Exploration of maximum count rate capabilities for large-area photon counting arrays based on polycrystalline silicon thin-film transistors
| Autor: | Qihua Zhao, Youcef El-Mohri, Larry E. Antonuk, Albert K. Liang, Martin Koniczek |
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| Rok vydání: | 2016 |
| Předmět: |
Amorphous silicon
Materials science Physics::Instrumentation and Detectors ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION 02 engineering and technology engineering.material 030218 nuclear medicine & medical imaging law.invention 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Optics law Clock generator Crystalline silicon Electronic circuit business.industry Amplifier Transistor 021001 nanoscience & nanotechnology Photon counting Polycrystalline silicon chemistry engineering Optoelectronics 0210 nano-technology business |
| Zdroj: | SPIE Proceedings. |
| ISSN: | 0277-786X |
| DOI: | 10.1117/12.2216944 |
| Popis: | Pixelated photon counting detectors with energy discrimination capabilities are of increasing clinical interest for x-ray imaging. Such detectors, presently in clinical use for mammography and under development for breast tomosynthesis and spectral CT, usually employ in-pixel circuits based on crystalline silicon – a semiconductor material that is generally not well-suited for economic manufacture of large-area devices. One interesting alternative semiconductor is polycrystalline silicon (poly-Si), a thin-film technology capable of creating very large-area, monolithic devices. Similar to crystalline silicon, poly-Si allows implementation of the type of fast, complex, in-pixel circuitry required for photon counting – operating at processing speeds that are not possible with amorphous silicon (the material currently used for large-area, active matrix, flat-panel imagers). The pixel circuits of two-dimensional photon counting arrays are generally comprised of four stages: amplifier, comparator, clock generator and counter. The analog front-end (in particular, the amplifier) strongly influences performance and is therefore of interest to study. In this paper, the relationship between incident and output count rate of the analog front-end is explored under diagnostic imaging conditions for a promising poly-Si based design. The input to the amplifier is modeled in the time domain assuming a realistic input x-ray spectrum. Simulations of circuits based on poly-Si thin-film transistors are used to determine the resulting output count rate as a function of input count rate, energy discrimination threshold and operating conditions. |
| Databáze: | OpenAIRE |
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