Speaker
Description
Seismic attenuation is a crucial aspect for the mirrors used in Gravitational Wave (GW) interferometric experiments, as the RMS ground motion is many orders of magnitude higher than the signal to be detected. For this reason, technologies capable of efficiently attenuating vibrations in high mass systems have been extensively developed in this field.
In this talk, we introduce cantilever spring blades, a mechanical passive element effectively used for vertical seismic attenuation in the main mirrors of Virgo and its upgrades. Their attenuation capability relies on the low-pass filtering behavior of a harmonic oscillator: the lower the resonance frequency, the stronger the attenuation above the cutoff.
This approach is well-suited for high mass payloads, but the main technological challenge lies in achieving sufficiently low stiffness while still providing reliable mechanical support against gravity. Cantilever spring blades have been specifically developed to address this issue, with maraging steel emerging as an excellent material choice due to its high mechanical strength, low creep sensitivity, and suitability for cold forming and heat treatment.
For future third-generation GW interferometers such as the Einstein Telescope (ET), even more demanding performance requirements and stricter environmental constraint -especially those related to cryogenics- will apply. For these reasons, the development and characterization of alternative materials for this application will soon become essential.