Wide-Band Vertical Superconducting Accelerometer for Simultaneous Observations of Temporal Gravity and Ambient Seismic Noise

Ma, Dong; Liu, Xikai; Zhang, Mao; Zhang, Ning; Chen, Liang

doi:10.1103/physrevapplied.12.044050

Cited by 12 publications

(6 citation statements)

References 22 publications

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“…SQUIDs are ultra-high sensitive devices integrated by the Josephson junctions and the read-out circuits [ 20 ], the sensitivity of SQUIDs is at the level of μΦ 0 /Hz 1/2 , where 1 Φ 0 = 2.06 × 10 −15 Wb. As a benefit of the SQUIDs, the sensitivity of the FM-VSA can be lower than 10 −9 g/Hz 1/2 [ 9 ].…”

Section: Theoretical Analysismentioning

confidence: 99%

“…λ 1 , λ 2 , λ 3 , and λ 4 are the four coefficients of each coil related to the displacement. Then, according to the conservation of magnetic flux of the superconducting circuits [ 9 ]:

…”

Section: Theoretical Analysismentioning

confidence: 99%

“…Due to benefits such as low drift and high sensitivity [ 1 , 2 , 3 ], these instruments have a broad range of applications in geodynamic studies, natural disaster monitoring, and resource exploration [ 4 , 5 , 6 , 7 ]. In FM-VSGIs, superconducting levitating coils are used to levitate the test mass in the sensitive axis (the vertical direction), and side-wall superconducting coils are used to provide the needed stiffness to limit the motion of the test mass in the non-sensitive axes (the horizontal direction) [ 8 , 9 ]. The motion of the test mass has multiple degrees of freedom.…”

Section: Introductionmentioning

confidence: 99%

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Method for Translation and Rotation Decoupling of Test Mass in Full-Maglev Vertical Superconducting Gravity Instruments

Wang

Chen

Liu

et al. 2020

Sensors

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For full-maglev vertical superconducting gravity instruments, displacement control in the non-sensitive axis is a key technique to suppress cross-coupling noise in a dynamic environment. Motion decoupling of the test mass is crucial for the control design. In practice, when levitated, the test mass is always in tilt, and unknown parameters will be introduced to the scale factors of displacement detection, which makes motion decoupling work extremely difficult. This paper proposes a method for decoupling the translation and rotation of the test mass in the non-sensitive axis for full-maglev vertical superconducting gravity instruments. In the method, superconducting circuits at low temperature and adjustable gain amplifiers at room temperature are combined to measure the difference between the scale factors caused by the tilt of the test mass. With the measured difference of the scale factors, the translation and rotation are decoupled according to the theoretical model. This method was verified with a test of a home-made full-maglev vertical superconducting accelerometer in which the translation and rotation were decoupled.

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Section: Theoretical Analysismentioning

confidence: 99%

“…λ 1 , λ 2 , λ 3 , and λ 4 are the four coefficients of each coil related to the displacement. Then, according to the conservation of magnetic flux of the superconducting circuits [ 9 ]:

…”

Section: Theoretical Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Method for Translation and Rotation Decoupling of Test Mass in Full-Maglev Vertical Superconducting Gravity Instruments

Wang

Chen

Liu

et al. 2020

Sensors

Self Cite

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“…Compared with China's establishment of multi-physical field observation networks only in land areas and certain other key areas (Ye et al, 2010), developed countries such as Japan and the United States, as well as the European Union, have established relatively complete joint observation networks in ocean and land areas and carried out underground and deep underground multi-physical field observations. For example, as superconducting gravimeters have extremely low instrument noise and require an ultraquiet environment (Ma D et al, 2019), the Membach Laboratory in Belgium (40 m underground), the Walferdange underground laboratory in Luxembourg (80 m underground), the Kamioka underground laboratory in Kamioka, Japan (the inner cavity of a mountain, covered approximately 1000 m), and the LSBB underground laboratory in France (covered approximately 550 m) have carried out surface and deep underground experiments to perform high-precision superconducting gravity and geomagnetic observations (Waysand et al, 2009). The observation quality of the superconducting gravimeter in the French LSBB laboratory exceeds that of the most accurate stations in the world, showing that the deep subsurface environment has a very low level of noise (Rosat et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Observation and research of deep underground multi-physical fields—Huainan −848 m deep experiment

Wang

Yang

Sun

et al. 2022

Sci. China Earth Sci.

