AC/DC characterization of a Ti/Au TES with Au/Bi absorber for X-ray detection

Abstract

Transition-edge sensors (TESs) are used as very sensitive thermometers and microcalorimeters aimed at different wavelengths detection. In particular, for soft X-ray astrophysics, science goals require very high resolution microcalorimeters which can be achieved with TESs coupled to suitable absorbers. For many applications there is also need for a high number of pixels, which means to be multiplexed in the readout stage. Frequency Domain Multiplexing (FDM) is the baseline readout scheme, proposed for the ATHENA mission. FDM requires biasing the TES in AC at MHz frequencies. Recently there has been reported degradation in performances under AC with respect to DC bias. In order to assess the performances of TESs to be used with FDM, it is thus of great interest to compare the performances of the same device under AC and DC bias. Of course this means using two completely different setups and two different way of thinking the characterization measurements. Here we report the preliminary results of a single pixel characterization performed on a TiAu TES under AC and afterwards under DC bias in different facilities. Extraction of dynamical parameters and noise performances are compared in both cases as a first step for further AC/DC comparison of these devices.