7th ISF

PHYS019 - Research of Gamma Radiation Level and Charged Particles in a Sun-Synchronous Orbit

In a low Earth orbit (LEO), spacecraft are exposed to gamma-rays, charged particles (protons and electrons) of solar, galactic and extragalactic origin, and charged particles trapped in the Earth's magnetosphere (Van Allen belts). The study of spatial distribution and time variations of the Van Allen belt particle fluxes is important for spacecraft hardware development and planning of astrophysical observations from low Earth orbit. We present the analysis of radiation environment at the ~550 km Sun-synchronous orbit using the data of “Konus-RF” sodium iodide scintillation gamma-ray spectrometer developed at the Ioffe Institute, St Petersburg and mounted on the “Koronas-Foton” space observatory operated in 2009. In particular, we have developed a data visualization tool and algorithm for searching time intervals unaffected by the radiation belts. By means of these tools, we have estimated the fraction of time suitable for astrophysical observations, e. g., detection of gamma-ray bursts, and the location of the radiation belts in the orbit. Finally, we compare our results with the models of Earth's magnetosphere electron and proton fluxes. We also discuss possible applications of these for planning new instruments for gamma-ray astronomy.

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