Precision Measurement of Distribution of Film Thickness on Pendulum for Experiment of G

Distribution of film thickness coated on the pendulum of measuring the Newton gravitational constant G is determined with a weighing method by means of a precision mass comparator. The experimental result shows that the gold film on the pendulum will contribute a correction of -24.3ppm to our G measurement with an uncertainty of 4.3ppm, which is significant for improving the G value with high precision.