Elemental abundance of high energy cosmic rays
Very high energy spectra of cosmic ray nuclei from the JACEE balloon experiments are presented. From a total of 12 balloon flights with an exposure factor of about 580 m2hour the energy spectra of nuclei have been obtained in the energy range from several TeV to 1,000 TeV. Proton energy spectrum, extending to several hundred TeV, can be a single-power law. Helium shows a single power law spectrum in the energy range from 2 TeV/n to 200 TeV/n. Other nuclei up to Fe indicated harder spectral indices compared with those of protons and helium. The composition at around 500 TeV is 16 ± 5%: 29 ± 5%: 35 ± 5%: 9 ± 3%: 11 ± 4%, for the abundance of p : He : C ∼ O : Ne ∼ S : Z ≥ 18.