The Si/CdTe semiconductor detector for hard X-ray imager (HXI) onboard ASTRO-H

The hard X-ray imager (HXI) is the focal plane detector onboard ASTRO-H to be launched in 2014. By combining with the hard X-ray telescope, the HXI will realize the focusing imaging in the energy range from 5 up to 80 keV. The sensitivity of the HXI for an isolated point source will be two orders of magnitude better compared with previous missions. The hybrid structure composed of four layers of double-sided silicon strip detectors (DSSD) and one layer of cadmium telluride double-sided strip detector (CdTe-DSD) enables high detection efficiency in the hard X-ray band. The DSSD and CdTe-DSD for ASTRO-H have been developed, and their spectral and imaging performances were evaluated. By using two-strip events for the reconstructions of spectra and images, energy resolution of 1.0 keV at 13.9 keV and 2.0 keV at 59.5 keV, and sub-strip spatial resolution were achieved.