Characterization of the temperature dependence of the quality factor of a silicon substrate using the gentle nodal suspension method

In this work, we present the proof of concept of a characterization of the temperature dependence of the quality factor Q(T) for a massive silicon substrate suspended in a cryogenic environment using the gentle nodal suspension (GeNS) method. Measurements were conducted in a low-vibration cryostat, analyzing three distinct resonant vibrational modes of the sample. Quality factor values and associated uncertainties were extracted using multiple statistical approaches. The results highlight the suitability of the experimental method and confirm crystalline silicon as a promising material for test masses in cryogenic conditions, as required in next-generation gravitational wave detectors. A comparison between experimental data and finite element simulations confirms the accuracy of the setup. This study, part of the broader development of monolithic silicon suspensions, demonstrates the effectiveness of the GeNS technique for assessing mechanical dissipation in large-scale substrates.