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.