Gravity field modelling for the Hannover 10 m atom interferometer
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ORIGINAL ARTICLE
Gravity field modelling for the Hannover 10 m atom interferometer Manuel Schilling1,2 Dennis Schlippert3
· Étienne Wodey3 · Ludger Timmen2 · Dorothee Tell3 · Christian Schubert1,3 · Ernst M. Rasel3 · Jürgen Müller2
· Klaus H. Zipfel3
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Received: 19 March 2020 / Accepted: 10 October 2020 / Published online: 27 November 2020 © The Author(s) 2020
Abstract Absolute gravimeters are used in geodesy, geophysics and physics for a wide spectrum of applications. Stable gravimetric measurements over timescales from several days to decades are required to provide relevant insight into geophysical processes. Users of absolute gravimeters participate in comparisons with a metrological reference in order to monitor the temporal stability of the instruments and determine the bias to that reference. However, since no measurement standard of higher-order accuracy currently exists, users of absolute gravimeters participate in key comparisons led by the International Committee for Weights and Measures. These comparisons provide the reference values of highest accuracy compared to the calibration against a single gravimeter operated at a metrological institute. The construction of stationary, large-scale atom interferometers paves the way for a new measurement standard in absolute gravimetry used as a reference with a potential stability up to 1 nm/s2 at 1 s integration time. At the Leibniz University Hannover, we are currently building such a very long baseline atom interferometer with a 10-m-long interaction zone. The knowledge of local gravity and its gradient along and around the baseline is required to establish the instrument’s uncertainty budget and enable transfers of gravimetric measurements to nearby devices for comparison and calibration purposes. We therefore established a control network for relative gravimeters and repeatedly measured its connections during the construction of the atom interferometer. We additionally developed a 3D model of the host building to investigate the self-attraction effect and studied the impact of mass changes due to groundwater hydrology on the gravity field around the reference instrument. The gravitational effect from the building 3D model is in excellent agreement with the latest gravimetric measurement campaign which opens the possibility to transfer gravity values with an uncertainty below the 10 nm/s2 level. Keywords Atom interferometry · Gravity acceleration · Absolute gravimetry · Gravimeter reference
1 Introduction A variety of applications in geodesy, geophysics and physics require the knowledge of local gravity g (Van Camp et al. 2017). These applications include observing temporal varia-
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Manuel Schilling [email protected] Ernst M. Rasel [email protected]
1
Present Address: Institute for Satellite Geodesy and Inertial Sensing, German Aerospace Center (DLR), c/o Leibniz Universität Hannover, DLR Institut, Welfengarten 1, 30167 Hannover, Germany
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Institute of Geodesy, Leibniz University Hannover, Schneiderberg 50, 30167 Hannover, Germany
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