Readout QDC for CdTe x-ray imager using direct charge treatment

X-ray imaging is popular in medical imaging, non-destructive testing and security. Main techniques of X-ray imaging with semiconductor detectors are charge accumulation and photon counting, and the photon counting is expected to identify materials at the same time with taking X-ray photograph by using energy information of X-ray photons. We proposed a direct charge handling method to build a photon counting system with energy information for X-ray imaging. This method operates the charge from the X-ray detector and converts it to encoded digital bit pattern directly without dead time of the front-end circuit. We simulated and built a proposed system to prove operating principals.