the electron beam 180°. One of the most outstanding measurement challenges is that the dipole field is so low (≈200 G). Most of the existing NMR probes can only measure fields >400 G. A lower signal-to-noise ratio at low fields requires the use of larger sample volumes. Working with CAYLAR, the NMR probe has been redesigned and optimized for these low field measurements with high resolution. We report the methods, challenges and results for extensive magnetic field mappings of the 180° dipole magnet. A combination of NMR and Hall sensors was successfully implemented to measure uniform field regimes inside the magnet center area and non-uniform field regimes at the magnet ends. Detailed measurement and mapping were performed at five radii and five heights along the beam trajectory. Meanwhile, a finite element magnetic modeling simulation of the magnet using Opera software was performed. The calculated and measured data were compared, and the calculated data are a good reference for the measured data over long length mapping from the magnet edge to the center. The measured magnetic measurement data are directly useful for beam instrumentation, diagnostics and operation.

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Magnetometer calibration setup controlled by nuclear magnetic resonance

Cited by 13 publications

References 6 publications

In situ calibration of rotating sensor coils for magnet testing

In situ calibration of rotating sensor coils for magnet testing

NMR Magnetometer Based on Dynamic Nuclear-Polarization for Low-Strength Magnetic Field Measurement

High-precision magnetic field measurement and mapping of the LEReC 180° bending magnet using very low field NMR with Hall combined probe (140−350 G)

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