PD-HEXID1: A Low-Power, Low-Noise Pixel Readout ASIC for Pixelated-Scintillator-Based X-Ray Detectors

A low-power, low-noise pixel readout application-specific-integrated-circuit (ASIC) prototype with embedded in-pixel photo-diode was developed for a novel pixelated-scintillator-based X-ray detector, capable of spectral energy discrimination and suitable for low dose whole body CT imaging. The ASIC includes 8-by-16 channels to read out negative charges detected by the built-in photodiodes, at a pitch size of 250 µm to achieve good spatial and energy resolution energy of detected photons. Each channel of the ASIC provides low-noise charge amplification, high-order shaping with baseline stabilization, discrimination, extraction of amplitude including neighbor channels, multiplexing, and dissipates ~0.6 mW. The measured equivalent noise charge (ENC) is about 20 rms electrons at 500 ns peaking time. The ASIC with built-in photodiodes has demonstrated high sensitivity to light.