Characterization of Mo/Au Transition-Edge Sensors with Different Geometric Configurations

Abstract

Mo/Au transition-edge sensors exhibit weak-link behavior in the measured temperature, $$T$$ and field, $$B$$ dependence of the critical current $$I_\mathrm{{C}}(T,B)$$ . This is a consequence of the longitudinal proximitization between the Nb electrical bias contacts and the bilayer. Understanding how weak-link superconductivity impacts the resistive transition and the detector energy resolution is of great interest. In this contribution we present studies of $$I_\mathrm{{C}}(T,B)$$ for three devices that have different geometries of metallic depositions on top of the sensor used for noise mitigation and X-ray absorption. Results show that these features change the measured $$I_\mathrm{{C}}(T,B)$$ compared to the previously seen measurements on devices without additional deposition layers. Measurements of the small signal transition parameters $$\alpha $$ and $$\beta $$ also reveal differences between designs that impact the measured response to X-rays and energy resolution.