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Proceedings Paper

Resolution enhancement and performance characteristics of large-area a-Si:H x-ray imager with a high-aspect-ratio SU-8 micromold
Author(s): Ye Zhou; Alfredo Avila-Munoz; Sheng Tao; Zhihua Gu; Arokia Nathan; John A. Rowlands
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Paper Abstract

Hydrogenated amorphous silicon is known for its large area imaging applications because of its high photoconductivity and high absorption coefficient in the visible light range. This material can be also applied to X-ray imaging when coupled with a uniform scintillation (e.g. Gd2O2S phosphor) film integrated on top of a 2-D detection array. A thick phosphor layer is the prerequisite for high X-ray conversion efficiency. In reality, however, there may be significant crosstalk between adjacent pixels thus undermining spatial resolution. This paper introduces a high aspect ratio microstructure with the new photoresist SU-8 epoxy, which limits the phosphor to regions above the photodiodes. The differences between the above scheme and that of a continuous phosphor layer are compared in terms of the absorption efficiency, the conversion efficiency, and the modulation transfer function (MTF). The measurements are carried out in a medical testing environment with X-ray source voltages of 40-120kVp. The results show a great improvement in the spatial resolution.

Paper Details

Date Published: 30 August 2002
PDF: 10 pages
Proc. SPIE 4925, Electronic Imaging and Multimedia Technology III, (30 August 2002); doi: 10.1117/12.481582
Show Author Affiliations
Ye Zhou, Univ. of Waterloo (Canada)
Alfredo Avila-Munoz, Univ. of Waterloo (Canada)
Sheng Tao, Univ. of Waterloo (Canada)
Zhihua Gu, Univ. of Waterloo (Canada)
Arokia Nathan, Univ. of Waterloo (Canada)
John A. Rowlands, Univ. of Toronto (Canada)


Published in SPIE Proceedings Vol. 4925:
Electronic Imaging and Multimedia Technology III
LiWei Zhou; Chung-Sheng Li; Yoshiji Suzuki, Editor(s)

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