Calibration of the ART-XC mirror modules at MSFC

• Published in: Experimental astronomy Vol. 44; no. 1; pp. 147 - 164
• Main Authors: Krivonos, R., Tkachenko, A., Burenin, R., Filippova, E., Lapshov, I., Mereminskiy, I., Molkov, S., Pavlinsky, M., Sazonov, S., Gubarev, M., Kolodziejczak, J., O’Dell, S. L., Swartz, D., Zavlin, Vyacheslav E., Ramsey, B. D.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2017; Springer Nature B.V
• Subjects: Angular resolution; Astronomy; CCD cameras; Chemistry and Earth Sciences; Computer Science; Concentrators; Defocusing; Diameters; Elliptic fitting; Flight tests; Focal plane; Morphology; Observations and Techniques; Original Article; Parameterization; Physics; Physics and Astronomy; Point spread functions; Space flight; Spacecraft; Spacecraft modules; Statistics for Engineering; Test procedures; Testing procedures; X ray mirrors; X ray telescopes; Instrumentation:X-ray optics; X-ray astrophysics
• ISSN: 0922-6435; 1572-9508
• DOI: 10.1007/s10686-017-9555-0

The Astronomical Röntgen Telescope X-ray Concentrator (ART-XC) is a hard X-ray telescope with energy response up to 30 keV, to be launched on board the Spectrum Röntgen Gamma (SRG) spacecraft in 2018. ART-XC consists of seven identical co-aligned mirror modules. Each mirror assembly is coupled with a CdTe double-sided strip (DSS) focal-plane detector. Eight X-ray mirror modules (seven flight and one spare units) for ART-XC were developed and fabricated at the Marshall Space Flight Center (MSFC), NASA, USA. We present results of testing procedures performed with an X-ray beam facility at MSFC to calibrate the point spread function (PSF) of the mirror modules. The shape of the PSF was measured with a high-resolution CCD camera installed in the focal plane with defocusing of 7 mm, as required by the ART-XC design. For each module, we performed a parametrization of the PSF at various angular distances Θ. We used a King function to approximate the radial profile of the near on-axis PSF (Θ < 9 arcmin) and an ellipse fitting procedure to describe the morphology of the far off-axis angular response (9 < Θ < 24 arcmin). We found a good agreement between the seven ART-XC flight mirror modules at the level of 10%. The on-axis angular resolution of the ART-XC optics varies between 27 and 33 arcsec (half-power diameter), except for the spare module.