Energy spectra of cosmic-ray nuclei at high energies

H. S. Ahn, P. Allison, M. G. Bagliesi, L. Barbier, J. J. Beatty, G. Bigongiari, T. J. Brandt, J. T. Childers, N. B. Conklin, S. Coutu, M. A. Duvernois, O. Ganel, J. H. Han, J. A. Jeon, K. C. Kim, M. H. Lee, P. Maestro, A. Malinine, P. S. Marrocchesi, S. MinnickS. I. Mognet, S. W. Nam, S. Nutter, I. H. Park, N. H. Park, E. S. Seo, R. Sina, P. Walpole, J. Wu, J. Yang, Y. S. Yoon, R. Zei, S. Y. Zinn

Research output: Contribution to journalArticlepeer-review

208 Scopus citations


We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment Cosmic-Ray Energetics And Mass (CREAM). The instrument included different particle detectors to provide redundant charge identification and measure the energy of CRs up to several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg, Si, and Fe are presented up to 1014 eV. The spectral shape looks nearly the same for these primary elements and it can be fitted to an E -2.66 0.04 power law in energy. Moreover, a new measurement of the absolute intensity of nitrogen in the 100-800 GeV/n energy range with smaller errors than previous observations, clearly indicates a hardening of the spectrum at high energy. The relative abundance of N/O at the top of the atmosphere is measured to be 0.080 0.025 (stat.)0.025 (sys.) at 800 GeV/n, in good agreement with a recent result from the first CREAM flight.

Original languageEnglish (US)
Pages (from-to)593-603
Number of pages11
JournalAstrophysical Journal
Issue number1
StatePublished - 2009

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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