The Primary Specific Ionization and Intensity of the Cosmic Radiation above the Atmosphere at the Geomagnetic Equator

Directional intensities and the primary specific ionization of the charged cosmic-ray flux above the atmosphere were measured by means of a G-M counter telescope in an Aerobee sounding rocket launched at the geomagnetic equator. The intensity at a zenith angle of 45° averaged over all azimuths, was found to be 0.04 particle ${\sec .\mathrm{}}^{-1\mathrm{}}$ ${\mathrm{cm}}^{-2\mathrm{}}$ ${\mathrm{steradian}}^{-1\mathrm{}}$, of which not more than 65 percent can be attributed to primaries, the remainder being due to albedo. The low value (∼40 percent) of the observed east-west asymmetry is most directly explainable in terms of positive proton primaries and a large albedo flux at large zenith angles, although a small contribution of negative primaries cannot be excluded.