A Laser-Interferometer System for the Absolute Determination of the Acceleration of Gravity

摘要

A new and portable instrument for making an absolute determination of the acceleration of gravity has been built. The design and construction of this apparatus together with the results obtained using it are discussed. The instrument consists of an optical interferometer in which one of the mirrors, a corner cube reflector, freely falls. The resulting fringes are counted to provide a direct measurement of the distance fallen in terms of the wavelength of light. A stabilized He-Ne laser is used for the light source and provides the required coherence and brightness to achieve high quality fringes over the one meter dropping distance. The drop-to-drop scatter is less than 1 part in 10,000,000, and the consistency of 50 drop data sets each is better than plus or minus 3 parts in 10 to the 8th power. Non-gravity forces and other experimental factors have been carefully taken into account; the accuracy of the final results (70% confidence level) is plus or minus 5 parts in 10 to the 8th power. Measurements have been made at and results are given. (Author) These are the National Bureau of Standard