This description from the astro-H webpage (http://astro-h.isas.jaxa.jp/si/01_e.html) pretty much says it all:
“ The HXI consists of four-layers of 0.5 mm thick Double-sided Silicon Strip Detectors (DSSD) and one layer of 0.5—1 mm thick CdTe imaging detector. In this configuration, soft X-ray photons will be absorbed in the Si part (DSSD), while hard X-ray photons go through the Si part and are detected by the newly developed CdTe double strip detector. Fast timing response of silicon strip detector and CdTe strip detector allows us to place the whole detector inside very deep well of the active shield made of BGO (Bi4G3O12). Signal from the BGO shield is used to reject background events. The total thickness of the four DSSDs is 2 mm, the same as that of the PIN detector of the HXD onboard Suzaku. The DSSDs cover the energy below 30 keV while the CdTe strip detector covers the 20-80 keV band.”
We need to add (http://astro-h.isas.jaxa.jp/references/pdf/ASTRO-H-HXI-SGD-TIPP2009.pdf) that
* the pitch of the DSSSDs is 250 micron (128 channels),
* The pitch of the DS-CdTe is 400 um.
* Note that these DS-CdTe are CdTe STRIP detectors, not actual pixels.
-BG
