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

We have performed calibration tests of a spare CdTe detector unit of the ART-XC/SRG telescope at the Space Research Institute’s 60-m-long X-ray test facility. During the tests, we illuminated the detector with a quasi-parallel X-ray beam generated by interchangeable X-ray tubes with different targets. To monitor the X-ray flux, we used two commercial detectors Amptek XR-100T-CdTe and XR-100SDD. We present some features of the ART-XC detectors operation, limitations of reducing the lower energy thresholds for photon detection and results of verification of the detector’s flat field characteristics at different energies. We estimate the ART-XC X-ray detector efficiency based on data obtained by the Amptek detectors and the ratio of their model efficiency. Using the measured detector efficiency, we have updated the ART-XC telescope’s on-axis effective area for the sum of doubly and singly reflected events. The ART-XC effective area reaches a maximum of 410 ± 16 cm2 at 9.6 keV.