X-ray photon counting by perovskite CsPbBr3 detectors with resolved k-edge and improved count rate

Traditional X-ray detectors work at energy integrating mode that does not resolve the energy of individual X-ray photons. X-ray photon counting is an emerging technique that aims at resolving single photon energy, which enables higher X-ray image quality with more information about scanned object at a lower X-ray dose. Recently, perovskite materials have demonstrated promising performance for hard X-ray and gamma-ray detection. In our previous work, we reported the performance of our perovskite CsPbBr3photon counting detectors that can count an incident X-ray photon rate of $0.099 \mathrm{Mcps} /$ pixel at 10% deadtime loss under reasonable pulse processing conditions. Here, we report further development of perovskite CsPbBr3photon counting detectors. When indium, barium, or lead was used separately as the scanned object, the transmitted X-ray energy spectrum acquired by the CsPbBr3detector clearly resolved the feature due to the k-edge discontinuity of their X-ray attenuation coefficient. Besides, with improvement on the crystal quality and device fabrication, we were able to operate the CsPbBr3detector at a higher voltage, e.g., 1200 V reverse bias for a 1 mm thick detector vs 350 V for 1 mm detector in our previous work. The higher bias voltage leads to reduced charge drifting time, and consequently, the count rate performance was improved compared to previous results.