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Photoconductor‐based (direct) large‐area x‐ray imagers
Author(s) -
Zentai George
Publication year - 2009
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1889/jsid17.6.543
Subject(s) - x ray detector , x ray , photodiode , ghosting , optics , detector , optoelectronics , materials science , active matrix , physics , thin film transistor , nanotechnology , layer (electronics)
Abstract— A brief overview of the present status of active‐matrix flat‐panel direct x‐ray imagers (D‐AMFPI) is given. The spatial resolutions of direct and indirect imagers are compared, and it is pointed out that the lack of light scattering greatly improves resolution. Furthermore, the resolution does not degrade as layers of the x‐ray detector materials become thicker for better x‐ray absorption at higher x‐ray energies, opposite to that of indirect imagers. Different direct x‐ray conversion materials are compared, how the physical properties influence the x‐ray detection efficiency, and imager stability are discussed. Ghosting and image‐lag properties are also weighted. A few x‐ray‐sensitive photoconductor materials produce very‐high x‐ray conversion efficiency, which could be advantageous for low‐dose fluoroscopy to overcome the noise of the readout electronics. Last, but not least, the manufacturing advantage of the direct imagers is emphasized. The direct imagers do not need p‐i‐n photodiodes, so the a‐Si TFT matrices for these arrays can be manufactured at any LCD manufacturing sites and not only at a few, very specialized companies where the p ‐layers for the photodiodes can be deposited.