{"id":463,"date":"2026-03-05T10:39:08","date_gmt":"2026-03-05T10:39:08","guid":{"rendered":"https:\/\/caos-gw.unipg.it\/what-is-caos\/"},"modified":"2026-05-04T13:41:21","modified_gmt":"2026-05-04T13:41:21","slug":"what-is-caos","status":"publish","type":"page","link":"https:\/\/caos-gw.unipg.it\/en\/what-is-caos\/","title":{"rendered":"What is CAOS?"},"content":{"rendered":"\n<p>CAOS (Center for Gravitational Wave Applications and Seismology) is the international laboratory for the improvement of seismic attenuation systems and the minimization of thermal noise down to the lowest frequencies.<\/p>\n\n<p>Established as part of the development of gravitational wave detectors and founded by the <a href=\"http:\/\/www.unipg.it\/\">University of Perugia<\/a> and <a href=\"http:\/\/www.infn.it\/\">INFN<\/a>, it is one of the primary infrastructures of ETIC (Einstein Telescope Infrastructure Consortium), the project coordinated by INFN and funded under the PNRR (Mission 4 \u2013 Education and Research).<\/p>\n\n<p>Among the main impacts of CAOS is the development of innovative suspension prototypes for current and future gravitational wave detectors, such as <a href=\"https:\/\/www.virgo-gw.eu\/\">Virgo<\/a> and <a href=\"https:\/\/einsteintelescope.eu\/\">Einstein Telescope<\/a>.<\/p>\n\n<p>To measure gravitational waves, second-generation detectors \u2014 <a href=\"https:\/\/www.ligo.caltech.edu\/WA\">LIGO Hanford<\/a>, <a href=\"https:\/\/www.ligo.caltech.edu\/LA\">LIGO Livingston<\/a>, <a href=\"https:\/\/www.virgo-gw.eu\/\">Virgo<\/a>, and <a href=\"https:\/\/gwcenter.icrr.u-tokyo.ac.jp\/en\/\">KAGRA<\/a> \u2014 suppress ground vibrations by more than 10 orders of magnitude for all frequencies above 10 Hz, using chains of mechanical filters housed in Ultra-High Vacuum towers.<\/p>\n\n<p><a href=\"https:\/\/einsteintelescope.eu\/\">Einstein Telescope<\/a>, the third-generation detector, will require chains up to 12 meters long in 15-meter towers, lowering the lower operating limit from the current 10 Hz down to 3 Hz.<\/p>\n\n<p>CAOS features two seismic filtering systems, the Superattenuators, in an improved Advanced Virgo version: two 12-meter filter chains in 15-meter Ultra-High Vacuum towers (10<sup>-8<\/sup> mbar), with an innovative suspended load geometry where the test mass is controlled by a reaction mass that is itself suspended. The 22 meters of internal height provide space for testing, assembly, and innovation.<\/p>\n\n<p><br\/>Understanding the context in which the machine operates is the first step toward controlling it. For this reason, the laboratory has been equipped from the start with advanced instrumentation for environmental characterization, also paving the way for new applications outside of gravitational wave science.<br\/>In addition, developments in electronics, optics, and control strategies have already begun to address one of the project&#8217;s most ambitious challenges: measuring the residual motion of the suspended mirrors, which are over 10 billion times steadier than the laboratory floor.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>CAOS (Center for Gravitational Wave Applications and Seismology) is the international laboratory for the improvement of seismic attenuation systems and the minimization of thermal noise down to the lowest frequencies. Established as part of the development of gravitational wave detectors and founded by the University of Perugia and INFN, it is one of the primary [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-cosecaos.php","meta":{"footnotes":""},"class_list":["post-463","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/pages\/463","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/comments?post=463"}],"version-history":[{"count":1,"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/pages\/463\/revisions"}],"predecessor-version":[{"id":464,"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/pages\/463\/revisions\/464"}],"wp:attachment":[{"href":"https:\/\/caos-gw.unipg.it\/en\/wp-json\/wp\/v2\/media?parent=463"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}