Preliminary determination of Newtonian gravitational constant with angular acceleration feedback method
Chao Xue1, Li-Di Quan2, Shan-Qing Yang1
1MOE Key Laboratory of Fundamental Physical Quantities Measurements, School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
Summary
Researchers measured the Newtonian gravitational constant (G) using angular acceleration feedback. Initial results show a 0.4 ppm twist angle impact, with apparatus stability limiting precision to 100 ppm.
Area of Science:
- Physics
- Metrology
Background:
- Accurate measurement of the Newtonian gravitational constant (G) is fundamental to physics.
- Previous methods have limitations in precision and stability.
- The angular acceleration feedback method offers a novel approach to G determination.
Purpose of the Study:
- To perform preliminary measurements of G using the angular acceleration feedback method.
- To evaluate the performance of the experimental apparatus and identify sources of uncertainty.
- To refine the experimental design for improved accuracy.
Main Methods:
- Utilized an angular acceleration feedback method for measuring G.
- Constructed and tested a torsion pendulum apparatus.
- Analyzed the impact of residual twist angle on G measurements.
Main Results:
- Preliminary measurements indicate a 0.4 ppm contribution to G from the residual twist angle.
- The relative uncertainty in angular acceleration was approximately 100 ppm, primarily due to apparatus instability.
- Identified key areas for experimental improvement.
Conclusions:
- The experimental design, particularly the feedback function, was validated.
- Modifications including reduced height, improved materials, and background compensation are implemented.
- Future measurements aim for an angular acceleration uncertainty below 10 ppm and a G value with <20 ppm uncertainty.
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