ASIC With Multiple Energy Discrimination for High-Rate Photon Counting Applications

An ASIC for high rate photon counting measurements with multiple energy discrimination is presented. Optimized for pixelated CdZnTe sensors, the ASIC is composed of 64 channels with low-noise charge preamplification, high-order shaping (40 ns minimum peaking time), and five window-discriminators with associated 16-bit counters. An efficient readout scheme allows simultaneous measurement and readout through a 60 MHz 16-bit output bus. The ASIC architecture and experimental results are reported, and the impact of the shaper order on the resolution, ballistic deficit, and pile-up is discussed