MEASUREMENTS OF COSMIC-RAY PROTON AND HELIUM SPECTRA FROM THE BESS-POLAR LONG-DURATION BALLOON FLIGHTS OVER ANTARCTICA

Journal Article · Tue May 10 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/822/2/65· OSTI ID:22663060

Abe, K.; Itazaki, A.; Kusumoto, A.; Matsukawa, Y.; Orito, R. ^[1]; Fuke, H. ^[2]; Haino, S.; Hasegawa, M.; Horikoshi, A.; Kumazawa, T.; Makida, Y.; Matsuda, S.; Matsumoto, K.; Nozaki, M. ^[3]; Hams, T.; Mitchell, J. W. ^[4]; Kim, K. C.; Lee, M. H.; Myers, Z. ^[5]; others, and

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1. Kobe University, Kobe, Hyogo 657-8501 (Japan)
2. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan)
3. High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan)
4. NASA-Goddard Space Flight Center (NASA-GSFC), Greenbelt, MD 20771 (United States)
5. IPST, University of Maryland, College Park, MD 20742 (United States)

The BESS-Polar Collaboration measured the energy spectra of cosmic-ray protons and helium during two long-duration balloon flights over Antarctica in 2004 December and 2007 December at substantially different levels of solar modulation. Proton and helium spectra probe the origin and propagation history of cosmic rays in the galaxy, and are essential to calculations of the expected spectra of cosmic-ray antiprotons, positrons, and electrons from interactions of primary cosmic-ray nuclei with the interstellar gas, and to calculations of atmospheric muons and neutrinos. We report absolute spectra at the top of the atmosphere for cosmic-ray protons in the kinetic energy range 0.2–160 GeV and helium nuclei in the range 0.15–80 GeV/nucleon. The corresponding magnetic-rigidity ranges are 0.6–160 GV for protons and 1.1–160 GV for helium. These spectra are compared to measurements from previous BESS flights and from ATIC-2, PAMELA, and AMS-02. We also report the ratio of the proton and helium fluxes from 1.1 to 160 GV and compare this to the ratios from PAMELA and AMS-02.

• OSTI ID: 22663060
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 822; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANTARCTICA
ANTIPROTONS
ATMOSPHERES
COMPARATIVE EVALUATIONS
COSMIC PROTONS
ENERGY SPECTRA
GALAXIES
GEV RANGE
HELIUM
INTERACTIONS
MAGNETIC RIGIDITY
MODULATION
MUONS
NEUTRINOS
POSITRONS
PRIMARY COSMIC RADIATION