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Q: Fachverband Quantenoptik und Photonik
Q 8: Präzisionsmessungen und Metrologie II
Q 8.1: Vortrag
Montag, 10. März 2008, 16:30–16:45, 3D
The SYRTE’s fountain clocks: towards 10−16 accuracy — •Peter Rosenbusch, Sébastien Bize, Frédéric Chapelet, Jocelyne Guéna, Philippe Laurent, Daniele Rovera, Giorgio Santarelli, and André Clairon — SYRTE, Observatoire de Paris, FRANCE
Today’s best microwave clocks are atomic fountains. About 109 atoms are laser cooled to 1µK and launched up vertically, where they pass, rising and falling, through a microwave cavity. This Ramsey interrogation leads to a 1010 quality factor of the central fringe [S. Bize et al., J. Phys. B vol. 38, S449 (2005)]. The SYRTE disposes of three fountain clocks, one of which uses Cs and Rb, operating quasi-continuously thanks to an interference-filter stabilised laser system [X. Baillard et al., Opt. Comm., vol. 266, 609 (2006)]. The fountains exhibit a relative accuracy of 4× 10−16, making the second the best realised SI unit. Here, we present efforts to further decrease the uncertainty to 10−16. Additionally, measurements of the 87Rb hyperfine transition and their relevance to possible variations of the fine structure constant α are presented.