Spatially resolved study of superconducting tunnel junctions x-ray detectors by low temperature scanning synchrotron microscopy

A low temperature scanning synchrotron microscope (LTSSM) has been develope d for spatial analysis of superconducting tunnel junction X-ray detectors. One and two-dimensional images of the detector response to X-rays were meas ured by scanning the junctions kept at a working temperature of about 0.4 K with a highly collimated synchrotron radiation beam. The collimation was p erformed by inserting a pinhole mounted on a scanning unit into the synchro tron radiation in the range of 3-6 keV. The spatial resolution of the LTSSM is between 5 and 10 micrometer. The present results indicate a large discr epancy between the experimental spatial response and a quasiparticle diffus ion and edge-toss model. The LTSSM plays an important role in the developme nt of cryogenic X-ray detectors.