Developments of gamma-ray imagers using CdTe semiconductors based on the analog ASIC technology

Cadmium Telluride (CdTe) is one of the most promising semiconductor materials for hard X-ray and gamma-ray detection because of the high detection efficiency, and of the good energy resolution.Moreover, CdTe detectors with Schottky junction work as diode detectors, and show superior energy resolution. Based on the CdTe diode devices, we have developed CdTe pixel/strip imagers, and also realized a Si/CdTe Compton camera. These devices will be used for the Hard X-ray Imager (HXI) and the Soft Gamma-ray Detector (SGD) onboard ASTRO-H X-ray satellite to be launched in 2015. These developments are briefly reported in this article. We also describe our recent development of low-noise analog readout ASICs to be used for future development of CdTe gamma-ray imagers.