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ET in Italy

The pillars of Italy’s candidacy to host the Einstein Telescope in the area of the disused Sos Enattos mine (Sardinia) are:  the ideal site for ensuring the best operating conditions, a history of success in gravitational wave research, the multidisciplinary excellence of national scientific research, and strong institutional, scientific, and civic support.

Italy’s candidacy is supported by the Italian government, the Ministry of Universities and Research (MUR), and the Autonomous Region of Sardinia. It is scientifically coordinated by the INFN (the Italian National Institute for Nuclear Physics) in collaboration with other research organisations and universities throughout Italy.

The italian tradition

Italy has been involved in the experimental research into gravitational waves from the outset and has been a leader throughout its history.

The country’s role in this area and in the Einstein Telescope project is internationally recognised. in In 2020 Italy, alongside MUR, led the group of European nations that submitted the ET’s candidacy to the European Strategy Forum on Research Infrastructure (ESFRI). This forum recognised the project as one of the main European ones and included it in its Roadmap2021 of major research infrastructures it is important to invest in [link].

The Italian history in gravitational wave research began in 1970, when studies for the first experiments kicked off, thanks to the work of the Roman group of Edoardo Amaldi and Guido Pizzella on so-called resonant antennas at very low temperatures. In the 1990s, the Auriga antennas at the INFN Legnaro National Laboratories and Nautilius at the INFN Frascati National Laboratories began operating. These instruments were not yet sensitive enough to pick up the very weak vibrations of space-time. In the mid-1980s, the Italian Adalberto Giazotto and Frenchman Alain Brillet had begun studying the development of a new class of experiments based on a completely different detection technique: laser interferometry. Thus, the Virgo project was launched in Italy, joined by the LIGO project in the United States. In 2000, the INFN and the French CNRS founded the European Gravitational Observatory (EGO) near Pisa to house and manage the project, while the detector would become fully operational in 2007. A decade later, thanks to major upgrades to the Virgo and LIGO interferometers, for the historic gravitational wave discoveries to come to fruition, in 2015.

The success of these achievements underlined how crucial the development of a new generation of gravitational observatories is now to move beyond the limits of current instruments. This is the purpose of the Einstein Telescope project: build an observatory in Europe capable of ‘listening’ to the cosmos up to eras very close to the big bang. The scientific undertaking, therefore, continues and Italy’s contribution will be crucial.

SOS Enattos, the ideal site

Inland Sardinia is an ideal place to host Einstein Telescope.

The Italian Sos Enattos site is currently competing with another candidate site from the Netherlands, located in an area of the Meuse-Rhine Euroregion, on the border between the Netherlands, Belgium, and Germany.

There are many geological reasons why the Sos Enattos area is an ideal place for the ET activities. Seismic noise, which affects detector performance at low frequencies, is very low due to the geological characteristics of Sardinia. Sardinia is, in fact, a microplate, i.e., a detached portion of the Eurasian plate that is not connected to the most active tectonic zones. Thus, the region is not affected by crustal deformation phenomena or seismicity and volcanoes. In fact, it is a stable and solid area, characterised by rock masses that are ideal for safely building the underground spaces that will constitute the ET laboratory. Moreover, the limited presence of groundwater in the area reduces the possibility of seepage or seismic and Newtonian noise.
Finally, in the area around Nuoro, between the municipalities of Bitti, Lula and Onanì, there are large expanses of rural areas with very low population density and, therefore, limited anthropogenic and industrial activity.
All this makes the Sos Enattos site the ‘silent’ environment that ET needs, to operate protected and insulated from the ‘noise’ that would compromise its measurements.

The SAR-GRAV Laboratory. The former Sos Enattos mine is already a place for scientific research: since 2019, it hosts the SAR-GRAV laboratory with the Archimedes experiment. Funded by the Sardinia Region, the SAR-GRAV laboratory was established under a Programme Agreement between the Sardinia Region and the University of Sassari, the INFN, the National Institute for Geophysics and Volcanology (INGV), the University of Cagliari, and IGEA S.p.A., the company that manages the mine. The aim of the project is to build a facility with low seismic and anthropogenic noise dedicated to research on gravitational waves, gravitational physics, and geophysics. SAR-GRAV is currently hosting and supporting the site’s seismic analysis activities for its candidacy.
Archimedes is an INFN-funded fundamental physics experiment that searches for small weight variations induced by quantum fluctuations. The experiment needs an environment in which external seismic factors do not influence the measurement: hence the decision to install it in the SAR-GRAV laboratory. However, Archimedes is also working for the ET, verifying the suitability of the Sos Enattos site. Thanks to its extreme sensitivity, Archimedes will develop a detailed profile of the environmental and anthropogenic disturbance of the area of the former mine.

