Precise measurements of cosmic-ray hydrogen and helium spectra with BESS

T. Sanuki*, H. Matsumoto, M. Nozaki, K. Abe, K. Anraku, Y. Asaoka, M. Fujikawa, M. Imori, T. Maeno, Y. Makida, N. Matsui, H. Matsunaga, J. Mitchell, T. Mitsui, A. Moiseev, M. Motoki, J. Nishimura, S. Orito, J. Ormes, T. SaekiM. Sasaki, E. S. Seo, Y. Shikaze, T. Sonoda, R. Streitmatter, J. Suzuki, K. Tanaka, I. Ueda, J. Z. Wang, N. Yajima, T. Yamagami, A. Yamamoto, T. Yoshida, K. Yoshimura

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


A series of Balloon-borne Experiments with a Superconducting Spectrometer, BESS, has been made since 1993. We report here the absolute cosmic-ray proton and helium spectra in energy ranges of 1 to 120 GeV and 1 to 54 GeV/nucleon, respectively, as measured by the 1998 balloon flight of the BESS spectrometer. Those spectra were determined within overall uncertainties of ±5 % for protons and ±10 % for helium nuclei including statistical and systematic errors. The covered energy range is relevant to the atmospheric neutrinos observed as "fully contained events" in Super-Kamiokande. In order to extend the energy range up to around 1 TeV, we have started to design and develop new tracking detectors. Those energy spectra in a higher energy region will help to estimate the interstellar spectra of primary cosmic rays and the absolute fluxes of "up-going muons."

Original languageEnglish
Pages (from-to)761-766
Number of pages6
JournalAdvances in Space Research
Issue number4
Publication statusPublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)


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