| Project/Area Number |
13680619
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境影響評価(含放射線生物学)
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| Research Institution | University of Tsukuba |
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Principal Investigator |
SEKI Riki University of Tsukuba, Institute of Chemistry, Professor, 化学系, 教授 (70015775)
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| Co-Investigator(Kenkyū-buntansha) |
NAGASHIMA Yasuo University of Tsukuba, Institute of Basic Medical Sciences, Professor, 基礎医学系, 教授 (60091914)
古野 興平 筑波大学, 物理学系, 教授 (40015772)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
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| Keywords | Accelerator Mass Spectrometry / thermal neutron / ^<36>ClCl / shield concrete / DS02 / tandem Accelerator / タンデム加速 / タンデム加速器 / 塩素-36 / 中性子 / 広島原子爆弾 / DS86 / ^<36>C1 / ^<35>C1 / 環境放射能 / 中性子線量評価 |
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| Research Abstract |
Since long-lived radionuclide ^<36>Cl (half life : 30 x 10^4 y) produced by cosmic-ray in upper atmosphere emits only low energy β-ray, its radiation measurement in the environmental samples makes difficult. Recently, Accelerator Mass Spectrometry (AMS) has been developed in low level counting. In Accelerator Center, University of Tsukuba, ^<36>Cl measurement system by AMS has been constructed since 1999. In this study we tried to determine the neutron radiation dose by ^<36>Cl/Cl measurement using the AMS
1. Neutron radiation dose has been estimated by measuring ^<36>Cl/Cl in the irradiated soil samples by JCO accident. This result is agreed with estimation of neutron dose emitted from the Accident
2. Neutron radiation dose has been re-evaluated by measuring ^<36>Cl/Cl in the irradiated samples by atomic bomb dropped to Hiroshima. Granite samples quarried from tomb stones were collected in the known places of atomic bombed area and analyzed. The measured ^<36>Cl/Cl1 ratios were agreed with newly calculated radiation dose estimate system DS02
3. Neutron radiation dose has been estimated by measuring ^<36>Cl/Cl in the shielding concrete of various accelerator facilities. For three kinds of accelerator facilities, SF cyclotron (Center for Nuclear Study, The University of Tokyo), 300 MeV electron LINAC (Laboratory of Nuclear Science, Tohoku University) and 12GeV proton synchrotron (High Energy Accelerator Research, Organization), the depth profiles of ^<36>Cl/^<35>Cl ratios in concrete samples near the beam lines were analyzed
In the three cases mentioned above the neutron radiation dose were successfully estimated. The ratios of ^<36>Cl/Cl measured by AMS is a good tool to evaluate the neutron dose
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