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Contrôle des collisions froides du césium 133, tests de la variation de la constante de structure fine à l'aide d'une fontaine atomique double rubidium - césium

Abstract : We developed a method of measurement of the frequency shift due to the collisions between cold atoms. This is the main systematic limitation for the accuracy of the 133Cs based fountains (~1E-15 in relative frequency). Consequently, we can measure this effect near 0.5% This opens prospects for improvements of the fountains performances in term of exactitude until 1E-16. The fountain has also obtained a stability about 1E-14 at 1s. We discovered for the first time, at very low magnetic field (5 +/- 1 mG), Feshbach resonances. We also took a new absolute measurement of the hyperfine transition of the 87Rb, which is the most precise ever carried out and is used now as definition for the secondary standard. By comparing this value with those measured the previous years, we could carry out a test of the stability of the fine structure constant on the level of 1E-15/Yr. We led local comparisons between atomic fountains and the other fountains of the laboratory. Most stable it is unrolled with a combined stability of 5E-14 at 1s. The behavior of the difference of the two clocks goes like white frequency noise up to 4E-16. The assessment of the dual fountain accuracy budget has been evaluated at 7E-16 for the cesium part and 8E-16 for the rubidium part. We contributed to the realization of the scale of International Atomic Time, by series of calibrations of hydrogen masers. An atomic comparison of fountain by satellite links was tested between our laboratory and our German counterpart. This measurement has determined the good agreement between the two clocks.
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Contributor : Harold Marion <>
Submitted on : Monday, September 11, 2006 - 2:07:57 PM
Last modification on : Wednesday, September 23, 2020 - 4:37:52 AM
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  • HAL Id : tel-00008921, version 3

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Harold Marion. Contrôle des collisions froides du césium 133, tests de la variation de la constante de structure fine à l'aide d'une fontaine atomique double rubidium - césium. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2005. Français. ⟨tel-00008921v3⟩

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