| Project/Area Number |
09680527
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
UEHARA Shuzo Kyushu University, School of Health Sciences, Professor, 医療技術短期大学部, 教授 (90038927)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Radiation action / Biophysical modelling / Electron track structure / Monte Carlo simulation / Cross-section data / Frequency of interaction / Point kernel / 吸収線量分布 |
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| Research Abstract |
1) The purpose of this study is to make an intercomparison and assessment of cross sections for water used in electron track structure codes. This study is intended to shed light on to what extend the differences between the input data and physical and chemical assumptions influence the outcome in biophysical modelling of radiation effects.
2) lonisation cross sections and spectra of secondary electrons were calculated by various theories. The analyses were carried out for water vapor cross sections as these are more abundant and readily available. All suitably published experimental total ionization cross sections were fitted by an appropriate function and used for generation of electron tracks. Three sets of compiled data were used for comparison of total excitation cross sections and mean excitation energy.
3) The tracks generated by a Monte Carlo track code, using various combinations of cross sections, were compared in terms of radial distributions of interactions and point kernels. The spectrum of secondary electrons emitted by the ionization process was found to be the most influential factor on these quantities. A different set of cross sections for excitation and elastic scattering did not affect the electron track structure as much as did ionization cross sections. It is concluded that all codes, using different cross sections and in different phase, currently used for biophysical modelling exhibit close similarities in larger size targets while appreciable differences are observed at DNA size targets.
4) We recommend fitted functions to all available suitable experimental data for the total ionization and elastic cross sections. We conclude that most codes produce tracks in reasonable agreement with the macroscopic quantities such as total stopping power and total yield of strand breaks. However, we predict differences in frequencies of clustering in track.
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