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Study of Positronium by High Resolution AgeーMomentum Correlation Measurements

Research Project

Project/Area Number 01460031
Research Category

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

Allocation TypeSingle-year Grants
Research Field 固体物性
Research InstitutionThe University of Tokyo

Principal Investigator

HYODO Toshio  The University of Tokyo, The College of Arts and Sciences, Associate Professor, 教養学部, 助教授 (90012484)

Co-Investigator(Kenkyū-buntansha) NAGASHIMA Yasuyuki  The University of Tokyo, The College of Arts and Sciences, Research Associate, 教養学部, 助手 (60198322)
Project Period (FY) 1989 – 1990
Project Status Completed (Fiscal Year 1990)
Budget Amount *help
¥7,400,000 (Direct Cost: ¥7,400,000)
Fiscal Year 1990: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1989: ¥6,500,000 (Direct Cost: ¥6,500,000)
Keywordspositron annihilation / positronium / gamma-ray detector / position sensitive detector
Research Abstract

The positronium is a unique "atom" whose information can be obtained by investigating the angular correlation or the Doppler broadened energy spectrum of its annihilation gamma rays. In this work, we combine the positron lifetime method with the angular-correlation or energy-spectrum method to get more detailed information on positronium. A planer-type high purity Ge detector is used to get high resolution energy spectrum. Position sensitive photomultilipers are used to increase efficiency of the angular correlation system. The following new results are obtained.
(1) The pickoff annihilation cross section of positronium-oxygen collisions has been determined for the first time : Because the ground state of the oxygen molecule is triplet, the ortho-positronium colliding with oxygen is converted into para-positronium at a very high rate. Because of this, it has been believed impossible to measure the ordinary pickoff annihilation cross section. This is made possible in the present work by using the difference between the momentum distributions for the ortho-para conversion and the pickoff annihilation.
(2) Methods to measure the positron spin polarization by the energy spectrum and the angular correlation are established : High precision measurements of positron spin polarization are made by using the asymmetry of the ortho- and para-positronium formation probabilities in a magnetic field.
(3) The momentum transfer crosssection for the positronium-helium collisionin is determined for the first time : This is performed by measuring the time dependence of the momentum distribution of positronium in helium.

Report

(3 results)
  • 1990 Annual Research Report   Final Research Report Summary
  • 1989 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] 長嶋 泰之: "Effect of positron spin Polarization on orthoーpositronium and Para positroniun in a magnetic field" Physical Reuiew. 41. 3937-3942 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] 柿元 満: "Conuersion of orthoーpositronium in low density oxygen gas" Jowrhal of Physics B:Ab、mol.Opt、Phys.23. 589-597 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] 斎藤 晴雄: "A new long lived conpnent in the positron lifetime speetrun im KI at low temyratnes" Journal of Physical Soiety of Japan. 60. 57-60 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] 兵頭 俊夫: "アルカリ・ハライド中のポジトロニウムの自己束縛" 日本物理学会誌. 45. 830-832 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] T.B,Chang: "Pichoff annihilatin rate of arthoーpositronium in oxygen" Physical Reuewに投稿予定.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] Y. Nagashima and T. Hyodo: "Effects of positron spin polarization on orthopositronium and parapositronium formation in a magnetic field" Phys. Rev.B41. 3937-3942 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] M. Kakimoto, T. Hyodo and T. B. Chang: "Conversion of ortho-positronium in low-density oxygen gas" J. Phys. B : At. Mol. Opt. Phys.23. 589-597 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] Haruo Saito and Toshio Hyodo: "A new long-lived component in the positron lifetime spectrum in KI at low temperatures" J. Phys. Soc. Jpn.60. 57-60 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] T. Hyodo: "Self-trapping of positronium in alkali halides" BUTSURI,. 45. 830-832 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] T. B. Chang and T. Hyodo: "Pickoff annihilation rate of ortho-positronium in oxygen" Phys. Rev. A.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] 長嶋 泰之: "Effect of positron spin polarization on orthopositronium and para positronium in a magnetic field" Physical Review. 41. 3937-3942 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] 柿元 満: "Conversion of orthoーpositronium in low density pxygen gas" Journal of Physics B:At.Mol.Opt.Phys.23. 589-597 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] 斎藤 晴雄: "A new long lived component in the positron lifetime spectrum in KI at low terperatines" Journal of Physical Society of Japan. 60. 67-70 (1991)

    • Related Report
      1990 Annual Research Report
  • [Publications] 兵頭 俊夫: "アルカリ・ハライド中のポジトロニウムの自己束縛" 日本物理学会誌. 45. 830-832 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] T.B.Chang: "Pickoff annihilation rate of orthopositronium in oxygen" Physical Review.

    • Related Report
      1990 Annual Research Report
  • [Publications] 柿元満: "Conversion of Orthopsitronium in Low Density Oxygen Gas" J.Physics B:Atomic,Molecular and Optical Physics. (1990)

    • Related Report
      1989 Annual Research Report
  • [Publications] 長嶋康之: "Effects of Positron Spin Polariza tion on Orthopositronium and Parapositronium Formation in a Magnetic Field" Physical Review B. 7. (1990)

    • Related Report
      1989 Annual Research Report

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Published: 1989-04-01   Modified: 2016-04-21  

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