| Project/Area Number |
11680516
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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 |
Nuclear engineering
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| Research Institution | Osaka University |
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Principal Investigator |
HONDA Yoshihide Osaka University, ISIR, Research Associate, 産業科学研究所, 助手 (40209333)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Yoichi Osaka University, ISIR, Associate Professor, 産業科学研究所, 助教授 (50210729)
NISHIJIMA Shigehiro Osaka University, Graduate school of engineering, Professor, 大学院・工学研究所, 教授 (00156069)
TAGAWA Seiichi Osaka University, ISIR, Professor, 産業科学研究所, 教授 (80011203)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2001: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Positron / Positronium / Synchronization / Multiple irradiation / Pulsed positron beam / Electron linear accelerator |
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| Research Abstract |
To investigate the interactions between positronium and the materials using laser-synchronized system, we have developed two kinds of short pulsed positron beams based on L-band and S-band electron linear accelerators (linacs) which are characterized by high density and high count rate.
A new facility based on L-band linac (maximum energy: 38 MeV, pulse width: 20 ps) was designed and constructed for the purpose of the investigation of the status of positronium in the materials by exciting positronium with ultra short pulsed laser. In the experiments, the number of positrons coming from the target with the energy corresponding to the applied voltage was about 2500 per pulse and the pulse width was about 20 ns (FWHM) by measuring annihilation gamma rays. These values were rather low compared with the computational estimation. This results could be mainly ascribed to improper positioning of the positron beam because of bright electron image.
The several phenomena such as excitation of the specialized molecules and vibration, can be introduced by laser irradiation and the lifetime of the positronium is influenced through the interactions. We also developed another new short pulsed positron beam facility based on S-band linac for the use of this kind of experiment. The pulse width of this positron beam could be attained about 370 ps. Using this positron beam, we started the measurement of positron lifetime in several materials with regular structure such as LB films and several derivatives, to investigate the interactions mentioned above. The experiments with laser excitation will be started soon.
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