Evaluation of a Large Area, 83 μm Pixel Pitch Amorphous Selenium Indirect Flat Panel Detector

• Published in: IEEE transactions on electron devices Vol. 71; no. 1; pp. 676 - 680
• Main Authors: Hellier, Kaitlin, Mollov, Ivan, Swaby, Akyl, Pryor, Paul, Abbaszadeh, Shiva
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.01.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Amorphous selenium; Design; Detectors; flat panel detector (FPD); Flat panels; Image resolution; indirect detector; large area detector; Performance enhancement; Performance evaluation; Photometers; Photonics; Pixels; Quantum efficiency; Scintillation counters; Scintillators; Selenium; Sensors; Thin film transistors; Transfer functions; X ray imagery; X-ray detector; X-ray imaging; Amorphous selenium; flat panel detector (FPD); X-ray detector; large area detector; indirect detector
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2023.3338131

Dual-layer detectors provide a low-cost solution to improved material decomposition and lesion differentiation in X-ray imaging, while eliminating motion artifacts from multiple exposures. Most designs utilize two indirect detectors with scintillators designed for low-energy and higher-energy detection and separated by a copper filter to harden the beam for high energy detection. To improve the performance of the bottom detector and lower dose requirements, we have previously proposed an alloyed amorphous selenium photodetector to achieve improved resolution and absorption at green wavelengths, better suited to high-performance scintillators such as CsI:Tl. In this work, we demonstrate a baseline prototype for the bottom layer-a continuous, large area <inline-formula> <tex-math notation="LaTeX">83~\mu \text{m} </tex-math></inline-formula> pixel pitch flat panel indirect detector with well-established amorphous selenium as the photodetector-and verify the architecture's performance and detector design. We characterize lag, noise-power spectrum, detective quantum efficiency, and modular transfer function of the detector, and show resolution up to 6 lp/mm when operated at an applied bias of 150 V. This provides a starting point for evaluating the alloyed selenium materials, and shows promise for this detector in the future dual-layer design.