Performance of superconducting transition edge bolometers for infrared photometry and X-ray micro-calorimetry

The performance of voltage biased superconducting transition edge bolometers for infrared photometry and X-ray micro-calorimetry is described. Experimental results for the resistance–temperature curve of the superconducting phase thermometer, the current–voltage characteristic of the bolometer, and its current noise are presented and evaluated. Excess current noise turns out to be present when the bolometers are biased in the superconducting transition. The possible origin of this excess noise is shortly discussed. For the infrared bolometer an NEP of 2 ×10−17 W/Hz at 270 mK is obtained. The X-ray micro-calorimeter resolution is 60 eVFWHM at 155 mK for 5.9 keV X-rays, a factor 2.6 above the thermodynamical limit.