Pulse Discrimination and Filtering of X-Ray Ti/Au TESs Using Principal Component Analysis

We develop X-ray transition-edge sensors (TESs) based on Ti/Au bilayers with Au absorber deposited on the center of TES. The thermal conductance after etching the silicon substrate underneath the TES sensor is reduced to 530 pW/K, only ∼10% that before etching, which agrees well with thermal simulation using COMSOL software. Principal component analysis is adopted to simultaneously discriminate the true pulse traces from the false ones and improve the signal-to-noise ratio by ∼20 dB. The obtained energy resolution is 102 eV at 5.9 keV for etched TES device. In addition, we perform complex impedance measurement to extract the parameters of thermal capacity, temperature and current sensitivity, which is very useful to understand the dynamics of TESs.