Hard x-ray concentrator experiment for Spectrum-X-Gamma mission

Abstract

Hard X-ray concentrators based on glass poly-capillary lenses (Kumakhov optics) can bring new flavor for the next generation of astrophysical instruments. We discuss the advantage of such a concentrator for missions such as new Spectrum-X-Gamma, for both scanning and pointing observational modes. Even though an X-ray concentrator has no true imaging capabilities and therefore can not compete with grazing incident mirror instruments, it could be quite useful. For pointing observations the instrument with large area poly-capillary glass concentrator combined with small CZT detector sensitive in the 5-80 keV energy range would significantly improve the faint point sources spectroscopy in hard X-rays. This is of particular interest due to recent INTEGRAL and Swift discovery of the large number of obscured AGNs and comparison of their spectra with the spectrum of the cosmic hard X-ray background. The other important areas to be explored are detection of the Ti-44 line in the supernova remnants and detailed study of high-energy hyrolines in the spectra of X-ray pulsars. The expected parameters of the instrument show that it could be an order of magnitude more sensitive compared to standard coded aperture telescopes. We also explore the potentials of the X-ray concentrator in the scanning mode during the survey phase of the mission.