The Chemical Composition and the Energy Spectrum of Heavy Nuclei in the Cosmic Radiation above 10 GeV/nucleon

A total of 7695 heavy nuclei were located in the Brawley emulsion stack. The error in energy estimation was about 30% and that in charge estimation was 0.25 units of charge for nuclei with z ≤9 and 0.5 for the iron group. The flux values for respective charge groups at the top of the atmosphere at energies above 10 GeV/nucleon are J M 0 =0.686±0.117, J H 0 =0.241±0.032, J LH 0 =0.166±0.022, J MH 0 =0.015±0.004 and J VH 0 =0.060±0.012, particles/m 2 ·sec·sterad. The integral energy spectra of the individual charge groups have the same exponent of γ=1.60 up to several hundreds of GeV/nucleon. On the basis of the experimental results in the present investigation, the mechanisms of cosmic ray acceleration and the amount of matter traversed by the cosmic rays are discussed.