Pharao: a Cold Atom Clock in μg

Ch Salomon

Philippe Laurent, Michel Abgrall, Ch. Jentsch +17 more

Ch. Delaroche, Ph. Gasc, Andria Ratsimandresy +18 more

PHARAO (Projet d'Horloge Atomique par Refroidissement d'Atomes en Orbite), which has been developed by CNES, is the first primary frequency standard specially designed for operation in space. PHARAO is the main instrument of the ESA mission ACES (Atomic Clock Ensemble in Space). ACES payload will be installed on-board the International Space Station (ISS) to perform fundamental physics experiments. All the sub-systems of the Flight Model (FM) have now passed the qualification process and the whole FM of the cold cesium clock, PHARAO, is being assembled and will undergo extensive tests. The expected performances in space are frequency accuracy less than 3.10-16 (with a final goal at 10-16) and frequency stability of 10-13 τ-1/2. In this paper, we focus on the laser source performances and the main results on the cold atom manipulation.

Steven Peil, J. L. Hanssen, Thomas B. Swanson +2 more

M. Saccoccio, Philippe Laurent, P. Lemonde +5 more

The purpose of the PHARAO project is to develop a new atomic clock generation in space. This clock takes advantage of the very low atomic velocities obtained by laser cooling techniques and the microgravity environment. Designing the PHARAO optical bench, which provides all the laser tools for the atomic manipulations, is a difficult task. In this paper we will give a global overview of the optical bench in term of functions, interfaces and performances. After establishing the optical parameters, which have an impact on the atomic clock performance, we present the model and software, which are used for the design and analysis of the optical system, taking into account the Gaussian laser beams. Some critical functions have been experimented and characterized to prove the model’s accuracy.

吕德胜, 汪斌, 李唐 +1 more