Energy spectrum of secondary protons above the atmosphere measured by the instruments NINA and NINA-2

In this paper we report on the energy spectrum of protons of albedo origin measured by the instruments NINA and NINA-2 at different geomagnetic locations, and the behaviour of the proton flux as a function of altitude out of the South Atlantic Anomaly. The instrument NINA was used on board the satellite Resurs-01-N4 between 1998 and 1999, at an altitude of about 830km. The NINA-2 apparatus, on board the satellite MITA, was put into orbit in July 2000, at an altitude of about 450 km. A detailed understanding of the fluxes of charged particles in near Earth orbit is important to reach an accurate theoretical description of the Earth's magnetic field, but also as input for the calculation of the background for scientific instruments aboard satellites, like the future AGILE and GLAST gamma astronomy telescopes.