2004 Fiscal Year Final Research Report Summary
Development of Gamma-ray burst Polarization Monitor(GAPOM)
| Project/Area Number |
14340065
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | The Institute of Physical and Chemical Research |
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Principal Investigator |
MIHARA Tatehiro RIKEN, Cosmic radiation laboratory, senior researcher, 牧島宇宙放射線研究室, 先任研究員 (20260200)
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| Co-Investigator(Kenkyū-buntansha) |
KUBO Hidetoshi Kyoto university, graduate school of science, assistant, 大学院・理学研究科, 助手 (40300868)
TAMAGAWA Toru RIKEN, Cosmic radiation laboratory, researcher, 牧島宇宙放射線研究室, 研究員 (20333312)
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| Project Period (FY) |
2002 – 2004
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| Keywords | X-ray polarization / scattering polarimeter / GAPOM / gamma-ray burst / octagonal scintillator / imagine polarimeter |
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| Research Abstract |
In 2002,we build one-cell model which is a basic model of GAPOM(Gamma-ray burst polarization monitor), and octagonal scintillator which is an evaluative model of GAPOM. We irradiate X-ray to both models with X-ray generator in the laboratory and synchrotron X-ray in KEK Photon factory. Obtained results are compared to the simulation. The measured values such as photon detection efficiency, event ratios, polarization detectability are confirmed to be as expected.
In 2003,we employed segmented plastic scintillator as the scatterer to have a position detectability. It consists of 52 long bars of plastic scintillators. The Compton loss in them gives position information. On the other hand we used Geant4 montecarlo scimulation and compared the calculated results with obtained data. They agree well.
In 2004,we build CdTe head unit. It uses 16 pieces of CdTe semiconductor detectors as absorbers, which leads to a better energy resolution than NaI or CsI scintillators. We irradiated 80 keV polarized X-ray in KEK PF. The spectra showed single peak in the most-X-ray direction, and two peaks in the least-X-ray direction. It represents the angular dependence of the Compton scattering, and the results are as expected by Geant4 simulation. The obtained polarization detection efficiency was M=0.67, which is a high value and confirmed good efficiency.
Also, we built 8x8 segmented plastic scintillators with H8500 photomultiplier. With 10 detectors of this type we can observe the Crab nebula with balloon experiment.
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