The effect of a variable focal spot size on the contrast channels retrieved in edge-illumination X-ray phase contrast imaging.
The effect of a variable focal spot size on the contrast channels retrieved in edge-illumination X-ray phase contrast imaging.
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DOI：
10.1038/s41598-022-07376-0
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发表时间：
2022-03-01
影响因子：
4.6
通讯作者：
Olivo A
中科院分区：
文献类型：
--
作者：
Astolfo A;Buchanan I;Partridge T;Kallon GK;Hagen CK;Munro PRT;Endrizzi M;Bate D;Olivo A
多模态 X 射线成像可以提取相位图像和暗场（或“超小角度散射”）图像以及传统的衰减图像。最近，不同的小组已经开发了使用传统源的基于扫描的系统，可以同时在相对大尺寸的物体上输出上述三个图像。一个限制是需要一定程度的空间相干性，这可以通过使用微焦源或通过在扩展源前面放置吸收光栅来实现。这两种解决方案都限制了可用于成像的通量，后者还导致更复杂的设置和额外的对准要求。边缘照明部分克服了这一问题，因为事实证明它可以处理高达 100 微米的焦点。虽然高通量 100 微米焦点源确实存在，但其相对较大的占地面积和较高的成本可能会阻碍广泛转化。一个简单的解决方案是在大焦斑源前面放置一个狭缝。我们使用可调狭缝来研究系统在各种有效焦斑尺寸下的性能，通过提取相同样本在一系列狭缝宽度下的透射、相位和暗场图像。我们表明，对于不同的 X 射线统计数据和有效焦点尺寸，可以获得一致、可重复的结果。随着狭缝宽度的增加，可以观察到原始微分相位峰的预期减少，并通过扩大的灵敏度函数在检索过程中进行补偿。这会导致正确检索到相同的值，但误差条稍大，即相位灵敏度降低。同时，还观察到暗场信号略有增加。
Multi-modal X-ray imaging allows the extraction of phase and dark-field (or “Ultra-small Angle Scatter”) images alongside conventional attenuation ones. Recently, scan-based systems using conventional sources that can simultaneously output the above three images on relatively large-size objects have been developed by various groups. One limitation is the need for some degree of spatial coherence, achieved either through the use of microfocal sources, or by placing an absorption grating in front of an extended source. Both these solutions limit the amount of flux available for imaging, with the latter also leading to a more complex setup with additional alignment requirements. Edge-illumination partly overcomes this as it was proven to work with focal spots of up to 100 micron. While high-flux, 100 micron focal spot sources do exist, their comparatively large footprint and high cost can be obstacles to widespread translation. A simple solution consists in placing a single slit in front of a large focal spot source. We used a tunable slit to study the system performance at various effective focal spot sizes, by extracting transmission, phase and dark-field images of the same specimens for a range of slit widths. We show that consistent, repeatable results are obtained for varying X-ray statistics and effective focal spot sizes. As the slit width is increased, the expected reduction in the raw differential phase peaks is observed, compensated for in the retrieval process by a broadened sensitivity function. This leads to the same values being correctly retrieved, but with a slightly larger error bar i.e. a reduction in phase sensitivity. Concurrently, a slight increase in the dark-field signal is also observed.
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影响因子：
8.6
作者：
Endrizzi, M.;Vittoria, F. A.;Olivo, A.
通讯作者：
Olivo, A.
影响因子：
3.4
作者：
Kallon, G. K.;Vittoria, F. A.;Olivo, A.
通讯作者：
Olivo, A.
影响因子：
3.8
作者：
Endrizzi, Marco;Vittoria, Fabio A.;Olivo, Alessandro
通讯作者：
Olivo, Alessandro
影响因子：
3.8
作者：
Modregger, P.;Pinzer, B. R.;Stampanoni, M.
通讯作者：
Stampanoni, M.
在光栅干涉仪中的暗场对比度和粒度选择性的解释。
影响因子：
1.9
作者：
Lynch SK;Pai V;Auxier J;Stein AF;Bennett EE;Kemble CK;Xiao X;Lee WK;Morgan NY;Wen HH
通讯作者：
Wen HH