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Thomann, Pierre

Nom
Thomann, Pierre
Affiliation principale
Fonction
Professeur honoraire
Email
pierre.thomann@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/481

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  • Publication
    Métadonnées seulement
    Bright, slow, and continuous beam of laser-cooled cesium atoms
    (1999)
    Berthoud, Patrick
    ;
    Fretel, Emmanuel
    ;
    Thomann, Pierre 
    By the moving molasses technique we have extracted laser-cooled cesium atoms in a continuous way directly from an optical molasses. The mean launching velocity is precisely tunable from 1 to 12 m/s. The atomic beam has a flux of 1.3 x 10(8) atom/s at 7 m/s and a longitudinal temperature of 70 mu K; which represents the highest flux and lowest velocity spread obtained so far in a continuous beam of cold atoms. These features makes it well suited for atomic fountains. The atomic flux can be slightly increased in a two-dimensional magneto-optical trap operation (+40%). A simple model accounts for the observed dependence of the flux with the magnetic-field gradient. [S1050-2947(99)51212-2].
  • Publication
    Métadonnées seulement
    An alternative cold cesium frequency standard: The continuous fountain
    (: Ieee-Inst Electrical Electronics Engineers Inc, 1999)
    Dudle, Gregor
    ;
    Mileti, Gaetano 
    ;
    Joyet, Alain 
    ;
    Fretel, Emmanuel
    ;
    Berthoud, Patrick
    ;
    Thomann, Pierre 
    We report on the primary frequency standard now under construction at the Observatoire de Neuchatel (ON). The design is based on a continuous fountain of laser-cooled cesium atoms, which combines two advantages: the negligible contribution of collisions to the inaccuracy and the absence of stability degradation caused by aliasing effects encountered in pulsed operation. The design is reviewed with special emphasis on the specific features of a continuous fountain, namely the source, the microwave cavity (TE021 mode), and the microwave modulation scheme, The possible sources of frequency biases and their expected contributions to the error budget are discussed. Based on present data, an accuracy in the low 10(-15) range and a short-term stability of 7 . 10(-14) are attainable simultaneously under the same operating conditions.