Gravimetry platform for evaluation and characterization of quantum technologies

The Horizon Europe project “Qu-Test” [1] aims to establish a European infrastructure open to industry for the characterization and testing of components, subsystems, and instruments developed from quantum technologies. As part of this project, led by a consortium of Research Technology Institutes and National Metrology Institutes within the European Union, we are developing a platform for the functional and metrological characterization of quantum gravimeters.

In my poster, I will present our reference site, which comprises our laboratory, characterized instruments, and models derived from 20 years of measurements.

Our laboratory, located in the Paris region, features a 6 m × 5.5 m × 2 m concrete platform supported by 12 m long legs that reach the Fontainebleau sands layer. Initially constructed for the LNE Watt Balance [2], our activities have since expanded to include the use, study, characterization, and calibration of various types of instruments. Relative spring-based gravimeters, such as portable Scintrex CG5 and CG6 models, enable us to map and model gravity differences throughout the laboratory's 40 m³ volume. A superconducting relative gravimeter iGrav, allows continuous monitoring of temporal changes of g. The absolute reference value is provided by the atomic gravimeter CAG [3], which calibrates the iGrav’s scale factor [4] and evaluates its drift.

The laboratory's size facilitates the simultaneous accommodation of several gravimeters, enabling regular comparison campaigns. The first comparison in 2006 involved only absolute gravimeters of the FG5 type, while recent comparisons have also included atomic gravimeters like AQGs [5]. The site is routinely used to assess the performance and verify the functionality of the French national gravimeter park (PIN PGravi) [6], particularly before participating in international comparisons with FG5 (#206 and #228) [7] and AQG-B01 [8].

This open-access reference site allows users to verify their instruments before field missions, calibrate spring-based relative gravimeters such as the gPhoneX, and test new developments, including quantum gravimeter and dual gravi-gradio-meter systems.

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

[2] M. Thomas et al (2017) metrologia 54

[3] R. Karcher et al (2018) New J. Phys 20

[4] S. Merlet et al (2021) J Geod 95

[5] V. Ménoret et al (2018) Sci Rep 8

[6] S. Merlet et al (2024) IEEE Instrum Meas Mag 27

[7] H. Wziontek et al (2025) G4.2 EGU

[8] S. Merlet et al (2025) G4.2 EGU