AMORPHOUS-SILICON X-RAY-DETECTORS

Amorphous silicon (a-Si) has proven to be the most suitable semiconduc tor for large-area devices. Our detector prototype with a pixel pitch of 200 mu m and an active area of 20 x 20 cm(2) uses one PIN photodiod e and one PIN switching diode per pixel for readout. Cesium iodide is used as scintillator. Evaluation of the detector was performed in the laboratory as well as in a clinical site where it was integrated in a C-arm for cardiological investigations. In this paper, modulation tran sfer function, dynamic behavior, noise figures, and quantum yield will be discussed. The performance of these detectors represents a first s tep towards the goal of replacing existing fluoroscopic or radiographi c X-ray systems for medical diagnosis. (C) 1998 Elsevier Science B.V. All rights reserved.