New measurement of the electron flux from 10 gev to 100 gev with the bets instrument

Shoji Torii*, T. Tamura, N. Tateyama, K. Yoshida, T. Yamagami, E. Kamioka, Y. Saito, H. Murakami, T. Kobayashi, Y. Komori, K. Kasahara, T. Yuda, J. Nishimura

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The BETS (balloon-borne electron telescope with scintillating fibers) instrument has been developed for high-altitude balloon flights to observe the cosmic ray electrons with energies of 10 GeV to several 100 GeV. The detector is a Lead/SciFi sampling calorimeter consisting of 36 SciFi belts (each 280 mm wide) and 8 lead plates (each 5 mm thick). The electron identification is performed by triggering the electro-magnetic showers on board and by analyzing the three-dimensional shower images by an intensified CCD camera. It is demonstrated in the flight data in 1995 and 1997 that a reliable identification of the electron component against the proton background is achieved up to a few 100 GeV. The performance of detector was tested by the CERN-SPS electron beams in 1996 and with the proton beams in 1997. The obtained energy spectrum is consistent with the recent observation by HEAT, although our result still has a little room for improvement. The energy spectrum from 10 GeV to 1000 GeV which is obtained by combining these data and the emulsion chamber data ( Nishimura et al. 1997) suggests that the diffusion constant is about 1 × 1028 (E/GeV)0.3 cm2/sec in the energy range between 10 GeV and 1000 GeV. A hump in the energy spectrum is observed around several hundred GeV, which is expected from a nearby source.

Original languageEnglish
Pages (from-to)1823-1826
Number of pages4
JournalAdvances in Space Research
Issue number11
Publication statusPublished - 2000 Dec
Externally publishedYes

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics


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