Absolute Quantum Gravimeter for Field Applications

Absolute gravity measurements at the level of 1 µGal using cold atom quantum technology have been demonstrated in the laboratory in 1992 and have ever since received an increasing interest from the geophysics community [1]. In 2015, Exail launched on the marketplace the Absolute Quantum Gravimeter (AQG) [2]. Cutting-edge technology developments brought the necessary easy-of-use, autonomy, and robustness for field deployment. More than 15 units have since been produced for various geophysical applications, including hydrology and volcanology. Designed for field applications with autonomous or remote-controlled operation, the AQG does not require heavy vibration isolation equipment thanks to an integrated real time vibration compensation module which hybridizes the quantum measurement with a built-in classical accelerometer. As a result, all units reproducibly achieve a resolution of 10-9 g after < 2 hours of measurement at our inner-city factory site or after < 40 minutes at a quiet site, as we will demonstrate in this talk [2,4]. Moreover, we will present recent progress on the AQG including a gravity measurement campaign that has been on-going for 3 years now near the summit of Mt Etna [3,4]. Finally, we will detail our study of systematic effects affecting the instrument, whose evaluation is required to build a rigorous accuracy (or trueness) budget. [1] M. Kasevich, S. Chu. Measurement of the gravitational acceleration of an atom with a light-pulse atom interferometer. Applied Physics B, 1992, vol. 54, p. 321-332.[2] V. Ménoret et al, Gravity measurements below 10-9 g with a transportable absolute quantum gravimeter. Scientific Reports, 2018, 8, pp.12300.[3] L. Antoni-Micollier et al Detecting volcano-related underground mass changes with a quantum gravimeter. Geophysical Research Letters, vol. 49, issue 13, e2022GL097814 (2022).[4] L. Antoni-Micollier et al, Absolute quantum gravimeters and gradiometers for field measurements. IEEE Instrumentation & Measurement Magazine (submitted).