ADMX Cold Electronics Design for A Multicavity System

The Axion Dark Matter eXperiment (ADMX) has already eliminated significant parameter space for the QCD axion at DFSZ sensitivities and in mass ranges at which it is believed to be able to account for dark matter abundances. As the experiment moves to higher microwave frequencies to exclude axions of higher masses, it must contend with decreasing cavity size, which translates to a smaller per-cavity detection volume. To mitigate this issue and maintain a high scan rate at these sensitivities, ADMX is moving to a multi-cavity setup. Run 2A, the next stage for the current ADMX G2 experiment, will consist of a 4-cavity system, preparing the way for an eventual 18-cavity array in ADMX EFR. This allows the experiment to maintain a large detection volume and high scan rate but increases complexity in the cold electronics design and operation. We will discuss our work on designing and building new amplifiers and a new multichannel cold electronics system for the next generation of ADMX.