| Project/Area Number |
13354007
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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 | 展開研究 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Okayama University of Science |
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Principal Investigator |
ITAYA Tetsumaru Okayama University of Science, Research Institute of Natural Sciences, Professor, 自然科学研究所, 教授 (60148682)
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| Co-Investigator(Kenkyū-buntansha) |
HYODO Hironobu Okayama University of Science, Research Institute of Natural Sciences, Associate Professor, 自然科学研究所, 助教授 (50218749)
YAMAMOTO Isao Okayama University of Science, Faculty of Science, Professor, 工学部, 教授 (50090220)
岡田 利典 海洋科学技術センター, IFREE, 技術研究員
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥27,690,000 (Direct Cost: ¥21,300,000、Indirect Cost: ¥6,390,000)
Fiscal Year 2003: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2002: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2001: ¥20,930,000 (Direct Cost: ¥16,100,000、Indirect Cost: ¥4,830,000)
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| Keywords | Ar-Ar dating method / multi-detector / microchannel plates / position sensitive detector / Backgammon method / ion counting method / neutron irradiation / single mineral age / 単結晶鉱物年代 |
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| Research Abstract |
In 40Ar/39Ar stepwise heating experiments, the fast measurements need to be carried out to obtain time-independent data sets, in particular for small samples. In this study, microchannel plates are used for ion detection, and simultaneous measurement of five argon isotopes from 36Ar to 40Ar was attempted.
Simple combination of microchannel plates and a position sensitive detector is not suitable in an ultrahigh vacuum system because it needs baking at temperature over 100℃. Thus, we adopted the two dimensional Modified Backgammon method with Weighted coupling Capacitors(MBWC) designed by Drs Mizokawa at Wakayama College of Technology and Shiromaru at Tokyo Metropolitan University.
36Ar,38Ar and 40Ar from atmosphere were detected simultaneously, but the system was not enough for quantitative measurements. The large volume of 40Ar disturbs the simultaneous measurement of 36Ar and 38AT signals which is approximately one three hundredth and one sixteen hundredth, respectively. The system allows two dimensional ion detection, and it is effective to adjust ion optics of each isotope in a mass spectrometer.
Designing an one-dimensional chain of linear channeltron was considered to make quantitative measurements, and it became possible with coorperation with Dune Inc. Combining the two dimensional system and a small mass spectrometer with one dimensional system allow easy tuning of ion optics and highly sensitive quantitative argon mass spectrometry. Independent developments of two different types of mass spectromenters is now resulting in a new ultra small highly sensitive mass spectrometer.
Signals from the position sensitive detector is measured by the ion counting method. The interface and program were developed as well as the automatic control for the measurement. The control and measurement units are connected via LAN cable. The extraction and purification system to separate ultra low volumes of the standard air and high purity gases were completed.
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