Xue Chao, Quan Li-Di, Yang Shan-Qing, Wang Bing-Peng, Wu Jun-Fei, Shao Cheng-Gang, Tu Liang-Cheng, Milyukov Vadim, Luo Jun
MOE Key Laboratory of Fundamental Physical Quantities Measurements, School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
MOE Key Laboratory of Fundamental Physical Quantities Measurements, School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China School of Automation, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
Philos Trans A Math Phys Eng Sci. 2014 Oct 13;372(2026). doi: 10.1098/rsta.2014.0031. Epub 2014 Sep 8.
This paper describes the preliminary measurement of the Newtonian gravitational constant G with the angular acceleration feedback method at HUST. The apparatus has been built, and preliminary measurement performed, to test all aspects of the experimental design, particularly the feedback function, which was recently discussed in detail by Quan et al. The experimental results show that the residual twist angle of the torsion pendulum at the signal frequency introduces 0.4 ppm to the value of G. The relative uncertainty of the angular acceleration of the turntable is approximately 100 ppm, which is mainly limited by the stability of the apparatus. Therefore, the experiment has been modified with three features: (i) the height of the apparatus is reduced almost by half, (ii) the aluminium shelves were replaced with shelves made from ultra-low expansion material and (iii) a perfect compensation of the laboratory-fixed gravitational background will be carried out. With these improvements, the angular acceleration is expected to be determined with an uncertainty of better than 10 ppm, and a reliable value of G with 20 ppm or below will be obtained in the near future.
本文介绍了华中科技大学利用角加速度反馈法对牛顿引力常数G进行的初步测量。实验装置已搭建完成，并进行了初步测量，以测试实验设计的各个方面，特别是反馈功能，Quan等人最近对此进行了详细讨论。实验结果表明，信号频率下扭秤的残余扭转角给G值带来了0.4 ppm的影响。转盘角加速度的相对不确定度约为100 ppm，这主要受装置稳定性的限制。因此，对实验进行了如下三方面改进：（i）装置高度几乎降低了一半；（ii）铝制架子被超低膨胀材料制成的架子所取代；（iii）将对实验室固定引力背景进行完美补偿。通过这些改进，预计角加速度的测量不确定度将优于10 ppm，并且在不久的将来将获得不确定度在20 ppm或更低的可靠的G值。
