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摘要
We introduce the development of pixel-structured screens with a thallium-doped CsI (CsI:Tl) scintillator for indirect digital X-ray imaging sensors. The indirect-conversion detection method based on the pixel-structured CsI:Tl scintillator provides high spatial resolution X-ray imaging without sacrificing the light spread in thick scintillation layers. The scintillation screens were fabricated by using a vacuum deposition process and filling the CsI:Tl scintillating powders into a two-dimensional pixel-structured silicon array. Pixel structures with 100 pm and 50 mu m pixel sizes with wall widths of 20 mu m and 200 mu m thickness were prepared and the fabricated CsI:Tl scintillating powders were filled into the trench of the pixel structure through a vacuum process. The final scintillation screens with 2.5 cm x 2.5 cm size were prepared and directly coupled to a CCD image sensor with an optical lens for performance evaluation of X-ray imaging. The imaging performance of the samples was investigated in terms of the relative light intensity, the X-ray linearity and the spatial resolution under practical X-ray exposure conditions. These preliminary results imply that pixel-structured CsI:Tl scintillating screens show high spatial resolution by less lateral spread of the emitted visible photons within pixel-structured silicon arrays. However, these X-ray detectors still require improved X-ray sensitivity by coating the reflective layer onto an inner silicon wall surface and filling the scintillating power into pixel structures completely.
- 出版日期2011-12
