Plans to improve the experimental limit in the comparison of the east-west and west-east one-way light propagation times on the rotating earth

Abstract

The preceding paper describes the results so far (interrupted in the Spring of 1989 because of lack of funds) of an experiment comparing the one-way light propagation times on the surface of the rotating Earth. For the 20 Km path length component in the East-West direction the predicted difference between the opposite sense propagation times would be 160 ps, if the ≈360 Km/s surface speed of the Earth gives effective light speeds of 3 x 10⁸ m/s ± 360 m/s. This could lead to a prediction of the difference between the clock transport and the light pulse synchronization methods described in the preceding paper: △T = 0.5 (160) = 80 ps. The current upper bound of approximately 100 ps for △T is limited by poorly understood systematic errors. The most important seems to be intensity-dependent time delays in the remote light pulse avalanche photo-diode detector. This will be replaced by a continuously operating circular scan streak camera having single photon sensitivity and a time resolution of ≈5 ps. (This camera has recently been developed by the Xian Institute of Optics and Precision Mechanics in the P.R.C.). Better isolation from shocks and vibration for the Sigma-Tau hydrogen maser during transport will be provided. It is hoped that △T < 20 ps can be achieved.