[en] The balloon-borne Cosmic Ray Energetics And Mass experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here, we report results from the first two flights of ∼70 days, which indicate hardening of the elemental spectra above ∼200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at ∼10¹⁵ eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible explanations should also be investigated.

[en] 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.

[en] During its second Antarctic flight, the CREAM (Cosmic Ray Energetics And Mass) balloon experiment collected data for 28 days, measuring the charge and the energy of cosmic rays (CR) with a redundant system of particle identification and an imaging thin ionization calorimeter. Preliminary direct measurements of the absolute intensities of individual CR nuclei are reported in the elemental range from carbon to iron at very high energy.