A study of increase in maximum count rates and energy bins of photon counting pixel detectors

The photon counting pixel detectors have several advantages over charge integrating pixel detectors such as signal-to-noise ratio, contrast, dark current, dynamic range, and spectral information. Nevertheless, the charge integrating pixel detectors have been broadly used as a radiation imager for last two decades. The reason why the photon counting detectors have not been widely used is that the photon counting pixel detectors are more complex and expensive than charge integrating pixel detectors. Furthermore, photon counting pixel detectors have a count-rate limitation and limited number of energy channels. The recent development of the room-temperature semiconductor detectors, the fast readout ASICs, and the flip-chip bonding have made possible for the hybrid type pixel detectors to be considered as a next generation imaging device in various radiation imaging fields. In this research, we proposed new schemes, a dual-path readout circuit and a patterned pixel array, to increase the maximum count rates and to obtain more energy bins than the given number of thresholds in a single pixel, respectively. Monte Carlo simulations and experiments with the fabricated ASIC were perfromed to verify proposed ideas