Pulse Shape Analysis in Low-temperature Calorimeters Read-Out by NTD Thermistors

We present the application of a simplified thermal model for the description of the response function of low-temperature calorimeters consisting of TeO 2 crystals read-out by NTD thermistors operated at temperatures T ∼ 10 mK. Relying on both the analysis of the NTD load curves (from which we measured the main thermal conductances of the system) (Biassoni et al. in J Low Temp Phys 206:80–96, 2022) and on the analysis of the shape of thermal pulses acquired at different temperatures, we identified and quantified the physical parameters that determine the characteristic time constants of the pulses. In particular, we identified three different contributions to the heat capacity of the detector: the crystal phonon system (scaling as T 3 ), the NTD electron system (scaling as T ) and a term related to the metalization process of the NTD electrodes (scaling as T - 2 ).