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2000 Fiscal Year Final Research Report Summary

Study on the light breaching effect on positron annihilation

Research Project

Project/Area Number 11640517
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Physical chemistry
Research InstitutionHigh Energy Accelerator Research Organization

Principal Investigator

KONDO Kenjiro  Applied Research Laboratory, High Energy Accelerator Research Organization, Professor, 共通研究施設, 教授 (20004434)

Co-Investigator(Kenkyū-buntansha) OKI Yuichi  Radiation Science Center, High Energy Accelerator Research Organization, Research Associate, 放射線科学センター, 助手 (40204094)
MIURA Taichi  Radiation Science Center, High Energy Accelerator Research Organization, Research Associate, 放射線科学センター, 助手 (80209717)
SUZUKI Takenori  Radiation Science Center, High Energy Accelerator Research Organization, Professor, 放射線科学センター, 教授 (40162961)
NUMAJIRI Masaharu  Radiation Science Center, High Energy Accelerator Research Organization, Research Associate, 放射線科学センター, 助手 (20189385)
Project Period (FY) 1999 – 2000
Keywordspositron annihilation / trapped electron / low temperature / freezing of movement / polymer / free volume / light breaching / positronium
Research Abstract

The positron-irradiation effect has been studied and increases and decreases in the positronium (Ps) formation have been reported at low and room temperature, respectively. Before observing positronium (Ps) quenching by irradiating polymer samples with visible light, the increase at low temperature was explained by the relaxation behavior of polymer structures. A quenching experiment has demonstrated that Ps formation is accelerated by an increase in the trapped electrons, which are induced by the ionization of injected positrons and trapped in a shallow potential being formed among polymer structures at low temperature. This is a similar phenomenon to the well-known "anti-inhibition or anti-recombination effect"
The decrease in I_3 at room temperature has been explained by many ideas, such as cross-links, structure change, and radicals. A structure change and the cross-links were introduced to explain the decrease in I_3 at low gamma-irradiation doses of around 10 kGy, since, at a low … More irradiation dose, it seems to be difficult to expect radicals which affect the change of I_3.
Although positron annihilation lifetime spectroscopy (PALS) is a useful method for studying the characteristics of polymers, all factors, which affect Ps formation, must be paid attention to in order to understand the result. From this point of view, the complicated feature of I_3 is worth to be investigated and the study may have a potential to increase the validity of PALS as the analytical method of polymers.
In this research, the radiation effect induced in samples by positrons has been discussed. Positrons are supplied as a probe from positron sources and at the same time induce radiation effect in the samples. From this point of view PA is not an un-destructive method for polymer. It has been shown that, using the idea of trapped electrons, relaxation process of polymer structures can be investigated by PALS as a secondary effect of the disappearance of the shallow potential due to the thermal molecular motion. Less

  • Research Products

    (16 results)

All Other

All Publications (16 results)

  • [Publications] 濱田栄作、近藤健次郎、他: "Development of a Pulsed Slow-Positron Beam Using Time-Varying Pulsing-Bias"Applied Surface Science. 149. 40-43 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 伊藤寛、鈴木健訓、他: "The efect of visible light irradiation on positronium formation in polyethylene at low temperature"ACTA PHYSICA POLONICA A. 95. 533-538 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 鈴木健訓、近藤健次郎、他: "Radiation effect on positronium formation in low temperature polyethylenes"Radiation Physics and Chemistry. 58. 485-489 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 濱田栄作、近藤健次郎、他: "Application of pulsed slow positron beam to polymer"Radiation Physics and Chemistry. 58. 771-775 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 伊藤泰男、鈴木健訓: "An application of the coincidence Doppler spectroscopy for substances of chemical interest"Radiation Physics and Chemistry. 58. 743-747 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Goworek,近藤健次郎、他: "Pressure quenching of positronium in solid biphenyl"Chemical Physics. 255. 347-351 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Goworek, T.Suzuki, E.Hamada, K.Kondo, Y.Ito: "Pressure quenching of positronium in solid biphenyl"Chemical Physics. 255. 347-351 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ito Y.and Suzuki T.: "An application of the coincidence Doppler spectroscopy for substances of chemical interest"Rad. Phys. Chem.. vol. 58. 743-747 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hamada E., Ohshima N., Suzuki T., Kobayashi H., Kondo K., Kanazawa I., and Ito Y: "Application of pulsed slow positron beam to polymer"Rad. Phys. Chem.. vol. 58. 771-775 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Kansy J., Suzuki T., Ogawa T., and Murakami M.: "Study of poly(methylphenylsilylenemethylene) by elastic thermalization lifetime analysis"Rad. Phys. Chem.. vol. 58. 545-550 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Suzuki T., Kondo K., Ito Y., Hamada E., and Ito Y.: "Radiation effect on positronium formation in low temperature polyethylenes"Rad. Phys. Chem.. vol. 58. 485-489 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ito Y., Hirade T., Hamada E., Suzuki T., and Ito Y.: "The effect of visible light irradiation on positronium formation in polyethylene at low temperature"ACTA PHYSICA POLONICA A. 95. 533-538 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Suzuki T., Hayashi T., and Ito Y.: "Polymerization of Epoxy Resins Studied by Positron Annihilation"ACTA PHYSICA PALONICA A. 95. 671-676 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hamada E., Oshima N., Suzuki T., Kobayashi H., Kondo K., Kanazawa I, and Ito Y.: "Development of a Pulsed Slow-Positron Beam Using Time-Varying Pulsing-Bias"Applied Surface Science. 149. 40-43 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hayashi T., Nakamura H.and Suzuki T.: "Characterization of curing behavior of cyanic ester by a positron-annihilation lifetime technique"Polymer. vol. 40. 1053-1056 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Oshima N., Hamada E., Suzuki T., Kanazawa I.and Ito Y.: " Application of Pulsed Slow-Positron Beam to Polymer"Journal of Radioanalytical and Nuclear Chemistry. Vol. 239. 329-333 (1999)

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      「研究成果報告書概要(欧文)」より

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Published: 2002-03-26  

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