| Project/Area Number |
08554015
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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 |
Space and upper atmospheric physics
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| Research Institution | The Institute of Space and Astronautical Science |
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Principal Investigator |
TSURUDA Koichiro The Institute of Space and Astronautical Science Planetary Atmosphere Sounding Instrumentation Professor, 惑星大気計測学, 教授 (10013682)
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| Co-Investigator(Kenkyū-buntansha) |
HAYAKAWA Hajime The Institute of Space and Astronautical Science Magnetospheric Plasma Physics A, 磁気圏物理学, 助教授 (90167594)
MUKAI Toshifumi The Institute of Space and Astronautical Science Magnetospheric Plasma Physics P, 磁気圏物理学, 教授 (60013695)
山本 達人 宇宙科学研究所, 磁気圏物理学, 教授 (90182633)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥7,100,000 (Direct Cost: ¥7,100,000)
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| Keywords | mass spectrometer / TOF / neutral gas / velocity distribution function / upper atmosphere / CCD / MCP / 中性ガス質量分析 / 飛翔体搭載 / 質量分析 / 酸素原子 |
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| Research Abstract |
A new type of neutral gas mass spectrometer has been developed aiming at application for the upper atmosphere of the earth, Mars and Venus. The mass spectrometers so far used in the upper atmosphere studies only measure the mass distribution of the neutral gas and no measurement of velocity distribution function has been attempted. The velocity distribution function gives the velocity and temperature of each component of the neutral gas to be measured, but it also carries information of non-thermal component and its history, especially in the upper atmosphere where the collisions among atoms and molecules are negligible.
We have combined the time of flight (TOF) technology and the position detection technology to realize an instrument to measure the mass distribution of neutral gas and the velocity distribution. The measurement principle is as follows : The incident neutral gas is ionized by a short (100 nsec) pulse of electron beam located at the center of the instrument. After a few micro second, an electric field is applied to accelerate the newly born ions perpendicular roughly to the incident gas direction toward the MOP (micro channel plate). The MOP is operated in the pulse mode and activated at a time corresponding to the travel time of ions of specific mass. Thus the MOP acts as a mass filter. The output electrons from the MOP illuminates the phosphor plate placed behind the MOP and its luminosity is detected by the GOD (charge coupled device) which gives the velocity distribution.
By the development under this research fund we reached the following conclusions ;
1. The measurement of the mass distribution and velocity distribution function is possible by the above mentioned principle, however,
2. further improvement in the shaping of the ionizing electron beam is necessary to suppress the spurious peaks in the mass distribution.
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