Development of High-Q Superconducting LC Resonators for DMRadio

A superconducting lumped-LC resonator is a central piece in the search for sub-μeV axions with DMRadio. It enhances the axion signal and allows much more sensitive searches by increasing the signal-to-noise ratio and improving the experiment scan rate. We have demonstrated a prototype resonator with a state-of-the-art quality factor, Q ≥ 10⁶, which satisfies the requirement for the DMRadio-50L. The results have a direct impact on the design and implementation of the resonator for DMRadio-50L by providing a recipe for achieving a high-Q value in the desired frequency range. The results also inform the resonator design approach for the future GUT-scale QCD axions search with DMRadio-GUT. I will present the latest findings from our research and development project studying loss mechanisms in these resonators and scaling up this prototype resonator for integration into DMRadio-50L, as well as routes for further improving the quality factor.