Precise Measurement of Cosmic-Ray Proton and Helium Spectra with the BESS Spectrometer

/ Authors

T. Sanuki, M. Motoki, M. Motoki, H. Matsumoto, E. Seo, J. Z. Wang, K. Abe, K. Anraku, Y. Asaoka, M. Fujikawa

and 27 more authors

M. Imori, T. Maeno, Y. Makida, N. Matsui, H. Matsunaga, H. Matsunaga, J. Mitchell, T. Mitsui, T. Mitsui, A. Moiseev, J. Nishimura, M. Nozaki, S. Orito, J. Ormes, T. Saeki, M. Sasaki, Y. Shikaze, T. Sonoda, R. Streitmatter, Jun-ichi Suzuki, Kenichi Tanaka, I. Ueda, N. Yajima, T. Yamagami, A. Yamamoto, T. Yoshida, K. Yoshimura

/ Abstract

We report cosmic-ray proton and helium spectra in energy ranges of 1-120 GeV nucleon-1 and 1-54 GeV nucleon-1, respectively, measured by a flight of the Balloon-borne Experiment with Superconducting Spectrometer (BESS) in 1998. The magnetic rigidity of the cosmic ray was reliably determined by highly precise measurement of the circular track in a uniform solenoidal magnetic field of 1 T. Those spectra were determined within overall uncertainties of ±5% for protons and ±10% for helium nuclei including statistical and systematic errors.

Journal: The Astrophysical Journal

DOI: 10.1086/317873