School of Physics and Astronomy, Monash University, Clayton, VIC, 3800, Australia.
Sci Rep. 2023 Jul 7;13(1):11001. doi: 10.1038/s41598-023-37334-3.
The size of the smallest detectable sample feature in an x-ray imaging system is usually restricted by the spatial resolution of the system. This limitation can now be overcome using the diffusive dark-field signal, which is generated by unresolved phase effects or the ultra-small-angle x-ray scattering from unresolved sample microstructures. A quantitative measure of this dark-field signal can be useful in revealing the microstructure size or material for medical diagnosis, security screening and materials science. Recently, we derived a new method to quantify the diffusive dark-field signal in terms of a scattering angle using a single-exposure grid-based approach. In this manuscript, we look at the problem of quantifying the sample microstructure size from this single-exposure dark-field signal. We do this by quantifying the diffusive dark-field signal produced by 5 different sizes of polystyrene microspheres, ranging from 1.0 to 10.8 µm, to investigate how the strength of the extracted dark-field signal changes with the sample microstructure size, [Formula: see text]. We also explore the feasibility of performing single-exposure dark-field imaging with a simple equation for the optimal propagation distance, given microstructure with a specific size and thickness, and show consistency between this model and experimental data. Our theoretical model predicts that the dark-field scattering angle is inversely proportional to [Formula: see text], which is also consistent with our experimental data.
X 射线成像系统中最小可检测样本特征的大小通常受到系统空间分辨率的限制。现在，通过使用漫散射暗场信号可以克服这一限制，该信号是由未解析的相位效应或来自未解析样本微观结构的超小角度 X 射线散射产生的。对这种暗场信号的定量测量对于医学诊断、安全检查和材料科学中揭示微观结构尺寸或材料特性非常有用。最近，我们提出了一种新的方法，通过单次曝光网格方法，用散射角来量化漫散射暗场信号。在本文中，我们研究了从这种单次曝光暗场信号中定量确定样本微观结构尺寸的问题。我们通过量化由 5 种不同尺寸的聚苯乙烯微球产生的漫散射暗场信号来实现这一点，尺寸范围从 1.0 到 10.8μm，以研究提取的暗场信号强度如何随样本微观结构尺寸而变化，[公式：见文本]。我们还探讨了使用特定尺寸和厚度的微观结构的简单方程来执行单次曝光暗场成像的可行性，并展示了该模型与实验数据之间的一致性。我们的理论模型预测暗场散射角与[公式：见文本]成反比，这与我们的实验数据也一致。
