Performance test of half-wave resonator (HWR) superconducting cavities

The evaluation of half-wave resonator (HWR) cavity performance is presented in this study. We demonstrate the time-dependent characteristics of the fast cool-down process, as well as the RF conditioning and measurement procedures, including input power, reflected power, and transmitted power. Measurements encompass quality factor, resonance frequency, Lorentz force detuning (LFD), pressure sensitivity, and surface resistance for the HWR cavities. Furthermore, we determine Q slopes at temperatures of 4.2 K and 2 K for these cavities. Utilizing the Q slope data, we calculate the BCS resistance and estimate the bandgap for the Nb HWR cavity.