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Study on the evaluation of fast-neutron energy spectrum of the Hiroshima atomic bomb

Research Project

Project/Area Number 11480125
Research Category

Grant-in-Aid for Scientific Research (B).

Allocation TypeSingle-year Grants
Section一般
Research Field Nuclear engineering
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

SHIBATA Seiichi  Kyoto University, Research Reactor Institute, Professor, 原子炉実験所, 教授 (80110708)

Co-Investigator(Kenkyū-buntansha) SHINOHARA Atsushi  Osaka University, Graduate School of Science, Professor, 理学部, 教授 (60183050)
TAKAMIYA Koichi  Kyoto University, Research Reactor Institute, Research Associate, 原子炉実験所, 助手 (70324712)
OHKUBO Yoshitaka  Kyoto University, Research Reactor Institute, Associate Professor, 原子炉実験所, 助教授 (70201374)
SHIBATA Tokushi  High Energy Accelerator Research Organization, Professor, 教授 (80028224)
SHIZUMA Kiyoshi  Hiroshima University, Department of Engineering, Professor, 工学部, 教授 (10127657)
高田 實彌  京都大学, 原子炉実験所, 助手 (10115868)
Project Period (FY) 1999 – 2000
Project Status Completed (Fiscal Year 2000)
Budget Amount *help
¥16,000,000 (Direct Cost: ¥16,000,000)
Fiscal Year 2000: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1999: ¥13,500,000 (Direct Cost: ¥13,500,000)
Keywordsatomic bomb / neutron / cross section / DS86 / ^<60>Co / ^<63>Ni / gamma-ray spectrometry / liquid scintillation counting
Research Abstract

The neutron spectra correlated to the distance from the hypocenter are given in the Dosimetry System 1986 (DS86). So far no experimental results for the fast neutrons have been reported for the Hiroshima atomic bomb except for the early measurement of ^<32>P.The detailed analysis of several nuclei produced by the thermal-neutron capture reaction suggests that the derived neutron spectrum for the Hiroshima atomic bomb is much harder than the spectrum given in DS86. The measurement of ^<152>Eu and ^<60>Co also suggests that systematic errors exist in the DS86 neutron spectrum. The recent measurements of ^<36>Cl for Hiroshima, Nagasaki and the reactor experiment have shown that the source neutrons for the Hiroshima atomic bomb could be different from the one given in DS86. Thus the direct measurement of the fast neutrons for the Hiroshima atomic bomb is particularly desirable.
In the present work, the reaction cross sections for ^<63>Cu(n, p)^<63>Ni were measured using the Dynamitron accelerator at the Fast Neutron Laboratory (FNL) of Tohoku University, which is indispensable as a basic nuclear data for the evaluation of neutron energy spectrum. After neutron irradiation, the ^<63>Ni was chemically separated by electrolysis, anion exchange and solvent extraction. The ^<63>Ni was determined by liquid scintillation counting. As a result, the fine structure in the excitation function was found, whose cause is investigated in the relation to the reaction mechanism. Also, ^<63>Ni was extracted from the Hiroshima copper samples by the same chemical procedure. The ^<63>Ni counting is still under way.

Report

(3 results)
  • 2000 Annual Research Report   Final Research Report Summary
  • 1999 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] S.Shibata et al.: "Measurement of excitation function for ^<63>Cu(n,p)^<63>Ni reaction up to E_n=15MeV"Czechoslovak Journal of Physics. Vol.49(S1). 843-846 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] M.Imamura,.,S.Shibata et al.: "^<252>Cf spectrum-averaged cross section for the ^<63>Cu(n,p)^<63>Ni reaction"Czechoslovak Journal of Physics. Vol.49(S1). 839-841 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Y.Ito,.,S.Shibata et al.: "A method to detect low-level ^<63>Ni activity for estimating fast neutron fluence from the Hiroshima atomic bomb"Health Physics. Vol.76(6). 635-638 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] S.Shibata et al.: "Measurement of excitation function for ^<63>Cu(n, p)^<63>Ni reaction up to E_n=15 MeV"Czechoslovak Journal of Physics. 49(S1). 843-846 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] M.Imamura, ., S.Shibata et al.: "^<252>Cf spectrum-averaged cross section for the ^<63>Cu(n, p)^<63>Ni reaction"Czechoslovak Journal of Physics. 49(S1). 839-841 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Y.Ito, ., S.Shibata et al.: "A method to detect low-level ^<63>Ni activity for estimating fast neutron fluence from the Hiroshima atomic bomb"Health Physics. 76(6). 635-638 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Y.Ito,S.Shibata et al.: "A method to detect low-level ^<63>Ni activity for estimating fast neutron fluence from the Hiroshima atomic bomb"Health Physics. Vol.76(6). 635-638 (1999)

    • Related Report
      2000 Annual Research Report
  • [Publications] S.Shibata et al.: "Measurement of excitation function for ^<63>Cu(n, p)^<63>Ni reaction up to En = 15MeV"Czechoslovak Journal of Physics. Vol.49,S1. 843-846 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] M.Imamura,S.Shibata et al.: "^<252>Cf spectrum-averaged cross section for the ^<63>Cu(n, p)^<63>Ni reaction"Czechoslovak Journal of Physics. Vol.49,S1. 839-841 (1999)

    • Related Report
      1999 Annual Research Report

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Published: 1999-04-01   Modified: 2016-04-21  

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