A CdTe-CMOS hybrid for energy, position and time identification

A 2-D pixel CMOS ASIC has been developed for the needs of a Compton imaging instrument. The ASIC consists of a 50×25 pixels array with 400um pitch and an embedded controller. The pixel includes charge amplifier and shaper, peak detector, hit flag comparator, time to voltage converter, configuration registers, in-pixel A/D conversion and DRAM for digital data storage. For the in-pixel A/D conversion a Wilkinson scheme is used. Data are readout only from the pixels which have received hit. The circuit works in snapshot mode with adjustable frame time. The ASIC has been bump bonded to CdTe pixel detectors and the hybrid has been irradiated with radioactive sources and characterized.