Speaker
Description
The ET-FIBER project is a collaborative R&D initiative, focused on developing silicon fibers for suspending a 70 kg monocrystalline silicon test mass in the ET-CRISTAL prototype. ET-CRISTAL serves as a critical cryogenic prototype for the Einstein Telescope, which operates a large monocrystalline silicon mirror cooled radiatively to 20–25 K, while achieving low seismic noise below 10 Hz through advanced vibration isolation. In this context, ET-FIBER aims to design, manufacture, and characterize silicon fibers capable of supporting these large test masses under cryogenic conditions, while meeting the stringent mechanical and thermal noise requirements of next-generation detectors.
This poster will present the current state of the project and its challenges. This includes two mechanical designs with different working principles. The first design is comparable to what is used in the gravitational waves detectors of the previous generation, meaning components loaded only in tension. The challenge is to manufacture rods that are long but thin. Indeed, vibration is induced during the machining process. This can be harmful for the material since silicon is brittle. One of the studied solutions is to produce smaller parts that will be welded together. The machining process itself is also under development by the concerned partner. The second design is composed of tensional and compressive parts. The starting point of this design is the fact that the silicon exhibits a higher mechanical strength in compression. This could be used by making the flexible parts of the design very thin, which would improve the isolation and reduce the thermal noise of the structure by improving its dilution factor. Then, for those two designs, a first estimation of thermal noise will be shown along with a modal analysis. This modal analysis includes the transfer function from the clamping of the suspension to the mirror. It demonstrates the suspension role as an additional filtering stage for the mirror.