Freiburg 2024 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 56: Poster VII
Q 56.23: Poster
Donnerstag, 14. März 2024, 17:00–19:00, KG I Foyer
State-of-the art suppression of seismic noise for Very Long Baseline Atom Interferometry — •Kai C. Grensemann, Jonas Klussmeyer, Klaus Zipfel, Ernst M. Rasel, and Dennis Schlippert — Leibniz Universität Hannover, Institut für Quantenoptik
The Hannover Very Long Baseline Atom Interferometer (VLBAI) facility offers exciting capabilities for absolute precision gravimetry with applications in geodesy and tests of fundamental physics. Its 10 m baseline enables free fall times of up to 2T=2.4 s and therefore large measurement sensitivity scale factors keffT2. However, the sensitivity to vibrational noise of the inertial reference mirror increases similarly. To attenuate seismic vibrations coupling to the mirror, the VLBAI facility is equipped with a state-of-the-art in-vacuum seismic attenuation system (SAS).
Here we present the recently installed SAS with its range of featured sensors and actuators, as well as a first benchmark of the passive vibration attenuation performance. Passive attenuation in all degrees of freedom is achieved by three sets of inverted pendula suspended from geometric antispring filters with a low vertical resonance frequency of 320 mHz. Residual motion at the resonance can be damped actively using three seismometers spread over the suspended platform and six voice coil actuators in a feedback loop. Furthermore, a central out-of-loop low-noise seismometer provides data to post-correct the interferometer measurements. We estimate that the SAS in combination with post-correction will allow instabilities of ≈ 4· 10−10 m/s2 at 1 s, close to the shot-noise limit of ≈2·10−10 m/s2 for 106 atoms.
Keywords: Seismic noise attenuation; Atom interferometry; Precision measurements