1995 Fiscal Year Final Research Report Summary
Imaging Gas Scintillation Proportioanl Counters with Very Low Background
| Project/Area Number |
05452031
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
OHASHI Ekaya Tokyo Metropolitan University, Physics, Associate Professor, 理学部, 助教授 (70183027)
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| Co-Investigator(Kenkyū-buntansha) |
MAKISHIMA Kazuo Tokyo Metropolitan University, Physics, Professor, 大学院・理学系研究科, 教授 (20126163)
YAMASAKI Noriko University of Tokyo , Physics, Res.Associate, 理学部, 助手 (20254146)
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| Project Period (FY) |
1993 – 1995
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| Keywords | X-ray astronomy / X-ray detectors / Energy resolution / Scientific satellites |
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| Research Abstract |
Imaging gas scintillation proportional counters (GSPC) have been successfully used in the X-ray astronomy satellite ASCA with good energy resolution, wide effective area, and high sensitivity to high-energy X-rays. The aim of this research is to improve the performance of these counters in the efficiency of background rejection and in the position resolution by introducing a driftless type of gas-cell. Gas cells of driftless design with an inner diameter of 93mm and a height of 20-25mm have been produced. This is first tested with an ordinary (not position sensitive) phototube to study the background performance. The output signals of GSPC are processed with an wave-form digitizer which gives detaled information about the time variation of the light emission due to gas scintillation in the gas cell as well as the depth of the X-ray absorption. By comparing the time of light emission between the first and the second halves of the total light, we can suppress the background in the high energy range. In the low energy range below 3 keV where X-rays are always absorbed in the very close region from the entrance window, the information of the depth of the X-ray absorption is used to eliminate the background. We have reduced the background rate down to less than 10% of the ASCA level. The position resolution of the driftless GSPC is studied by combining the gas cell with an imaging phototube. The X-rays from an X-ray generator are collimated to 0.1mm diameter, and a position resolution of 0.3mm (FWHM) at 6 keV has been obtained. This is nearly twice as good as that ot the ASCA GSPC.Therefore, a significant improvement in the performance of imaging GSPC has been resulted from the present study. We hope that this instrument will be widely used in various research areas.
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