Spectral calibration of filters and detectors of solar telescope at a wavelength of 13.2 nm for the TESIS project

The telescope at a wavelength of 13.2 nm of the TESIS device of the CORONAS-PHOTON satellite is intended for imaging hot plasma (T ～ 10 MK) of the solar corona. In this paper, calibration of optical elements of the telescope is described. The transmittance of multilayer Zr/Si filters and the sensitivity and radiation resistance of the CCD-array-based detector were measured. The transmittance of filters in the operating wavelength range was 40–50% (for filters of various thicknesses); the spectral dependence of the transmittance was close to the calculated one. The transmittance of filters in the visible region was (1–2) × 10^?6. The detector sensitivity was 0.01–0.1 analog-to-digital units per photon (adu/photon), the radiation resistance was better than 10⁹ rad.