Measurements of galactic cosmic-ray hydrogen and helium isotopes with the BESS-polar II instrument

Nicolas Picot-Clémente, K. Abe, H. Fuke, S. Haino, T. Hams, M. Hasegawa, A. Horikoshi, A. Itazaki, K. C. Kim, T. Kumazawa, A. Kusumoto, M. H. Lee, Y. Makida, S. Matsuda, Y. Matsukawa, K. Matsumoto, J. W. Mitchell, A. A. Moiseev, J. Nishimura, M. NozakiR. Orito, J. F. Ormes, K. Sakai, M. Sasaki, E. S. Seo, Y. Shikaze, R. Shinoda, R. E. Streitmatter, J. Suzuki, Y. Takasugi, K. Takeuchi, K. Tanaka, N. Thakur, T. Yamagami, A. Yamamoto, T. Yoshida, K. Yoshimura

Research output: Contribution to journalConference articlepeer-review


The Balloon-Borne Experiment with a Superconducting Spectrometer (BESS-Polar II) flew suc- cessfully over Antarctica for 24.5 days in December 2007 through January 2008 during a period of minimum solar activity. BESS-Polar II is concentrically arranged with various particle detectors and a solenoidal superconducting magnet that allow it to accurately identify hydrogen and helium isotopes among the incoming Galactic cosmic-ray nuclei. 2H and 3He are mostly secondary par- ticles produced after interaction of primary 1H and 4He cosmic rays during their propagation in the interstellar medium. The high mass separation of BESS-Polar II, the long-duration balloon flight and the stability of the instrument provide unprecedented high precision measurements of light isotopes. This paper will present new measurements of hydrogen and helium isotopes with energies from 0.2 GeV/nucleon up to about 1.5 GeV/nucleon, which gives essential information to better understand the history of cosmic-ray propagation in the Galaxy. They will be compared to previous results and theoretical calculations using GALPROP.

Original languageEnglish
Article number425
JournalProceedings of Science
Publication statusPublished - 2015
Externally publishedYes
Event34th International Cosmic Ray Conference, ICRC 2015 - The Hague, Netherlands
Duration: Jul 30 2015Aug 6 2015

ASJC Scopus subject areas

  • General


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