A cryogenic and superconducting inertial sensor for the Lunar Gravitational--Wave Antenna, the Einstein Telescope and Selene-physics

Abstract

The Lunar Gravitational-Wave Antenna is a proposed low-frequency gravitational-wave detector on the Moon surface. It will be composed of an array of high-end cryogenic superconducting inertial sensors (CSISs). A cryogenic environment will be used in combination with superconducting materials to open up pathways to low-loss actuators and sensor mechanics. CSIS revolutionizes the (cryogenic) inertial sensor field with a modelled displacement sensitivity at 0.5 Hz of 3 orders of magnitude better than the current state-of-the-art. It will allow the Lunar Gravitational-Wave Antenna to be sensitive below 1 Hz, down to 1 mHz and it will also be employed in the forthcoming Einstein Telescope-a third-generation gravitational-wave detector which will make use of cryogenic technologies and that will have an enhanced sensitivity below 10 Hz. Moreover, CSIS seismic data could also be employed to obtain new insights about the Moon interior and what we can call the Selene-physics.

Research Facilities for Europe’s Next Generation Gravitational-Wave Detector Einstein Telescope

“…The E-TEST prototype aspires to acquire a substrate with a mass, purity and dimensions well on track towards the ET mirrors (45 cm diameter, 210 kg). After polishing, characterisation of the substrate will take place using three experiments of which two are shown in Figure 20: a white light interferometer for precise mirror surface quality characterisation, an interferometric measurement scheme using the silicon substrate as a Fabry-Perot etalon to determine its temperature [100] and mechanical loss measurements of internal mechanical modes using a fm/ √ Hz interferometer [101] excited by a tiny hammer, i.e., a small mass-spring element. Finally, crystalline coating layers are characterised regarding, e.g., their optical and elastic properties, which are important to estimate the noise behaviour of the ultimate coatings.…”