ADMX-Orpheus: A Dielectrically-Loaded Fabry-Perot Resonator to Search for Higher Mass Axions

Axions in our local dark matter halo could be detected using an apparatus consisting of a resonant microwave cavity threaded by a strong magnetic field. The ADMX experiment uses this technique to search for axions in the few micro-eV mass range. However, the ADMX search technique becomes increasingly challenging with increasing axion mass. This is because higher masses require smaller-diameter cavities, and a smaller cavity volume reduces the signal strength. Thus, there is interest in developing more sophisticated resonators to overcome this problem. The ADMX-Orpheus experiment uses a dielectric-loaded Fabry-Perot resonator to search for axions with masses approaching 100 micro-eV. We present progress on the cryogenic prototype.