E3S Web Conf.
Volume 12, 2016i-DUST 2016 – Inter-Disciplinary Underground Science & Technology
|Number of page(s)||6|
|Published online||05 December 2016|
First analyses of the iOSG-type superconducting gravimeter at the low noise underground laboratory (LSBB URL) of Rustrel, France
1 Institut de Physique du Globe de Strasbourg, UMR 7516, Université de Strasbourg/EOST, CNRS,5 rue Descartes, 67084 Strasbourg, France
2 LSBB URL, France
3 Université Côte d'Azur, CNRS, Observatoire de la Côte d'Azur, IRD, Géoazur, France
a Corresponding author: email@example.com
In the last few years, the performance of the cryogenic gravity instruments has been further improved by the development of a new generation of superconducting gravimeter (SG): the so-called iOSG which is a superconducting gravimeter designed for observatory purpose with a heavier sphere than previous SGs. The first iOSG (iOSG-024) has been installed in July 2015 at the LSSB low background noise underground research laboratory in Rustrel (France), funded by the EQUIPEX MIGA (Matter wave-laser based Interferometer Gravitation Antenna) project and by the European FEDER 2006-2013 “PFM LSBB – Développement des qualités environnementales du LSBB”. This instrument is operational since September 2015. We present the first tidal analyses of the 7-month time-varying gravity records of this newly installed instrument as well as the calibration results performed by parallel FG5 absolute gravity measurements. We also show the performances of iOSG-024 in terms of noise levels in the seismic (in the millihertz frequency range) band using a standardized procedure based on the computation of the residual power spectral densities over a quiet time period. The obtained noise levels are compared with other SG sites and with seismological reference noise models. The combination of the instrumental performance of the iOSG with the LSBB site properties makes this gravimetric station one of the quietest in the world, comparable to the lower sensor of the OSG-56 at BFO, at seismic frequencies.
© The Authors, published by EDP Sciences 2016
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).