https://doi.org/10.1140/epjp/s13360-021-01993-w
Regular Article
Picoradiant tiltmeter and direct ground tilt measurements at the Sos Enattos site
1
Università di Napoli Federico II - Via Cinthia, I-80126, Naples, Italy
2
INFN - sez. Napoli - Via Cinthia, I-80126, Naples, Italy
3
Centro Nazionale Ricerche - Istituto Nazionale di Ottica (CNR-INO), Firenze, Italy
4
Università di Roma La Sapienza, I-00185, Roma, Italy
5
INFN - sezione di Roma 1, I-00185, Roma, Italy
6
Università degli Studi di Sassari, I-07100, Sassari, Italy
7
INFN - Laboratori Nazionali del Sud, I-95125, Catania, Italy
8
European Gravitational Observatory (EGO), Via E Amaldi, 56021, Cascina, PI, Italy
9
Università degli Studi di Milano Bicocca, I- 20126, Milano, Italy
10
INFN - sezione di Milano-Bicocca, I - 20126, Milano, Italy
11
Centre de Physique Theorique Campus of Luminy - Case 907, F-13288, Marseille, France
12
Aix-Marseille Universié Site du Pharo, 58 bd Charles Livon, F-13284, Marseille, France
13
Université de Toulon - Campus de La Garde - La Valette Avenue de l’Université, La Garde, F-83130, Toulon, France
Received:
21
July
2021
Accepted:
24
September
2021
Published online:
25
October
2021
We report the tilt sensitivity reached by the ARCHIMEDES tiltmeter in the 2–20 Hz frequency region, where seismic noise is expected to give an important limitation to the sensitivity in the next future Gravitational Waves detection, particularly through Newtonian noise. The tilt noise level 
is about 
in most of the band, reaching the minimum of 
around 9 Hz. The tiltmeter is a beam balance with a 0.5 m suspended arm and interferometric optical readout, working in closed loop. The results have been obtained by a direct measurement of the ground tilt at the Sos Enattos site (Sardinia, Italy). This sensitivity is a requirement to use the tiltmeter as part of an effective Newtonian noise reduction system for present Gravitational Waves detectors, and also confirms that Sos Enattos is among the quietest sites in the world, suitable to host the third-generation Gravitational Waves detector Einstein Telescope.
© The Author(s) 2021
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