The NATALYA-2M spectrometer of high-energy radiations for the CORONAS-PHOTON space project

The NATALYA-2M high-energy radiation spectrometer is an element of the complex of scientific equipment of the CORONAS-PHOTON satellite. The instrument intended for registering gamma radiation of solar flares in the broad energy range of 0.2-1600 MeV as well as neutrons of solar origin with energies of 20-300 MeV represents itself as a scintillation spectrometer based on CsI(Tl) crystals with a total area of 32 x 38 cm(2) and the thickness of 18 cm. The spectra and time profiles of the gamma quanta count rates are measured in four subranges: R (0.2-2 MeV), L (1-18 MeV), M (7-250 MeV), and H (50-1600 MeV). Depending on the gamma radiation energy, the effective area of the instrument varies within the range from 750 to 900 cm(2), and the energy resolution at the Cs-137 line (662 keV) is 10%, it being about 30% at energies higher than 50 MeV. A system of stabilization based on the signal from the generator of reference light pulses is used to provide stability and automated adjustment of the parameters of spectrometric modules. The measuring channels of the instrument are calibrated during the flight using a source of tagged gamma quanta on the Co-60 radioactive isotope. Polystyrene scintillation counters are used to provide protection from the background of charged particles. The CORONAS-PHOTON spacecraft (SC) was launched from the Plesetsk spaceport on January 30, 2009, to a low circular near-Earth orbit (the altitude is 550 km, the inclination is 82.5A degrees). On February 27, the first scientific data were obtained from the NATALYA-2M instrument. The results of the flight calibration of the instrument detectors in different energy channels demonstrated good agreement with the ground measurements. The paper describes the instrument and observational potentials of the NATALYA-2M spectrometer, gives the results of the adjustment and calibration, and exemplifies the registration of gamma-ray bursts (GRBs)on the orbit.