Improving performances of LNE-OP/LTE Cold Atom Gravimeter

Atom gravimeters based on atom interferometry offer measurement capabilities, by combining high sensitivities and accuracies at the best level of a few tens of nm s⁻² with the possibility to perform continuous measurements. Being absolute meters, their scale factor is accurately determined and do not need calibration.

We have developed a laboratory state-of-the-art cold atom gravimeter (CAG). The measurement is based on atomic interferometry techniques using stimulated Raman transitions on free-falling 87Rb atoms. The phase shift of the atomic interferometer is proportional to g, the acceleration due to gravity, which we measure with a sensitivity greater than that of conventional absolute gravimeters (5.7ng/rac(Hz)) and with greater accuracy (2ng).

The instrument being movable, participated to international comparisons since 2009 and became the French reference standard. Its limitations have been identified and several improvements are ongoing to achieve the 10^-10 range in terms of accuracy and stability. It will then come back to the reference gravimetric station at LNE, the French National Metrological Institute. These activities take part the European Qu-Test project [1] and of MetriQs-France platform [2].

The poster will present the instrument and improvements and next steps from tests and metrology characterization to its involvement in the European project EQUIP-G [3] as it will participate to the project final comparison in 2028.

 

Qu-Test project is funded by the European Commission under the Horizon Europe program, grant number 101112931

EQUIP-G project is funded by the European Commission under the Horizon Europe program, grant number 101215427

 

[1] https://qu-test.eu

[2] https://www.lne.fr/fr/metriqs-france/plateforme-hub

[3] https://www.equip-g.eu