A space clock prototype using cold cesium atoms

We describe a compact cold atom cesium frequency standard designed as a prototype of a space device. On earth, the experimental resonance linewidth is 13 Hz with a preliminary signal to noise ratio around 300. This prototype has been successfully tested in the reduced gravity of aircraft parabolic flights. A preliminary resonance fringe of 7 Hz linewidth has been obtained. The main advantages of this clock are transportability and reliability. This is a major step toward a space clock using cold atoms. Minor changes would optimize its performances in presence of gravity and lead to performances comparable to those of the BNM-LPTF atomic fountain. It would be an ideal tool for comparison of distant ground based clocks.