Superconducting solenoidal spectrometer for a balloon-borne experiment

Y. Ajima, K. Anraku, T. Haga, Y. Higashi, H. Honda, M. Imori, S. Inaba, N. Kimura, M. Kobayashi, Y. Makida, N. Matsui, H. Matsumoto, H. Matsunaga, M. Motoki, M. Nozaki, Y. Nishihara, J. Nishimura, S. Orito, M. Otoba, T. SaekiT. Sanuki, M. Sasaki, K. Shimamura, J. Suzuki, K. Suzuki, N. Takimi, K. Tanaka, T. Tsunoda, I. Ueda, T. Yajima, T. Yamagami, A. Yamamoto, H. Yamaoka, T. Yoshida, K. Yoshimura

Research output: Contribution to journalArticlepeer-review

70 Citations (Scopus)


The BESS detector is a new type of balloon-borne spectrometer which utilizes various technologies recently developed for collider experiments. The principal scientific objectives include a measurement of cosmic-ray antiproton spectrum, search for anti-nuclei in cosmic radiation, and precise measurements of cosmic-ray primaries. A thin superconducting solenoidal coil produces a uniform magnetic field of 1 T. Cylindrical drift chambers are located inside and outside the coil and perform continuous tracking. The momentum resolution is 0.5% at 1 GeV/c. i.e., the maximum detectable rigidity is 200 GV. Scintillation counter hodoscopes, placed above and below the solenoid, provide timing and dE/dx measurements and trigger generation. The timing resolution is 80 ps/counter. This cylindrical configuration achieves a large geometrical acceptance of 0.35 m2 sr which is essential to detect rare cosmic-ray particles. In order to cope with high trigger rate and large data size, intelligent trigger circuits and a fast and parallel data acquision system are also developed. In 1993, the first scientific flight of the BESS apparatus was carried out and the first mass-measured antiprotons were detected at energies below 500 MeV.

Original languageEnglish
Pages (from-to)71-100
Number of pages30
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1
Publication statusPublished - Mar 21 2000
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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