Which photo conductor is commonly used with a TFT array in direct digital imaging?

Which photo conductor is commonly used with a TFT array in direct digital imaging?

• A. Amorphous silicon (a-Si)
• B. Amorphous selenium (a-Se)
• C. Cadmium zinc telluride (CZT)
• D. Silicon carbide (SiC)

Answer: (B)

In direct digital imaging, the photoconductor that is most commonly used with a thin-film transistor (TFT) array is amorphous selenium (a-Se). This material is crucial because it has excellent properties for converting incoming X-ray photons into electrical signals, which are then read by the TFTs to produce high-quality digital images.

Amorphous selenium provides a high atomic number, which enhances its efficiency in interacting with X-rays, resulting in better image contrast and resolution. Its direct conversion ability means it can efficiently convert X-ray energy into electric charges without the need for intermediate steps, which helps to improve overall image quality and speed. These attributes make a-Se a popular choice in direct radiography technologies employed in modern imaging equipment.

While other materials listed have their applications in different types of imaging systems or in specific contexts, they do not serve the same role in conjunction with TFT arrays in direct digital imaging as effectively as amorphous selenium.