E-TEST Prototype


Discover our unique E-TEST prototype of suspended mirror in cryogenic conditions (25Kelvin), on it’s way to be built at the Liège Space Center (CSL) in Liège, Wallonia, Belgium!

Our E-TEST scientists are developing fully innovative and advanced concepts for optics, cryogenics and seismic isolation, that are the key innovative elements for the Einstein Telescope, the new generation observatory of gravitational waves that may be built in the Belgian-Dutch-German border region as of 2025!

The first two years of the E-TEST project were devoted to the design of this unique prototype, and we have just completed the final design. The construction of the facility – a large suspended silicon mirror at cryogenic temperature to improve, validate and test vibration control for gravitational wave telescope at ultra-low temperature (25 Kelvin) and under vacuum, will now start in 2022 at the Liège Space Center (CSL) at the University of Liège.

Overview of the E-TEST prototype design. A large vacuum tank (left) hosts the cryogenic mirror suspension (right). From top to bottom we can see 1) the top GAS filter, 2) the top stage, 3) the marionette and 4) the inverted pendulum legs within pipes that support a reference ring below the top stage. The cryogenic part features 5) the inner cryostat which has the interlacing fin type heat exchanger. The whole cryostat features (6) three access points for outside experiments to interact with the cryogenic mirror. The inner cryostat is attached to 7) the cold platform. The inner cryostat fins interlace into the fins of the 8) outer cryostat which provides a cold environment and houses the (9) 100 kg silicon mirror. All of this is supported by 10) an active platform, which provides a stable and quiet environment. In turn, the active platform hangs from three large blades which have a (11) support pillar on the ground.

E-TEST Conceptual Design Report (E-TEST CDR)

The final Conceptual Design Report (CDR) for the E-TEST Prototype is now available from June 1st 2022. It can be downloaded here:

Einstein telescope Design Report (ET DR) – update 2020

Please also find here the complete DR for the Einstein telescope:

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