Development of a New TES Structure Using a Radiation Absorber Self-Adjusting the Operating Temperature

We propose a new structure of a TES and a series connection of radiation absorber, which can stabilize the absorber temperature through a negative feedback process in the absorber. We consider that this structure of the self-heating absorber might allow TES to improve detection efficiency with large effective area and high count rate by the cooling power inside the absorber. The 150 mum times 150 mum gold film absorber and the 25 mum times 25 mum heat sensor made by Iridium/Gold bi-layer superconductor which has a Tc of 110 mK are biased in series. In this device the gold film absorber generates the self Joule heating to a certain extent to maintain the temperature of the TES pixel. By the photon incidence to the gold film absorber, thermalization of the heat sensor induces the large current reduction, then the current through the gold film absorber also reduces, therefore the gold film absorber is expected to be cooled rapidly by the reduction of joule heating power. This TES pixel achieves the energy resolution of 34 eV (FWHM) @ 5.9 keV and the time decay constant of 150 mus. Furthermore, we tried to perform the experiment of X-ray fluorescence analysis in the SPring-8 synchrotron facility. This TES pixel succeeded to resolve into the energy peaks derived from the material elements which contained in a stainless steel sample.