Observation of Bias-Specific Telegraph Noise in Large Transition-Edge Sensors

We have observed anomalous random telegraph noise in discrete regions of voltage bias throughout the superconducting transition in larger transition-edge sensors (TESs). The bimodal nature of these noise features is consistent with thermally activated switching across discrete jumps in the TES resistance. When a TES is biased near one of these regions, or the peak of the pulse response samples one of these regions, the energy resolution suffers. In this manuscript, we will present detailed measurements of these noise features in one of our TESs optimized for alpha-particle spectrometry.