| Project/Area Number |
11694104
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | High Energy Accelerator Research Organization (KEK) |
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Principal Investigator |
YOSHIDA Tetsuya High Energy Accelerator Research Organization Institute of Particle and Nuclear Studies, Associate Professor, 素粒子原子核研究所, 助教授 (50222394)
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| Co-Investigator(Kenkyū-buntansha) |
MAKIDA Yasuhiro High Energy Accelerator Research Organization Institute of Particle and Nuclear Studies, Research Associate, 素粒子原子核研究所, 助手 (30199658)
YOSHIMURA Koji High Energy Accelerator Research Organization Institute of Particle and Nuclear Studies, Associate Professor, 素粒子原子核研究所, 助教授 (50272464)
YAMAMOTO Akira High Energy Accelerator Research Organization Cryogenic Science Center, Professor, 低温工学センター, 教授 (30113418)
NOZAKI Mitsuaki Kobe University, School of Sci. & Tech., Professor, 大学院・自然科学研究科, 教授 (10156193)
SANUKI Tomoyuki University of Tokyo, School of Science, Research Associate, 大学院・理学系研究科, 助手 (70323491)
折戸 周治 東京大学, 大学院・理学系研究科, 教授 (10092173)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥13,400,000 (Direct Cost: ¥13,400,000)
Fiscal Year 2000: ¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1999: ¥6,600,000 (Direct Cost: ¥6,600,000)
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| Keywords | BESS Spectrometer / Low Energy Antiproton / Proton / He Spectrum / Cosmic Antimatter / Solar Modulation / Muon Spectrum / Long Duration Flight / 低エネルギー宇宙線反陽子 / 陽子ヘリウムスペクトラム |
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| Research Abstract |
In order to study the origin of the cosmic-ray antiprotons,
1. Two successive balloon-borne experiments with the BESS superconducting spectrometer have been carried out in 1999 and 2000 to measure precise spectrum of the cosmic rays at the solar maximum period. In these flights, more than thousand antiproton events were accumulated.
2. By the data from those flights, charge dependence on the solar modulation was clearly observed, which is inevitable to understand the energy spectrum of secondary antiprotons.
3. A search for antihelium nuclei in the primary cosmic rays has been carried out and an upper limit of the ratio of antiheliums to helium nuclei to be less than 7×10^<-7> was placed, which is most stringent in the world.
4. Precise energy spectrum of primary protons was measured, especially in low energy region below 1 GeV.Using the data during the acsend of the balloon, residual pressure dependence on the proton spectrum was observed in order to check models of the development of cosmic rays in the atmosphere.
5. The 7^<th> BESS workshop was held to evaluate the results from past BESS experiments. For further investigation of the primary origin of the low energy antiprotons, a longer balloon-borne experiment with smaller superconducting spectrometer was discussed and planed by a long duration flight in Antarctica in that workshop.
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