Pushing the limits of a Differential Quantum Gravimeter

Abstract

International audienceMeasuring the acceleration of the Earths gravity g and the gravity gradient simultaneously and at the same location promises to provide enhance information about the distribution of underground masses, especially at shallow depths [1]. Quantum sensors relying on Atom Interferometry with laser cooled-atoms [2,3] is a technology of choice to implement such new sensing capability and an industry-grade demonstrator has been recently developed. We present the performance of the device that has been integrated and discuss its stationary measurement capability, with the demonstration of a resolution below 1E for the measurement of the vertical gravity gradient (1E = 10-9 s-2 = 0.1 Gal/m) and 0.5 Gal for the measurement of g. In order to illustrate the potential for mass balance monitoring and gravity survey we will present a proof-of-principle experiment with realistic masses and measurement durations. The compactness of the instrument and the field-tested technology [4] on which it is based allows to consider the deployment of this new sensor in real environment as a future short-term outcome to investigate both spatial and temporal mass balance in the field. Promising case studies will be discussed, as this type of sensor can sense mass changes that are not detected by gravimeters. [1] G. Pajot, O. de Viron, M. M. Diament, M. F. Lequentrec-Lalancette, V. Mikhailov, Geophysics 73, 123 (2008) [2] R.Geiger, A.Landragin, S.Merlet, F. Pereira Dos Santos, AVS QuantumScience 2, 024702(2020) [3] V. Menoret et al., "Gravity measurements below 109 g with a transportable absolute quantum gravimeter", Nature Scientific Reports, vol. 8, 12300 (2018) [4] A.-K. Cooke, C. Champollion, N. Le Moigne, Geoscientific Instrumentation, Methods and Data Systems Discussions 2020, 1 (2020