Q-factor of acoustic modes of a solid-state resonator at low temperatures

The acoustic characteristics of a cylindrical sample made of an aluminum alloy (model of gravity detector) in the course of cooling to temperatures on the order of the boiling point of liquid helium are studied. A specialized cryostat with working chamber having a large volume is presented. The technique and results of measurements of the Q-factor of the longitudinal modes of a model weighing 8 kg are described. The results are extrapolated to a cryogenic variant of the OGRAN large-scale (2.3 tons) gravity detector.