On-ground calibration of the ART-XC/SRG mirror system and detector unit at IKI. Part III

• DOI: 10.1007/s10686-019-09646-8
• Publication Date: 2019-12-02T11:57:56Z
• Authors: M. Pavlinsky; A. Tkachenko; V. Levin; A. Krivchenko; A. Rotin; M. Kuznetsova; I. Lapshov; R. Krivonos; A. Semena; N. Semena; D. Serbinov; A. Shtykovsky; A. Yaskovich; V. Oleinikov; A. Glushenko; I. Mereminskiy; S. Molkov; S. Sazonov; V. Arefiev
• Keywords: Vignetting

From October 2016 to September 2017, we performed tests of the ART-XC /SRG spare mirror system and detector unit at the 60-m-long IKI X-ray test facility. We describe some technical features of this test facility. We also present a brief description of the ART-XC mirror system and focal detectors. The nominal focal length of the ART-XC optics is 2700 mm. The field of view is determined by the combination of the mirror system and the detector unit and is equal to ∼0.31 square degrees. The declared operating energy range is 5–30 keV. During the tests, we illuminated the detector with a 55Fe+241 Am calibration source and also with a quasi-parallel X-ray beam. The calibration source is integrated into the detector’s collimator. The X-ray beam was generated by a set of Oxford Instruments X-ray tubes with Cr, Cu and Mo targets and an Amptek miniature X-ray tube (Mini-X) with Ag transmission target. The detector was exposed to the X-ray beam either directly or through the mirror system. We present the obtained results on the detector’s energy resolution, the muon on-ground background level and the energy dependence of the W90 value. The accuracy of a mathematical model of the ART-XC mirror system, based on ray-tracing simulations, proves to be within 3.5% in the main energy range of 4–20 keV and 5.4% in the “hard” energy range of 20–40 keV.