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X-Ray Polarimetry Workshop SLAC, Stanford, California 9-11 February 2004 |
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Octagonal scintillator for hard X-ray polarimetory
Tatehiro
Mihara
RIKEN
mihara@crab.riken.go.jp
Tatehiro Mihara, Hachitaro Miyamoto
Effective method to detect X-ray polarization in 20-100keV is to use non-uniformity of Compton scattering. We made an octagonal scintillator to test the polarization detection. It consists of a scatterer column made of plastic scintillator at the center, and eight surrounding NaI scitillators. There is a BaF2 scintillator at bottom to stop the X-ray beam. All the ten scitillators are read out by a single position-sensitive photo-multiplier. The incident X-ray is scattered by the scatterer and detected by one of the NaIs. The count rate distribution of NaIs gives the polarization direction and degree of polarization. We irradiated synchrotron X-ray (30-80keV) and measured the performance. The M-factor of the octagonal scintillator was 0.41-0.57. Since the photon detection efficiency is designed for very high (~0.4), it gives very high M eta^0.5 value (~0.3), which means very high efficienfy of polarization detection.
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For more information, contact
Jennifer Formichelli |
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