Imaging principle of amorphous selenium flat panel detector

When X-rays irradiate the amorphous selenium layer in a preset initial state and excite electron-hole pairs, the electron and hole pairs move in the opposite direction under the action of an external electric field to generate a current. The current size is proportional to the incident ray photon In direct proportion to the number, these current signals are stored in the inter-electrode capacitance of the TFT, and each TFT and the capacitor form a pixel unit. Finally, the stored charge of the TFT layer is read out, amplified and converted by A-D, and then output to the computer to restore the image. After all the charge signals are read out, the residual charge will be eliminated to return to the initial state.

Author：Lillian