Research on Adjustment Method of Distance Between Center of Mass and Optical Center of Falling Body in Absolute Gravimeter
FAN Feng1,YANG Peixi1,WANG Qiyu2,3,FENG Jinyang2,3,YAO Jiamin2,3,HU Ruo2,3,WU Shuqing2,3
1. College of Mathematical Science and Engineering, Hebei University of Engineering, Handan, Hebei 056038, China
2. National Institute of Metrology, Beijing 100029, China
3. Key Laboratory of Time Frequency and Gravity Standard, State Administration for Market Regulation, Beijing 100029, China
Abstract To minimize measurement error of gravity acceleration induced falling body rotation in absolute gravimeter based on laser interferometry, a method for adjusting the distance between center of mass(COM) and the optical center(OC) based on falling body suspension was proposed. Combined with the external structure of falling body, a simple and efficient falling body adjusting device was built. The device adopted photoelectric autocollimator to measure the pitch angle of the falling body in suspension state, which can adjust the position of COM of falling body, and then completed the adjustment of the distance between COM and OC. The uncertainty of the systematic measurement was also evaluated, and the synthetic standard uncertainty of the distance measurement was 18.85μm. Finally, the falling bodies adjusted by suspension method was put into the NIM-3A absolute gravimeter for experimental. The results show that the distance between COM and OC is better than 20μm, which is in line with the estimated uncertainty results. If the angular velocity of the falling body is controlled within 0.02rad/s, the measurement uncertainty of the gravitational acceleration introduced by the falling body rotation is better than 1μGal.
FAN Feng,YANG Peixi,WANG Qiyu, et al. Research on Adjustment Method of Distance Between Center of Mass and Optical Center of Falling Body in Absolute Gravimeter[J]. Acta Metrologica Sinica, 2024, 45(2): 231-237.
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2024, Vol. 45 
