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2004 Fiscal Year Final Research Report Summary

Study of High-energy Cosmic Gamma Rays and Cosmic Rays in Tibet.

Research Project

Project/Area Number 14340070
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 素粒子・核・宇宙線
Research InstitutionThe University of Tokyo (2003-2004)
Nagoya University (2002)

Principal Investigator

YUDA Toshinori  The University of Tokyo, Institute for Cosmic Ray Research, Professor Emeritus, 宇宙線研究所, 名誉教授 (60092368)

Co-Investigator(Kenkyū-buntansha) TAKITA Masato  The University of Tokyo, Institute for Cosmic Ray Research, Associate Professor, 宇宙線研究所, 助教授 (20202161)
OHNISHI Munehiro  The University of Tokyo, Institute for Cosmic Ray Research, Research Associate, 宇宙線研究所, 助手 (10260514)
YAMAMOTO Yoshiaki  Konan University, Faculty of Science and Technology, Professor, 理工学部, 教授 (70068112)
HOTTA Naoki  Utsunomiya University, Faculty of Education, Professor, 教育学部, 教授 (60157039)
Project Period (FY) 2002 – 2004
KeywordsTibet / air shower array / knee energy region / emulsion chamber / burst detector / cosmic-ray acceleration / cosmic-ray anisotropy / supernova remnant
Research Abstract

We study high-energy cosmic gamma rays and cosmic rays with an air shower array (Tibet-II and Tibet-III) in Tibet as a joint research with China. The main research purpose is to study the origin and acceleration mechanism of high-energy cosmic rays by the observation of high-energy primary cosmic-ray energy spectrum and by observation/search of celestial high-energy cosmic gamma-ray point sources
From 1996 to 1999, we set up 80 m^2 emulsion chambers and burst detectors at the center of Tibet-II and studied the energy spectrum of primary cosmic-ray protons in the knee energy region. We obtained the energy spectrum of protons above 10^<15> eV for the first time in the world, by analyzing the emulsion chamber data. The measured energy spectrum showed steepening of the spectral index in the power-law spectrum compared with that below 10^<14> eV, suggesting the acceleration scenario of cosmic rays in the shock wave in a supernova remnant. For this pupose, we developed an automatic analysis device of X-ray films based on a commercial image scanner which enabled us to process X-ray film data. We also did R&D studies of a burst detector array (1000 m^2) for selectively detecting heavy nuclei in the knee energy region, in cooperation with Tibet-III. Four test detectors with a plastic scintillator and optical fibers were setup and in operation in the Tibet-III.
We also successfully observed the energy dependence of the apparent anisotropy in multi-TeV galactic cosmic-ray intensitiy due to the terrestrial orbital motion around the Sun for the first time in the world. We obtained a new result on the cosmic-ray anisotropy at the sidereal time frame as well.

  • Research Products

    (11 results)

All 2005 2004 2003 2002 Other

All Journal Article (11 results)

  • [Journal Article] Large-scale sidereal anisotropy of Galactic cosmic ray intensity observed by the Tibet air shower array2005

    • Author(s)
      M.Amenomori et al.
    • Journal Title

      The Astrophysical Journal Letters (in press)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Observation by an air-shower array in Tibet of multi-TeV cosmic-ray anisotropy due to terrestrial orbital motion around the Sun2004

    • Author(s)
      M.Amenomori et al.
    • Journal Title

      Physical Review Letters 94・6

      Pages: 061101-1-061101-4

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Automatic analysis of the emulsion chamber using the image scanner applied to the Tibet hybrid experiment2004

    • Author(s)
      S.Ozawa et al.
    • Journal Title

      Nuclear Instruments and Methods in Physics Research A523

      Pages: 193-205

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Observation by an air-shower array in Tibet of multi-TeV cosmic ray anisotropy due to terrestrial orbital motion around the Sun2004

    • Author(s)
      M.Amenomori et al.
    • Journal Title

      Physical Review Letters 94-6

      Pages: 061101-1-061101-4

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Primary proton spectrum in the knee region observed by the Tibet hybrid experiment2003

    • Author(s)
      M.Amenomori et al.
    • Journal Title

      Proceedings of the 28^<th> International Cosmic Ray Conference, Tsukuba,2003 1

      Pages: 107-110

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] An experiment to measure the spectra of primary proton, helium and iron nuclei at the ‘knee' region at a high altitude2003

    • Author(s)
      X.W Xu et al.
    • Journal Title

      Journal of Physics G : Nuclear and Particle Physics 29

      Pages: 719-735

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Primary proton spectrum in the knee region observed by the Tibet hybrid experiment2003

    • Author(s)
      M.Amenomori et al.
    • Journal Title

      Proceedings of the 28^<th> International Cosmic Ray Conference, Tsukuba, 2003 1

      Pages: 107-110

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] An experiment to measure the spectra of primay proton, helium and iron nuclei at the 'knee' region at a high altitude2003

    • Author(s)
      X.W Xu et al.
    • Journal Title

      Journal of Physics G : Nuclear and Particle Physics 29

      Pages: 719-735

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Primary proton spectrum around the knee deduced from the emulsion chamber data obtained at Mts Fuji and Kanbala2002

    • Author(s)
      J.Huang et al.
    • Journal Title

      Astroparticle Physics 18

      Pages: 637-648

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Primary proton spectrum around the knee deduced from the emulsion chamber data obtained at Mts Fuji and Kanbala2002

    • Author(s)
      J.Hwang et al.
    • Journal Title

      Astroparticle Physics 18

      Pages: 637-648

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Large-scale sidereal anisotropy of Galactic cosmic ray intensitiy observed by the Tibet air shower array

    • Author(s)
      M.Amenomori et al.
    • Journal Title

      The Astrophysical Journal Letters (in press)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2006-07-11  

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