| Project/Area Number |
12304032
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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 |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | University of Tsukuba |
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Principal Investigator |
FURUNO Kohei University of Tsukuba, Institute of Physics, Professor, 物理学系, 教授 (40015772)
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| Co-Investigator(Kenkyū-buntansha) |
KUROSAWA Masaki University of Teukuba, Institute of Geoscience, Assistant Professor, 地球科学系, 講師 (50272141)
KATOH Takumi University of Teukuba, Institute of Geoscience, Associate Professor, 地球科学系, 助教授 (90214379)
MIYANO Takashi University of Tsukuba, Institute of Geoscience, Professor, 地球科学系, 教授 (60133039)
SASA Kimikazu University of Tsukuba, Institute of Physics, Assistant Professor, 物理学系, 講師 (20312796)
KOMATSUBARA Tetsuro University of Tsukuba, Institute of Physics, Assistant Professor, 物理学系, 講師 (10195852)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥21,190,000 (Direct Cost: ¥16,300,000、Indirect Cost: ¥4,890,000)
Fiscal Year 2002: ¥8,320,000 (Direct Cost: ¥6,400,000、Indirect Cost: ¥1,920,000)
Fiscal Year 2001: ¥12,870,000 (Direct Cost: ¥9,900,000、Indirect Cost: ¥2,970,000)
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| Keywords | NRA / Microbeam / Hydrogen analysis / ERDA / Hydrogen in rocks and Minerals / 岩石・鉱物水濃度 |
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| Research Abstract |
The development of a new high-energy ion microprobe and improvements of experimental methods were carried out using the beams of 16〜25 MeV ^<19>F ions and 20 MeV protons obtained from the tandem accelerator in the University of Tsukuba. It is aimed at the measurement of hydrogen concentration in melt inclusions, which was rather difficult with such a conventional method as SIMS. The results are as follows.
1. A high-energy ion microprobe dedicated to the investigation of earth science was successfully constructed.
2. The lateral size of beam spot is 30μm, which is sufficiently small since the majority of melt inclusions are larger than 30μm. In NRA the deepest depth is 4μm from the sample surface ; the depth resolution of hydrogen distribution is 0.1μm ; the sensitivity is as low as 50 wt. ppm H_20 by ^1H(^<19>F, α γ)^<16>O reaction ; and the relative overall uncertainty is 15%. In ERDA, the thickness of samples is 0.2 mm ; the depth resolution is 5μm ; the sensitivity is as low as 10 wt. ppm H_2O by employing proton-proton coincidence method ; and the relative overall uncertainty is 15%.
3. A hydrogen bearing standard sample was prepared by ion implantation, and its hydrogen concentration was calibrated by α-γ angular correlation in the ^1H(^<19>F, α γ)^<16>O reaction with a relative overall uncertainty of 9.7%.
4. Computer programs were developed to extract most likely hydrogen distributions by unfolding from excitation functions obtained in NRA or sum-energy spectra in proton-proton coincidence ERDA.
5. The hydrogen concentration in the granite of a bridge in Hiroshima city was measured for the reevaluation of neutron flux emitted from the atomic bomb. Hydrogen in melt inclusions confined in some volcanic ashes was also measured.
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