| Project/Area Number |
11559019
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
広領域
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| Research Institution | High Energy Accelerator research Organization (KEK) |
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Principal Investigator |
MIYAKE Yasuhiro KEK, Associate Professor, 物質構造科学研究所, 助教授 (80209882)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIYAMA Kusuo KEK, Professor, 物質構造科学研究所, 教授 (50164611)
SHIMOMURA Koichiro KEK, Research Associate, 物質構造科学研究所, 助手 (60242103)
NAGAMINE Kanetada KEK, Professor, 物質構造科学研究所, 教授 (50010947)
MATSUDA Yasuyuki RIKEN, Researcher, ミュオン科学, 研究員
STRASSER Patrich RIKEN, Research Fellow
西山 樟生 高エネルギー加速器研究機構, 物質構造科学研究所, 教授 (04044038)
ストラッサー パトリック 理化学研究所, ミュオン科学, 契約研究員
パトリックス ストラッサー 理化学研究所, ミュオン科学, 契約研究員
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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 |
¥13,200,000 (Direct Cost: ¥13,200,000)
Fiscal Year 2001: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥5,100,000 (Direct Cost: ¥5,100,000)
Fiscal Year 1999: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Keywords | muon / polarization / spin / ultra slow / solid state physics / Hydrogen / surface / Laser / VUV |
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| Research Abstract |
We have been collaborating with the RIKEN-RAL muon science group on the ultra slow muon generation by the laser resonant ionization method. Construction of the slow ion optics at Port 3 at RIKEN-RAL muon facility was completed on the summer of 2001. Then we had a chance of muon beam time for 5 days at Port3 where about 5 x 105 surface muons/s beam with a momentum of 27 MeV/c is available. The proton accelerator operates at 50Hz repetition rate, therefore the laser system was operated synchronized with the every second muon pulse(25Hz).
We could observe a clear peak only when laser lights were introduced, but not when laser lights were not introduced. Also this peak was observed in the expected TOF and in the expected MASS/Q corresponding to the slow muon.
We also measured dependence of the slow muon yield as a function of the difference wavelength. It peaked at 820.4 nm. This evidence is showing that Mu is ionized through the 1s-2p transition. On the other hand, the Lyman-α light for Mu
… More
was experimentally calibrated by this measurement. This is why we claimed we succeeded in the slow muon generation by the laser resonant ionization method originated from the surface muon beam. During this measurement, the rate of the slow muon was 0.03μ+/s. There are considered several reasons why the rate was so small. The first reason is that a lot of fraction of the surface muon beam is blocked by a collimator with a small aperture. We have to redesign the beam duct without the collimator on the way to the slow ion optics. The second is that we had no time to adjust the momentum of the surface muon so that surface muon stops on the rear surface of the tungsten target.
We may have to exchange tangsten foils of 50 and 25μm, since momentum of the surface muon can be reduced by the several beam windows. The third is that we need to improve the VUV (Vacuum Ultra Violet) generation which is lower than one or two order of magnitude compared with the KEK laser system.
By improving those experimental conditions, we expect at least 100 to 1000 times larger yield of the slow muons which will be suitable for the μ+SR studies. Less
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