Cosmic-Ray Proton and Helium Spectra From the First Cream Flight

Abstract

Cosmic-ray proton and helium spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass experiment flown for 42 days in Antarctica in the 2004-2005 austral summer season. High-energy cosmic-ray data were collected at an average altitude of ∼38.5 km with an average atmospheric overburden of ∼3.9 g cm −2 . Individual elements are clearly separated with a charge resolution of ∼0.15 e (in charge units) and ∼0.2 e for protons and helium nuclei, respectively. The measured spectra at the top of the atmosphere are represented by power laws with a spectral index of −2.66 ± 0.02 for protons from 2.5 TeV to 250 TeV and -2.58 ± 0.02 for helium nuclei from 630 GeV nucleon −1 to 63 TeV nucleon −1 . They are harder than previous measurements

Cosmic ray physics with ARGO-YBJ

“…Results from PAMELA [13], CREAM [14] and the models by Hörandel [15] and Gaisser, Stanev and Tilav [16] are also shown.…”

“…A clear knee structure is observed around 700 TeV. The p+He spectra by CREAM [14], ARGO-YBJ [6] and the hybrid experiment [20] below the knee, the spectra by Tibet AS [21] and KASCADE [22] above the knee are shown for comparison. In our result, the error bar is the statistical error, and the shaded area represents the systematic uncertainty [23] for details).…”

Introduction to the High Energy cosmic-Radiation Detection (HERD) Facility onboard China’s Future Space Station

“…4, we show the predicted HERD spectra for protons, helium nuclei, carbon nuclei and iron nuclei, in comparison with all previous direct measurements in space. Clearly HERD will surpass all previous results of directly measured cosmic rays from, e.g., AMS02 [13], ATIC-2 [14], BESS [15], CREAM, [16,17] HEAO [18], JACEE [19], PAMELA [20], RUNJOB [21], SOKOL [22] and TRACER [23], with much better statistics and up to much higher energies even beyond PeV and into the "knee" region. For example, at least ten events will be recorded from 900 TeV to 2 PeV for each specie, which means that the expected energy spectra of most nuclei will be directly extended to the knee range with much smaller error bars than previous direct measurements in space.…”

“…Ground-based extensive air shower experiments [6,7,8] continue to make progress [9]; however, these experiments have difficulties in making composition-resolved high-energy resolution measurements of the fine structure of the "knee". On the other hand, experiments based on balloons [14,16], satellites [20], or the international space station [13] can measure the particle energy and charge directly; however, these experiments suffer from small geometrical factor and limited energy range to make statistically meaningful measurements of the "knee".…”

A possible origin of gamma rays from the Fermi Bubbles

“…This form of source spectrum is chosen so as to reproduce the recently measured proton spectrum by various experiments such as the ATIC [22], CREAM [23], and PAMELA, [24] which exhibit a spectral hardening above ∼ 250 GeV. The observed hardening might be due to the effect of local sources, propagation effects or signature of the cosmicray source spectrum itself (see e.g., Refs.…”