IDeF-X V1.1: Performances of a New CMOS 16 Channels Analogue Readout ASIC for Cd(Zn)Te Detectors

A new full custom readout ASIC is presented. Its name is IDeF-X V1.1 for Imaging Detector Front-end. The actual version of the IDeF-X ASIC is a complete 16 channels analogue front-end with self triggering capability. The chip has been optimized for high resolution, X ray or gamma ray spectroscopy (4 to 300 keV). Each channel includes a charge sensitive preamplifier with a continuous reset system, a pole zero cancellation system, a fourth order Sallen & Key type shaper with variable peaking time, a stretcher (peak detector plus storage capacitor) and a discriminator with a low level threshold common to all channels. An analogue multiplexer followed by an output buffer is used to read each stretcher output. All the discriminators feed a trigger output to the external data acquisition system. The electronic chain is optimized for detector capacitance from 2 to 5 pF.