Angular effects of gamma radiation on sapphire coplanar waveguide microwave resonators

Niobium superconducting microwave resonators on a c-plane sapphire were used to study the effects of radiation on devices used for quantum information. Coplanar waveguides were exposed to gamma radiation from different incidence angles during active resonance frequency and internal quality factor measurements. The radiation source was a closed Cesium-137 source. The measurements show a consistent degradation in internal quality factor for each measured sapphire resonator. The shift in resonance frequency ranges from 50 kilohertz to 136 kilohertz. The downward shift is more significant in both measurements where the radiation is incident parallel to the sample rather than perpendicularly.