Optical Transition-Edge Sensors Single Photon Pulse Analysis

Transition-edge sensors (TES) are detectors able to count single photons from x-ray to infrared, generating pulses with amplitudes proportional to the absorbed photon energy. The TES performance depends on the sensor parameters and also on the noise level. The evaluation of the energy resolution is thus dependent on the type of signal analysis applied. In this work we report the results of an off-line analysis applied to pulses measured with a TiAu TES for the optical region. The pulses were acquired with a digital oscilloscope and further elaborated with numerical methods. Different kinds of digital filters were applied for improving the TES energy resolution, starting from simple Savitzky-Golay filters to more complex Wiener filters. Particular attention was paid both to time-domain and frequency-domain analyses. The first aims to extract features of interest as the photon pulse amplitude, arrival time and time jitter. The second can help for better energy resolution, aiming to identify and enhance only the photon pulse frequency components and reducing the noisy ones