NbTi Thin-Film SRF Cavities for Dark Matter Search

The search for dark matter is now looking at axion-like particles (ALPs) as a very promising candidate to understand our universe. Within the framework of haloscope detectors for ALPs, we explore the performances of NbTi thin-film coatings on Cu resonating cavities to investigate the presence of axions in the range of 35–45-µeV mass. In this work, two different compositions of NbTi thin films are studied, and their performances in high magnetic field are presented. The chemical treatments and dc magnetron sputtering details of the preparation of three 9-GHz resonant cavities and a 7-GHz resonant cavity are shown along with the cavities’ quality factor measurements at different applied magnetic fields.