Probing The Phase Transition Of Mo/Au Tes Microcalorimeters

We present recent measurements obtained using a new method for characterizing transition edge sensor (TES) calorimeters: We measured the electrical impedance of a TES calorimeter throughout the superconducting to normal metal phase transition. The impedance method enables us to precisely measure how the resistance and heat capacity of the TES varies throughout the phase transition. These measurements probe the internal state of our Mo /Au TES. We also present recent results from measurements of noise in our TESs. Our measurements are instrumental toward understanding and optimizing our TES calorimeters.