Speaker
Description
Within the framework of the ARC-ETCRYO project, a scaled prototype of the ET cryogenic payload has been developed. This testbed serves as a fundamental R&D platform to validate the technologies for the cryogenic detector, specifically addressing the challenges of efficient heat extraction and thermal noise mitigation.
This contribution details the design of the payload and its dedicated cooling system, engineered to provide a stable cryogenic environment for the optical components. Particular emphasis is placed on the test mass suspension system, which utilizes a ribbon-based geometry. The core of this presentation focuses on the experimental measurement of the mechanical Quality Factor Q of a reduced-scale sapphire suspension. This component features a fully monolithic sapphire solution, consisting of two ribbon-shaped fibers interfaced at the extremities by two solid sapphire blocks.
We describe the experimental methodology, including the excitation techniques and the readout systems used to characterize the pendulum mode at cryogenic temperatures. The results of the initial characterization are presented.
Finally, we outline the roadmap for upcoming measurement campaigns, which will involve a comparative study of an identical geometry assembled using Hydroxide-Catalysis Bonding (HCB). This comparison is critical for evaluating the trade-offs between mechanical dissipation, thermal conductivity, and assembly scalability for the final ET design.