The properties of 32k CdZnTe detectors have been studied in the pre-flight calibration of Burst Alert Telescope (BAT) on-board the Swift Gamma-ray Burst Explorer (scheduled for launch in January 2004). After corrections of the linearity and the gain, the energy resolution of summed spectrum is 7.0 keV (FWHM) at 122 keV. In order to construct response matrices for the BAT instrument, we extracted mobility-lifetime (μτ) products for electrons and holes in the CdZnTe. Based on a new method applied to 57Co spectra taken at different bias voltages, μτ for electrons ranges from 5.0×10-4 to 1.0×10-2cm2V -1, while μτ for holes ranges from 1.0 × 10-5 to 1.7 × 10-4cm2V-1. We show that the distortion of the spectrum and the peak efficiency of the BAT instrument are well reproduced by the μτ database constructed in the calibration.
|出版ステータス||Published - 2004|
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