Self-cooling cryogenic microcalorimeters made of SINIS junctions

High quality low leakage SINIS devices made of Al-AlMn-Al layers were fabricated for energy dispersive single photon detection. Information on different heat flow channels was extracted from the measured dynamics of detector signals due to X-ray events. At the optimum operation point, the extracted effective electron temperature decreased from 88 mK down to 43 mK due to self-cooling, roughly doubling the detector sensitivity.