ETpathfinder
Einstein Telescope Pathfinder
ETpathfinder is a research and development facility for future gravitational wave (GW) observatories, in particular for the Einstein Telescope (ET). In order for ET to achieve its game-changing performance compared to currently existing gravitational wave observatories, such Virgo and LIGO, a variety of innovative techniques (e.g. cryogenically cooled silicon mirrors) need to be developed, tested and qualified for use in ET. ETpathfinder offers a unique testbed for scientists as well as companies, by offering a full interferometer testbed with an ET-like sensitivity. ETpathfinder is situated in Maastricht and run by a collaboration of about 25 research institutes from 8 countries.
Infrastructure and User Services
ETpathfinder offers a testbed in which innovative gravitational wave technologies and concepts to be tested can be tested and qualified in a full interferometer configuration and at a sensitivity of 1e-18m/sqrt(Hz) at 10Hz. ETpathfinder is hosted in a cleanroom of 800 square meters which provides an operational height of 8.5meters. The vacuum system consists of 6 towers (3 m diameter and 6.5m height) connected by 10m long tubes. The total volume is about 190 cubic meter and the target pressure is 1e-9mbar. For cryogenically cooling of the ETpathfinder mirrors, cryostats and heat-shields, a sub-cooled liquid nitrogen infrastructure is available. Custom-made vibration free sorption coolers and kick-starter helium loops will allow operation at temperatures down to 10K. Sophisticated active and passive multi-stage isolators provide the required seismic isolation for the optical in-vacuum benches and mirrors. Ultra-low noise silicon mirrors and pre-stabilised laser systems are available at different wavelengths (1550nm and 2090nm). A fast and powerful custom-made data acquisition and control system is available for controlling the mirrors of the interferometer to picometer accuracy and readout the length of the 10m long optical resonators with sensitivity to better than a 1000th of a proton diameter. Users from knowledge institutes and companies can use ETpathfinder test new devices/techniques and technologies they developed.
Examples/description of the type of research
While there are many small labs across Europe that carry out research on a variety of topics relevant for the Einstein Telescope, those labs do not have the possibility to test i) their technologies in a full interferometer configuration with the interfaces to the relevant subsystems and ii) also have no chance to test their hardware at an ET like sensitivity level. ETpathfinder offers to bring all the new techniques and concepts together and qualifying them for ET. Research topics carried out in ETpathfinder span the full range of topics relevant for Einstein Telescope, including: Low noise lasers, silicon mirrors, low vibration cryogenic cooling, ice formation and reduction test, new thin-film coatings, monolithic silicon suspensions, quantum techniques including squeezed light and quantum non-demolition, photo-detectors, digital control and timing systems, seismic isolation systems, inertial sensors, rotational sensors, active noise mitigation systems, vacuum cleanliness and particle deposition, low noise electro-optical components, ultra-low noise analog electronics, etc.
How to access the infrastructure?
Access to ETpathfinder is generally via collaboration.