First evaluation of an absolute quantum gravimeter (AQG#B01) for future field experiments

Quantum gravimeters are a promising new development allowing for continuous absolute gravity monitoring while
remaining user-friendly and transportable. In this study, we present experiments carried out to assess the capacity of the
AQG#B01 in view of future deployment as a field gravimeter for hydro-geophysical applications. The AQG#B01 is the field
version follow-up of the AQG#A01 portable absolute quantum gravimeter developed by the French quantum sensor company
Muquans. We assess the instrument’s performance in terms of stability (absence of instrumental drift), sensitivity in relation to
other gravimeters. Furthermore, the measurements allowed for the successful monitoring of a hydrological mass change. We
discuss the observations concerning the accuracy of the AQG#B01 in comparison with a state-of-the-art absolute gravimeter
(Micro-g-LaCoste, FG5#228). Repeatability is tested by instrument displacement between close-by measurement positions.
We report the repeatability to be better than 50 nm.s−2 . No significant instrumental drift was observed over several weeks
of measurement. This study furthermore investigates whether changes of instrument tilt and external temperature and com-
bination of both, which are likely to occur during field campaigns, influence the measurement of gravitational attraction. We
◦repeatedly tested external temperatures between 20 and 30 C and did not find any significant effect. We report two weeks
of stable operation under semi-terrain conditions in a garage without temperature-control. As an example of a geophysical
signal, a 100 nm.s−2 gravity change is detected with the AQG#B01 after a rainfall event at the Larzac geodetic observatory
(Southern France). The data agreed with the gravity changes measured with a superconducting relative gravimeter (GWR,
iGrav#002) and the expected gravity change simulated as an infinite Bouguer slab approximation. We close with operational
recommendations for potential users and discuss specific possible future field applications. While not claiming completeness,
we nevertheless present the first characterisation of a quantum gravimeter carried out by future users. Crucial criteria for the
assessment of its suitability in field applications have been investigated and are complemented with a discussion of further
necessary experiments.