Measurements of cosmic-ray electron and gamma-ray flux with balloon-borne CALET prototype

T. Niita*, S. Torii, K. Kasahara, T. Tamura, K. Yoshida, Y. Katayose, H. Murakami, S. Ozawa, Y. Shimizu, Y. Akaike, Y. Ueyama, D. Ito, M. Karube, K. Kondo, M. Kyutan

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

2 Citations (Scopus)


We carried out the balloon experiments using CALET (CALorimetric Electron Telescope) prototype detectors in May 2006 (bCALET-1) and August 2009 (bCALET-2) for verification of both the detector performance and the capability of measuring the cosmic rays at higher atmosphere. The bCALET-2 instrument for observing the electrons and the gamma rays at energies in 1-100 GeV is composed of an imaging calorimeter consisting of 4096 scintillating fibers with a total of 3.6 radiation lengths of tungsten plates, and a total absorption calorimeter consisting of crossed 60 BGO logs with a total of 13.4 radiation lengths depth. The bCALET-2 was launched from the Taiki Aerospace Research Field, Japan Aerospace Exploration Agency, in Hokkaido, and flew successfully for 2.5 hours at a level altitude of 35 km. In this paper, we will present the spectra of electrons and gamma rays in the energy range of 1-100 GeV measured by bCALET-2, comparing with our previous observations, bCALET-1 and BETS. The detector performance is studied by comparing with the simulations, and the observed fluxes are found to be compatible with the expected.

Original languageEnglish
Number of pages4
Publication statusPublished - 2011
Event32nd International Cosmic Ray Conference, ICRC 2011 - Beijing, China
Duration: 2011 Aug 112011 Aug 18


Conference32nd International Cosmic Ray Conference, ICRC 2011


  • Atmospheric gamma-rays
  • Balloon experiment
  • Direct measurement
  • Electrons

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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