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

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


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