Measurement of the Frequency-Shift Due to Distributed Cavity Phase Difference in an Atomic Clock

The Ramsey cavity of a Cs beam frequency standard was moved vertically and horizontally perpendicular to the beam axis. In the vertical direction the measured frequency of the clock transition depends linearly upon the place of irradiation due to a change in the cavity phase difference. Simplified assumptions are made in the computation of the distributed phase. Experimental and theoretical results agree satisfactorily.