Progress in the development of a spherical superconducting gravimeter based on SQUID detection

Area of Science:

• Geophysics
• Quantum Metrology

Background:

• Traditional gravimeters face limitations in sensitivity and noise.
• Superconducting Quantum Interference Devices (SQUIDs) offer potential for enhanced precision measurements.

Purpose of the Study:

• To design and develop a spherical superconducting gravimeter with ultrahigh sensitivity.
• To achieve lower noise levels in gravity measurements using SQUID detection.
• To validate the prototype's performance through solid tide observations.

Main Methods:

• Development of a novel multi-coil levitation system to enhance low-frequency sensitivity and noise suppression.
• Comprehensive noise analysis including mechanical thermal noise and SQUID noise.
• Solid tide observation experiment over five days with linear fitting analysis against GWR tidal data.

Main Results:

• Theoretical noise level below the New Low Noise Model (NLNM) across the frequency spectrum.
• Achieved transfer function of 55.974 ± 0.053 μGal/V, exceeding design expectations.
• Experimental solid tide data showed excellent agreement with theoretical predictions.

Conclusions:

• The developed superconducting gravimeter prototype confirms the feasibility of the design.
• The novel levitation system effectively enhances sensitivity and noise suppression.
• The results validate the theoretical model and demonstrate potential for advanced gravity measurements.