The fractional Talbot effect in differential x-ray phase-contrast imaging for extended and polychromatic x-ray sources
The fractional Talbot effect in differential x-ray phase-contrast imaging for extended and polychromatic x-ray sources
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DOI：
10.1111/j.1365-2818.2008.02072.x
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发表时间：
2008-10-01
影响因子：
2
通讯作者：
Pfeiffer, F.
中科院分区：
文献类型：
--
作者：
Engelhardt, M.;Kottler, C.;Pfeiffer, F.
利用基于菲涅耳衍射理论的数值模拟方法，讨论了光源尺寸和能谱等物理参数对用于相衬成像的光栅干涉仪性能的影响。给出的模拟结果解释了为什么在最近的实验中，干涉仪可以很好地与实验室多色X射线源相结合。此外，还表明干涉仪的两个光栅之间的距离一般不受光子能谱宽度的限制。这意味着可以设计出为相位测量提供进一步改善图像质量的干涉仪，因为可以通过增大该距离来增加用于相位测量的主测量信号。最后，给出了定量评价多色X射线源测量数据的数学背景和实际指导。
The influence of different physical parameters, such as the source size and the energy spectrum, on the functional capability of a grating interferometer applied for phase-contrast imaging is discussed using numerical simulations based on Fresnel diffraction theory. The presented simulation results explain why the interferometer could be well combined with polychromatic laboratory x-ray sources in recent experiments. Furthermore, it is shown that the distance between the two gratings of the interferometer is not in general limited by the width of the photon energy spectrum. This implies that interferometers that give a further improved image quality for phase measurements can be designed, because the primary measurement signal for phase measurements can be increased by enlargement of this distance. Finally, the mathematical background and practical instructions for the quantitative evaluation of measurement data acquired with a polychromatic x-ray source are given.