Tuning Systems and Bead Pull Measurements for the ADMX-Run2a 4-Cavity Array

The Axion Dark Matter eXperiment (ADMX) searches for the hypothetical axion as a dark matter candidate in the Milky Way halo using high-Q cavity resonators and quantum amplifiers to reach DFSZ sensitivity. After scanning the 2–4 μeV mass range with a single cavity, the upcoming run will deploy a 4-cavity array, combining their signals coherently to extend coverage up to ~7 μeV without reducing the magnet volume. The 4-cavity array design has evolved through several years of R&D, including extensive RF and bead-pull tests. Both piezo and stepper-motor tuning systems have been implemented and evaluated. This talk will summarize recent design choices and performance results from the 4-cavity array development.