The energy spectrum of primary cosmic rays above 1012eV

Abstract

Recent direct experimental measurements of the primary proton spectrum have given a power law with differential slope gamma _d approximately -2.75 for energy less than about 10¹² eV. Extrapolation of this spectrum gives intensities of the order of those derived from extensive air showers in the region of 10¹⁸-10¹⁹ eV. The data from a variety of experiments which had previously indicated intensities significantly above this spectrum, particularly in the range 10¹⁴-10¹⁶ eV, are re-examined critically. It is concluded that the intensities are indeed higher and that a single exponent is quite inadequate to describe the spectral range 10¹⁰-10²⁰ eV.