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Compared with the surface, the deep environment has the advantages of allowing “super-quiet and ultra-clean”-geophysical field observation with low vibration noise and little electromagnetic interference, which are conducive to therealization of long-term and high-precision observation of multi-physical fields, thus enabling the solution of a series of geoscience problems. In the Panyidong Coal Mine, where there are extensive underground tunnels at the depth of 848 m belowsea level, we carried out the first deep-underground geophysical observations, including radioactivity, gravity, magnetic, magne-totelluric, background vibration and six-component seismic observations. We concluded from these measurements that (1) the background of deep subsurface gravity noise in the long-period frequency band less than 2 Hz is nearly two orders ofmagnitude weaker than that in the surface observation environment; (2) the underground electric field is obviously weaker thanthe surface electric field, and the relatively high frequency of the underground field, greater than 1 Hz, is more than two orders of magnitude weaker than that of the surface electric field; the east-west magnetic field underground is approximately the same asthat at the surface; the relatively high-frequency north-south magnetic field underground, below 10 Hz, is at least one order ofmagnitude lower than that at the surface, showing that the underground has a clean electromagnetic environment; (3) in additionto the high-frequency and single-frequency noises introduced by underground human activities, the deep underground spacehas a sig-nificantly lower background vibration noise than the surface, which is very beneficial to the detection of weakearthquake and gravity signals; and (4) the underground roadway support system built with ferromagnetic material interferesthe geomagnetic field. We also found that for deep observation in the “ultra-quiet and ultra-clean” environment, the existinggeophysical equipment and observation technology have problems of poor adaptability and insufficient precision as well asdata cleaning problems, such as the effective separation of the signal and noise of deep observation data. It is also urgent tointerpret and comprehensively utilize these high-precision multi-physics observation data.

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“…In addition to the high measurement accuracy, good operating stability and long service life, superconducting gravimeters also have an extremely low noise and drift rate (Goodkind, 1999); to some extent, it solves a series of problems in conventional spring gravimeters. Teams from different countries are also developing superconducting gravity gradiometers (Griggs et al , 2017; Ma et al , 2019; Paik and Lumley, 1996), which are based on the same superconducting magnetic levitation principle as that of superconducting gravimeters.…”

Section: Introductionmentioning

confidence: 99%

Study on room-temperature effect of a superconducting gravimeter prototype

Xing

Niu

et al. 2022

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Purpose This study aims to reveal the room-temperature effect of a superconducting gravimeter prototype, which will guide its subsequent optimization to improve its gravimetric measurement accuracy. Design/methodology/approach Without leveling, the prototype output signal, tilt data and room temperature were measured under steady operating conditions. After analyzing the correlations of the three data sets, the residuals of the prototype’s output signal were compensated using the tilt data and the geodynamic effects (ocean tide loading, atmospheric loading and the gravitational effect of polar motion) were then corrected. Findings The remaining residuals after correction may be caused by small tilt variations that are due to the sensor chamber temperature and radiation shield temperature changes. These small tilt variations were submerged in the tilt signal noise. Although the peak-to-peak noise of the tiltmeter does not exceed 15 µrad, it can still produce gravimetric deviations above 60 µGal when the prototype is significantly tilted. Originality/value This study analyzes in detail the room-temperature effect of a superconducting gravimeter prototype, introduces the tilt effect of the relative gravimeters to compensate for the gravimetric deviations and emphasizes that the improvement of fine leveling and the accuracy of the tiltmeter are key requirements for the prototype to perform high-accuracy gravity measurement tasks.

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Wide-Band Vertical Superconducting Accelerometer for Simultaneous Observations of Temporal Gravity and Ambient Seismic Noise

Cited by 12 publications

References 22 publications

Method for Translation and Rotation Decoupling of Test Mass in Full-Maglev Vertical Superconducting Gravity Instruments

Method for Translation and Rotation Decoupling of Test Mass in Full-Maglev Vertical Superconducting Gravity Instruments

Observation and research of deep underground multi-physical fields—Huainan −848 m deep experiment

Study on room-temperature effect of a superconducting gravimeter prototype

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