Cold atom gravimeter based on an atomic fountain and a microwave transition

A method based on measuring the shift of Ramsey spectral line in an atomic fountain in the gravitational field has been proposed to develop an atomic gravimeter involving the atomic fountain on ultracold atoms. The accuracy of the measurement of the gravitational acceleration with a fountain microwave frequency standard on Cs atoms is $\delta g= 2\times 10^{-6}g/\sqrt{\tau_a}$. The achievable accuracy at the integration time $\tau_a=10000$ s is $\delta g\approx2\times 10^{-8}g\approx20\,$ $\mu$Gal.