1993 Fiscal Year Final Research Report Summary
Observation of Cosmic Rays by using a Balloon-Borne Superconducting Magnet Spectrometer
| Project/Area Number |
02402004
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | Kobe University (1992-1993)
The University of Tokyo (1990-1991) |
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Principal Investigator |
NOZAKI Mitsuaki Kobe University, Faculty of Science, Department of Physics, Assistant Professor, 理学部, 助教授 (10156193)
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| Co-Investigator(Kenkyū-buntansha) |
IMORI Masatoshi University of Tokyo International Center for Elementary Particle Physics Researc, 素粒子物理国際研究センター, 助手 (70011690)
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| Project Period (FY) |
1990 – 1993
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| Keywords | cosmic rays / anti-proton / anti-heliums / magnet spectrometer |
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| Research Abstract |
The BESS experiment (Balloon-borne Experiment using a Superconducting magnet Spectrometer) was planned and the BESS detector was developed to investigate an origin of cosmic ray anti-particles such as anti-protons and anti-helium nuclei. The spectrum of secondary anti-protons are extremely low below 1 GeV due to the kinematical suppression. On the other hand, the anti-protons expected from the hypothetical sources such as the annihilation of neutralino dark matter particles or the evaporation of primordial black holes give rather flat spectrum. Therefore low energy anti-protons are sensitive to those exotic origins.
The detector system consisted of a thin superconducting solenoidal magnet, a cylindrical jet-drift chamber, 4 layrs of arc-shaped drift chambers and time-of-flight counters. The cylindrical configuration of the BESS detector provided a wide tracking volume and a large geometrical acceptance.
The balloon flight of the BESS was carried out at Lynn Lake, Canada, in July 1993. The instrument flew at an altitude of 36.5 km for 14 hours. A total of 4 million events were recorded during the flight.
We detected 4 anti-protons including 0.4 events of beckground at energies below 500 MeV.This was the first positive measurement of the low energy anti-protons. The ratio of anti-proton flux to proton was calculated and it was found to be consistent with the model of the secondary production, though the model has still large uncertainties.
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[Publications] M.Imori, K.Anraku, S.Inaba, I.Ueda, T.Saeki, T.Haga, T.Tsunoda, M.Nozaki, T.Yamagami, T.Yoshida, and K.Yoshimura: "Real-Time Data Processes in a Ballon-Borne Apparatus" IEEE Trans.Nucl.Sci.Vol.39. 1389-1393 (1992)
Description
「研究成果報告書概要(欧文)」より
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[Publications] M.Imori, K.Yoshimura, I.Ueda, T.Yoshida, K.Anraku, S.Inaba, T.Saeki, H.Honda, H.Matsunaga, M.Motoki, M.Nozaki, N.Takimi, and T.Yamagami: "A Remote Console System for Balloon Borne Experiments" IEEE Trans.Nucl.Sci.Vol.40. 913-916 (1993)
Description
「研究成果報告書概要(欧文)」より
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[Publications] K.Anraku, R.Golden, T.Haga, Y.Higashi, M.Imori, S.Inaba, B.Kimbell, N.Kimura, Y.Makida, H.Matsumoto, H.Matsunaga, M.Motoki, J.Nishimura, M.Nozaki, S.Orito, T.Saeki, J.Suzuki, N.Takimi, K.Tanaka, I.Ueda, N.Yajima, T.Yamagami, A.Yamamoto, T.Yoshida, and K.Yoshimura: "Balloon-borne Experiment with a Superconducting Solenoidal Magnet Spectrometer" Adv.Space Res.Vol.14. 75-87 (1994)
Description
「研究成果報告書概要(欧文)」より
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[Publications] K.Yoshimura, S.Orito, I.Ueda, K.Anraku, R.L.Golden, M.Imori, S.Inaba, B.Kimbell, N.Kimura, Y.Makida, H.Matsumoto, H.Matsunaga, J.Mitchell, M.Motoki, J.Nishimura, M.Nozaki, J.Ormes, T.Saeki, R.Streitmatter, J.Suzuki, K.Tanaka, N.Yajima, T.Yamagami, A.Yamamoto, and T.Yoshida: "Observation of Cosmic-Ray Antiprotons at Energies below 500 MeV" KEK Preprint 94-202 UT-ICEPP 95-02 KOBE-HEP 95-02 submitted to Phys.Rev.Lett.
Description
「研究成果報告書概要(欧文)」より
