  We developed CdTe double-sided strip detectors (DSDs or cross strip
detectors) and evaluated their spectral and imaging performance for hard X-rays
and gamma-rays. Though the double-sided strip configuration is suitable for
imagers with a fine position resolution and a large detection area, CdTe diode
DSDs with indium (In) anodes have yet to be realized due to the difficulty
posed by the segmented In anodes. CdTe diode devices with aluminum (Al) anodes
were recently established, followed by a CdTe device in which the Al anodes
could be segmented into strips. We developed CdTe double-sided strip devices
having Pt cathode strips and Al anode strips, and assembled prototype CdTe
DSDs. These prototypes have a strip pitch of 400 micrometer. Signals from the
strips are processed with analog ASICs (application specific integrated
circuits). We have successfully performed gamma-ray imaging spectroscopy with a
position resolution of 400 micrometer. Energy resolution of 1.8 keV (FWHM: full
width at half maximum) was obtained at 59.54 keV. Moreover, the possibility of
improved spectral performance by utilizing the energy information of both side
strips was demonstrated. We designed and fabricated a new analog ASIC, VA32TA6,
for the readout of semiconductor detectors, which is also suitable for DSDs. A
new feature of the ASIC is its internal ADC function. We confirmed this
function and good noise performance that reaches an equivalent noise charge of
110 e- under the condition of 3-4 pF input capacitance.
