X-ray spectroscopy with the SODART/XSPECT telescope

Abstract

The SOviet-DAnish Röntgen Telescope (SODART) on board the Spectrum Röntgen Gamma (SRG) satellite will be equipped with three different instruments devoted to X-ray spectroscopy. Each of the two thin foil telescopes has an 8 m focal length, a 60 cm diameter, a 1 deg field-of-view (FOV), a <2 arcmin half-power width and ca. 1700 and 1200 cm₂ collecting area at 2 and 8 keV, respectively. Broad band (0.25 – 25 keV) imaging spectroscopy over the full FOV will be obtained from low- and high-energy imaging proportional counters with energy resolution as good as 28 and 14 percent (FWHM) at 1.5 and 6 keV, respectively, and with an efficiency >70 percent (2 – 25 keV). The central 18 arcmin of the FOV of one telescope will be viewed by an array of 19 cooled silicon detectors with energy resolution of 140 and 160 eV at 2 and 6 keV, respectively, and efficiency >85 percent (2 – 20 keV). Each detector element will subtend a 3.4 arcmin FOV. A full FOV objective crystal spectrometer in front of the other telescope will obtain high resolution imaged spectra of point and extended sources with an energy resolution of 2, 1 and 2 eV at 0.7, 2.5 and 6.7 keV, respectively.