Valdivia M P, Stutman D, Finkenthal M
Appl Opt. 2015 Apr 1;54(10):2577-83. doi: 10.1364/AO.54.002577.
The Talbot-Lau x-ray moiré deflectometer is a powerful plasma diagnostic capable of delivering simultaneous refraction and attenuation information through the accurate detection of x-ray phase shift and intensity. The diagnostic can provide the index of refraction n=1-δ+iβ of an object (dense plasma, for example) placed in the x-ray beam by independently measuring both δ and β, which are directly related to the electron density n(e) and the attenuation coefficient μ, respectively. Since δ and β depend on the effective atomic number Z(eff), a map can be obtained from the ratio between phase and absorption images acquired in a single shot. The Talbot-Lau x-ray moiré deflectometer and its corresponding data acquisition and processing are briefly described to illustrate how the above is achieved; Z(eff) values of test objects within the 4-12 range were obtained experimentally through simultaneous refraction and attenuation measurements. We show that Z(eff) mapping of objects does not require previous knowledge of sample length or shape. The determination of Z(eff) from refraction and attenuation measurements with moiré deflectometry could be of high interest to various domains of high energy density research, such as shocked materials and inertial confinement fusion experiments, as well as material science and nondestructive testing.
塔尔博特-劳x射线莫尔偏折仪是一种强大的等离子体诊断设备,能够通过精确检测x射线相移和强度来同时提供折射和衰减信息。该诊断设备可以通过独立测量δ和β来提供置于x射线束中的物体(例如高密度等离子体)的折射率n = 1 - δ + iβ,其中δ和β分别与电子密度n(e)和衰减系数μ直接相关。由于δ和β取决于有效原子序数Z(eff),因此可以从单次采集的相位图像与吸收图像的比值中获得一张图谱。简要描述了塔尔博特-劳x射线莫尔偏折仪及其相应的数据采集和处理过程,以说明上述目标是如何实现的;通过同时进行折射和衰减测量,实验获得了4至12范围内测试物体的Z(eff)值。我们表明,物体的Z(eff)映射不需要预先了解样品的长度或形状。利用莫尔偏折术通过折射和衰减测量来确定Z(eff),对于高能密度研究的各个领域可能具有很高的价值,例如冲击材料和惯性约束聚变实验,以及材料科学和无损检测。