| Project/Area Number |
06808046
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
プラズマ理工学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MICHISHITA Toshinori Kyoto University, Human Integrated Studies, Instructor, 総合人間学部, 助手 (00166050)
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| Co-Investigator(Kenkyū-buntansha) |
MAEKAWA Satoru Kyoto University, Huma and Envionmental Studies, Associate Professor, 人間環境学研究科, 助教授 (40135489)
KAWASE Youichi Kyoto University, Reactor Research Institute, Professor, 原子炉実験所, 教授 (60027448)
TANAKA Hitoshi Kyoto University, Energy Science, associate Professor, エネルギー科学研究科, 助教授 (90183863)
YUYAMA Tetsumori Kyoto University, Human Integrated Studies, Instructor, 総合人間学部, 助手 (90026815)
MOHRI Akihiro Kyoto University, Human Integrated Studies, Professor, 総合人間学部, 教授 (10025926)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Positron / condensed phase / Plasma / Monte-Carlo Simulation / molecular dynamics / 陽電子凝縮系 / 超高磁場 / 長時間閉じ込め / 相関パラメータ / サイクロトロン放射減衰 / ペニング型閉じ込め / ライナック / モンテカルロ法 |
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| Research Abstract |
Our research on condensed phase of positrons leads the following results ;
1) Positrons are produced via pair-creation mechanism with an electron beam linac and are transported to the confinement region with a relatively low magnetic field (*0.03T) and a multi-ring electrode system. Then they are slowed down by using a rare-gas solid coolant. The number of thermal and epithermal positrons confined are of order of 10^6.
2) A Monte-Carlo simulation makes it clear that exiciton excitation plays a predominant role of energy relaxation of positrons in rare-gas solids.
3) Positrons emitted from ^<22>Na with 3.7 MBq are injected into a vacuum system with a high magnetic field (8T) and multi-ring electrodes. Positrons with number of 2.7*10^5 are confined. Only a classical plasma is observed due to fluctuations originated from the irregularity of the magnetic and electric fields as well as due to high temperature as large as the room one.
4) A molecular dynamics simulation is performed to make it clear parameter dependences of condensed phase of positrons. a) In a modified Penning trap positrons exhibit liquid like in the direction of the magnetic field and solid like in the radial direction in a condition of low temperature *1K.b) The correlation function GAMMA becomes of order of 10^2 for positrons with temperature *1K and the density corresponding to the Wigner-Seitz radius of gamma_s >>1.
Theses indicate that positrons should be surrounded by matter with extremely low temperature, for an example, He-II.
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