ИСТИНА

In frame of the Moscow University space program, several nanosatellites will be launched in 2023 into sun-synchronous orbit. Among them the Avion satellite, made in the cubesat-6U standard, and a number of similar Monitor satellites in the cubesat-3U standard are being prepared. All these satellites will be equipped with scientific and educational payload – one or several instruments DeCoR, designed to study the temporal and spectral characteristics of electrons and gamma radiation. The subject of the study will be cosmic gamma-ray bursts, solar flares, electron precipitation, and the variations of particle fluxes connected with solar activity. The instruments DeCoR are scintillation spectrometers, similar to the DeCoR devices operating on the VDNH-80, Norby, and several others cubesats, designed to study variations of near-Earth electron fluxes. The detection element is a combination of 3 mm thick plastic scintillator and 10 mm thick CsI(Tl) crystal. The detectors installed on the satellites to be launched in 2023 differ in sensitive area optimized for individual scientific task. All upcoming satellites will have the DeCoR-2 device, optimized for the detection and study of cosmic gamma-ray bursts of various nature. This instrument has an effective area increased up to 65 cm2, which is necessary both to improve the sensitivity and to improve the time resolution, which is determined primarily by the statistics of detected gamma-quanta. A composite scintillation detector consisting of a 3 mm plastic scintillator and a 9 mm CsI (Tl), viewed by a silicon photomultiplier assembly (SiPM), provides separate detection of gamma radiation and electrons in the energy release range from 20 keV to 1 MeV. It is important when conducting the experiment for GRB study in polar orbit. The 6U cubesat Avion will be equipped with a set of 3 different DeCoR devices. Except for DeCoR-2 instrument described above the DeCoR-1 spectrometer with 18 cm2 scintillatorsviewed by two ordinary PMTs is placed to study electron flux variations in energy release range of 50 keV to 2 MeV. The DeCoR-3 device is added to extend the range of detected gamma radiation to the high-energy region up to 5 MeV. Its main goal is to measure the gamma-ray spectra of solar flares and cosmic gamma-ray bursts. The detecting element of this node is a 30x30x30 mm3 CsI(Tl) scintillation crystal. Data from each DeCoR device are recorded both in the form of monitoring (counting rate in several channels) and in the form of detailed event-by-event record. The data are stored in energy independent memory of the payload as well as in the memory of on-board computer, so one can select the most important data sections for transmission to the Earth in primary form taking into account the data transfer limit. The daily amount of scientific data is about 1 Mb from each of the Monitor satellites and about 100 MB from the DeCoR complex of Avion satellite.