<p>Beamline 6C Bio Medical Imaging at the Pohang Light Source-II is a station for synchrotron X-ray radiograph and micro-computed tomography. The beam emitted from a multipole wiggler is trimmed, attenuated, and made monochromatic before illuminating an object. The projection image is recorded using a detection scheme that converts the X-ray image into a visible light image, which is then magnified and captured by an optical microscope. For image conversion, a single-crystal (garnet) scintillation screen is used. Here, we assess the image quality in terms of noise characteristics and spatial resolutions. Two types of scintillation screens (LuAG:Ce and GAGG:Ce) with two different thicknesses (50 μm and 100 μm) are compared. Although GAGG:Ce featured a better signal-to-noise ratio thanks to its two times higher light yield, contrast-transfer function (CTF) analysis in the spatial frequency domain suggests that the spatial resolutions of each scintillator were more or less identical. A scientific CMOS (complementary metal-oxide semiconductor) camera at the beamline was seen to accumulate electronic noise for longer exposures. In addition, because each scintillator has similar resolution characteristics according to CTF results, the resolution according to the various sample-to-detector distances (i.e., SDD or magnification or <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40042_2025_1453_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">${R}_{2}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>R</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation>) in a particular LuAG:Ce scintillator was measured, and the optimal <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40042_2025_1453_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">${R}_{2}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>R</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation> was observed to be 50 mm.</p>

Characterization of scintillator performance for synchrotron-based radiography

期刊论文
发表日期：

2025年8月8日

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Jaehong Hwang,
Seob-Gu Kim,
Jae-Hong Lim,
Junwoo Kim

摘要

Beamline 6C Bio Medical Imaging at the Pohang Light Source-II is a station for synchrotron X-ray radiograph and micro-computed tomography. The beam emitted from a multipole wiggler is trimmed, attenuated, and made monochromatic before illuminating an object. The projection image is recorded using a detection scheme that converts the X-ray image into a visible light image, which is then magnified and captured by an optical microscope. For image conversion, a single-crystal (garnet) scintillation screen is used. Here, we assess the image quality in terms of noise characteristics and spatial resolutions. Two types of scintillation screens (LuAG:Ce and GAGG:Ce) with two different thicknesses (50 μm and 100 μm) are compared. Although GAGG:Ce featured a better signal-to-noise ratio thanks to its two times higher light yield, contrast-transfer function (CTF) analysis in the spatial frequency domain suggests that the spatial resolutions of each scintillator were more or less identical. A scientific CMOS (complementary metal-oxide semiconductor) camera at the beamline was seen to accumulate electronic noise for longer exposures. In addition, because each scintillator has similar resolution characteristics according to CTF results, the resolution according to the various sample-to-detector distances (i.e., SDD or magnification or ${R}_{2}$ $R_{2}$ ) in a particular LuAG:Ce scintillator was measured, and the optimal ${R}_{2}$ $R_{2}$ was observed to be 50 mm.