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,hbox {nm}{/}{hbox {s}^{2}} 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},hbox {nm}{/}{hbox {s}^{2}} level.
Highlights
A variety of applications in geodesy, geophysics and physics require the knowledge of local gravity g (Van Camp et al 2017)
Time- and space-varying electromagnetic and gravity fields along the free-fall trajectories of the matter waves have a direct impact on the accuracy and stability of the instrument, as the corresponding spurious forces depart from the assumptions of Eq (1), thereby leading to biases (D’Agostino et al 2011) and impacting the instrument’s effective height (Timmen 2003)
Based on the extensive groundwater level recordings from the gauge nearby the Hannover Institute of Technology (HITec) building, we study the impact of groundwater level changes on gravitational attraction inside the building, along the Very long baseline atom interferometry (VLBAI) main and validation profiles, as well as in the gravimetry laboratory
Summary
A variety of applications in geodesy, geophysics and physics require the knowledge of local gravity g (Van Camp et al 2017).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
