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.

In 10 years of production, more than 20 units have since been produced for various geophysical applications, including hydrology and volcanology. We present here an overview on the results obtained over this large panel of instruments. Comparison of the sensitivity of the instruments at our premises prior to shipping, shows reproducible performance in the range of 600-800 nm/s²/sqrt(Tau), reaching a stability better than 10 nm/s² after approximately one hour of integration.

Ongoing work focuses on two main axes: the completion and improvement of a budget of systematic effects, that is necessary to evaluate the trueness of the instruments, several instruments already delivered with such a budget; and the improvement of remote operability with the development of a self-leveling tripod.

[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.