Recent Investigations into the Shape of the Ramsey Resonance Pattern in a Cesium Atomic Clock

The influence of the velocity distribution on the shape of the Ramsey resonance pattern has been investigated both theoretically and experimentally using CSX, the PTB's experimental cesium atomic beam device. It is shown that a distortion ("gaps") in the velocity distribution of the beam atoms may lead to the modulations on the Rabi pedestals which were recently observed in the NRLM-II frequency standard in Japan.