The technical and scientific committee for the italian candidacy

On 9 February 2023, theMinistry of Universities and Research (MUR) established a high-profile Technical and Scientific Committee in order to support at best the Italian candidacy by decree of Minister Anna Maria Bernini. The committee is chaired by the Physics Nobel Laureate Giorgio Parisi, and encompasses Ambassador Ettore Sequi, former secretary general of the Ministry of Foreign Affairs and International Cooperation, as well as the scientists Professors Marica Branchesi and Fernando Ferroni of the Gran Sasso Science Institute and the INFN, and Professor Antonio Zoccoli, President of the INFN itself.

NRRP projects supporting the ET

ETIC, Einstein Telescope Infrastructure Consortium

This project is funded by 50 million euros by the NRRP National Recovery and Resilience Plan (Next Generation EU), under Mission 4 Education and Research, coordinated by the MUR. The project was created and developed as part of the international Einstein Telescope project with two main objectives. The first one was to carry out a feasibility and analysis study of the Sos Enattos site. The second one was to establish or enhance a national network of R&D laboratories at the INFN sites, universities, and research institutions participating in the ET project. This network studies enabling technologies for the future interferometer, specifically seismic filtering, and low-frequency control systems for suspending the optics, low-noise cryogenic apparatus for thermal noise abatement in the optics, new technologies in photonics, optics and electronics, and, finally, new materials to implement the Einstein Telescope mirrors.


This project is part of the larger MEET project, led by the National Institute for Geophysics and Volcanology (INGV) and funded with 43 million euros by the NRRP National Recovery and Resilience Plan (Next Generation EU), under Mission 4 Education and Research, coordinated by the MUR. MEET’s overall goals are the improvement, technological upgrade, and implementation of large scientific networks to monitor and observe the Earth. Specifically, FABER‘s goal, in support of the ET’s candidacy, is to develop a seismological observatory in the former Sos Enattos mine in order to record seismic signals that are currently unknown. Sos Enattos provides a special observation point where the absence of seismic activity, quiet, and geodynamics ensure the highest quality geophysical data. The INGV has been operating in the Sos Enattos mine since 2019, both in collaboration with the Universities of Cagliari and Sassari and the INFN, as well as with independent research projects such as the MedNet (Mediterranean Seismic Network) station, the data gathered by which fed the INGV’s seismic monitoring network.


TeRABIT is funded with 41 million euros by the National Recovery and Resilience Plan (Next Generation EU), under Mission 4 Education and Research, coordinated by MUR. It is managed by the INFN with the National Institute for Oceanography and Experimental Geophysics (OGS), the GARR Consortium, and CINECA. The project will implement an integrated ultra-high-performance computing and network infrastructure, based on highly reliable next-generation dedicated fibre optics, which will allow data to be exchanged at the speed of one terabit (1 trillion bits) per second. Scientific communities throughout the country, regardless of geographic location, will be able to access the new infrastructure, eliminating differences in the ability to access high-performance computing and promoting collaboration and competitiveness. In Sardinia TeRABIT will specifically implement a fibre-optic extension of the island’s research network and, for the first time, thanks to submarine cables, build a double superfast fibre-optic link, which will ensure not only rapid data transmission but also system redundancy and reliability, benefiting the entire scientific community on the island. The infrastructure built by TeRABIT will be instrumental in supporting Sardinia’s candidacy to host the Einstein Telescope project, a research facility that will produce large amounts of data to be shared with a scientific community spread across the planet. The ultrafast interconnection of the Sos Enattos site is therefore a crucial element.

Banner image: Overview of the Sos Enattos mine. Credits: INFN-EGO