X-ray Imaging using Room Temperature Semiconductor Detector by Charge-Counting Method

Abstract

  It is expected that image quality will be improved by using energy information for X-ray imaging because X-ray spectrum contains more information than dose measurement. However, it is necessary to implement a spectrum measurement circuit on all pixels of the two-dimensional detector, which hinders the realization. Therefore, we propose the method of the readout circuit, regarded the direct conversion method by the semiconductor detector as a quantizer that quantizes the energy of X-ray photon with electric charge, and sampled each photon while counting the amount of the charge. The proposed circuit has been realized as ROIC by CMOS technology, and it operates as an X-ray imager by stacking semiconductor detectors. The imaging operation has been confirmed by taking images with X-ray. In addition, it has been confirmed by fabricating imagers using CdTe and TlBr respectively that the ROIC supports semiconductor detectors with different physical characteristics.