Operational evaluation of an industrial differential quantum gravimeter

We report on the recent progress on exail’s Differential Quantum Gravimeter (DQG). Developed by exail quantum sensors (formerly known as muquans). The DQG  measures the acceleration due to gravity and the vertical gravity gradient simultaneously. It is an industry-grade demonstrator that has been operational for three years now and has achieved state-of-the-art sensitivity mainly limited by Quantum Projection Noise down to a noise floor at about 40E/sqrt(tau) and a long-term stability better than 1E [1]. For gravity measurements the performances are on par or better than exail’s AQG with a sensitivity of 600nm/s²/sqrt(tau) and a stability down to 5nm/s². Measuring the acceleration of the Earth gravity g and the gravity gradient simultaneously and at the same location promises enhanced information on the distribution of underground masses, especially at shallow depths [2].

In addition to survey measurements, we report on the DQG evaluation at the the LNE-Trappes characterized gravimetry laboratory near Paris [3]. A comparison to the gravity reference value has shown good agreement. The vertical gravity gradient measurement also compared favorably to the determinations obtained using a spring relative gravimeter both in terms of performance and in terms of ease-of-use.

Finally, we present on-going instrumental developments that will be key to the design of more compact instruments. Such instruments will be the basis for the Horizon Europe project FIQUgS which aims at realizing field compatible commercial gravimeters as well as data processing tools.

 

[1] C. Janvier, et al., “A compact differential gravimeter at the quantum projection noise limit”, Phys. Rev. A 105, 022801 (2022)

[2] G. Pajot, O. de Viron, M. M. Diament, M. F. Lequentrec-Lalancette, V. Mikhailov, Geo-Physics 73, 123 (2008).

[3] S. Merlet, et al., “Micro-gravity investigations for the LNE watt balance project” Metrologia vol 45 265 (2008)