The types of flat panel detectors can be roughly divided into amorphous silicon type and amorphous selenium type.
1. Amorphous silicon type flat panel detector, which is mainly composed of scintillation layer or selenium layer, matrix board and glass substrate, readout circuit, etc. Its good density and spatial resolution represent the main direction of current development. High-quality images can be obtained under low-dose exposure. Because of the fast imaging, it can be used in fields such as fluoroscopy and time subtraction, greatly increasing the scope of X-ray inspection.
2. Amorphous selenium type flat-panel detectors, using selenium as a photoconductor can directly convert optical signals into electrical signals to avoid scattering. However, the X-ray absorption rate is low, and the image quality cannot be guaranteed under low-dose conditions. Moreover, the selenium layer is more sensitive to temperature, and its use conditions are limited.
Amorphous silicon is the most ideal material for X-ray receivers, because amorphous silicon is immune to radiation damage.
The above is the main structure of the flat panel detector. The flat panel detector and the X-ray tube constitute the main part of the direct digital imaging.
Flat-panel detectors can be converted in the above two ways, and their main difference lies in the difference in their manufacturing structure. Therefore, the above two types of detectors have their own advantages and disadvantages.