REVIEW OF SCIENTIFIC INSTRUMENTS 87, 034504 (2016)
Research on supporting mounts of spheres in measurement
of gravitational constant G
Qing Li, 1,2 Jian-Ping Liu, 1 Chao Xue, 3 Jun-Fei Wu, 1 Shan-Qing Yang, 1,a) and Jun Luo 1,4,b)
1 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
2 The Department of Electronics and Information Engineering, Huazhong University of Science and Technology,
Wuhan, Hubei 430074, People’s Republic of China
3 School of Physics and Astronomy, Sun Yat-sen University, Guangzhou 510275, People’s Republic of China
4 Sun Yat-sen University, Guangzhou 510275, People’s Republic of China
(Received 9 February 2016; accepted 5 March 2016; published online 18 March 2016)
The ongoing precision measurement of the gravitational constant G at our group is performed by using two different kinds of methods: time-of-swing method (ToS) and angular acceleration feedback method. In the two methods, the stainless steel spheres are employed as source masses, and the position stability of the spheres is an important parameter, which make suitable mounts for supporting the spheres needed extremely. In this paper, an upgraded three-point mount is introduced and tested in detail. Experimental results show that, for the sphere supported by the three-point mount used in the ToS method, the repeatability, the temperature influence, and the vibration influence are all less than 0.1 μm (about 2 ppm for the value of G). For the sphere supported by the three-point mount used in the AAF method, similar results are obtained, the largest change of the sphere’s position is about 0.6 μm, introduced by a temperature change of 1 ◦ C, which also results in an uncertainty of 2 ppm for the value of G. C 2016 AIP Publishing LLC.
