An X-ray photon-counting imaging spectrometer based on a Ta absorber with four superconducting tunnel junctions
Publication date: 15 January 2000
Authors: den Hartog, R., et al.
Journal: Proc. 8th International Workshop on Low Temperature Detectors
We present the first results obtained with a 2-dimensional X-ray imaging spectrometer consisting of a 200x200 micron² Ta absorber and read out by four Ta/Al superconducting tunnel junctions (STJs). A preliminary image reconstruction algorithm allows the visualisation of the diffraction pattern from a 5 micron pinhole illuminated with 10 keV X-rays. The image suggests a spatial resolution better than 10 micron. The algorithm does not take into account quasi-particle losses in the absorber. Hence, the pulse height reconstruction is not optimal and the energy resolution varies significantly across the absorber. The best energy resolution is obtained for a 20x20 micron² area in the centre of the absorber, and amounts to ~77 eV at a photon energy of 5895 eV, with a 70 eV electronic noise contribution.Link to publication