Bidola Pidassa M, Zanette Irene, Achterhold Klaus, Holzner Christian, Pfeiffer Franz
Opt Express. 2015 Nov 16;23(23):30000-13. doi: 10.1364/OE.23.030000.
Single distance X-ray propagation-based phase-contrast imaging is considered as a simple method compared to those requiring additional precise instruments and sophisticated algorithms to retrieve phase images. It requires, however, a modicum of conditions within the setup which include partial coherence and small pixel size at the sample position. While these conditions are usually satisfied at synchrotron light sources, they are not always satisfied within laboratory setups. In fact, these setups are limited by the size of the polychromatic source that directly influences the partial coherence of the beam, the propagation distance and the photon flux. A prior knowledge of the sample refractive index, namely the ratio of delta (δ) and beta (β) values, are also essential for the phase retrieval but this method is powerful in the presence of noise compared to absorption-based imaging. An investigation of the feasibility and the efficient applicability of this method in a commercially available X-ray microscope is conducted in this work.
与那些需要额外精密仪器和复杂算法来获取相位图像的方法相比，基于单距离X射线传播的相衬成像被认为是一种简单的方法。然而，它需要在设置中有一些条件，包括部分相干性和样品位置处的小像素尺寸。虽然这些条件通常在同步辐射光源处得到满足，但在实验室设置中并不总是能满足。事实上，这些设置受到多色光源尺寸的限制，多色光源尺寸直接影响光束的部分相干性、传播距离和光子通量。样品折射率的先验知识，即δ值和β值的比值，对于相位恢复也是必不可少的，但与基于吸收的成像相比，这种方法在存在噪声的情况下很强大。这项工作对该方法在商用X射线显微镜中的可行性和有效适用性进行了研究。
