A single detector element (DEL) comprises which set of components?

• A. Top electrode, a detection layer, and bottom electrode
• B. Capture area, storage capacitor, and thin film transistor (TFT) gate
• C. Thin film transistor (TFT) gate, detection layer, and storage capacitor
• D. Top electrode, capture area, and bottom electrode

Answer: (B)

The detector element is the addressable unit that converts X-ray energy into charge, stores that charge, and then releases it for readout. The essential set includes the capture area where the X-ray–to–charge conversion happens, the storage capacitor that holds that charge until the pixel is read, and the thin-film transistor gate that acts as the switch to connect the stored charge to the readout line. Top/bottom electrodes or a separate detection layer are part of the detector’s construction, but the defining functional trio for a single DEL is capture area, storage capacitor, and TFT gate.