Probing the spatial coherence of soft X-ray beams with Fresnel mirrors at BL25SU of SPring-8
Probing the spatial coherence of soft X-ray beams with Fresnel mirrors at BL25SU of SPring-8
复制标题
使用 SPring-8 的 BL25SU 菲涅尔镜探测软 X 射线束的空间相干性
DOI：
10.1107/s1600577519002583
复制
发表时间：
2019
影响因子：
2.5
通讯作者：
and H. Mimura
中科院分区：
文献类型：
--
作者：
Y. Takeo;H. Motoyama;Y. Senba;H. Kishimoto;H. Ohashi;and H. Mimura
在设计用于同步辐射源和自由电子激光器的光束线的先进光学系统时，探测X射线的空间相干性变得越来越重要。不同狭缝宽度的双狭缝实验是定量测量包括X射线区域在内的宽波长范围内的空间相干性的典型方法。然而，这种方法不能用于空间相干性的分析时，两个评估点分开的毫米级的大距离，由于干涉条纹之间的间距非常窄。基于菲涅耳镜的光学系统可以通过使来自在横向方向上与X射线束分离的两个小镜的两个光束交叉来产生干涉图案。条纹间距可以通过反射镜上的入射角来控制。在SPring-8软X射线光束线（BL 25 SU）上搭建了一套菲涅耳反射镜光学系统，并利用该光束在300 eV处定量测量了垂直和水平方向的相干性与虚源尺寸之间的关系。 所得结果表明，这是一个有价值的方法，沿着光束线的光学系统的优化。
Probing the spatial coherence of X-rays has become increasingly important when designing advanced optical systems for beamlines at synchrotron radiation sources and free-electron lasers. Double-slit experiments at various slit widths are a typical method of quantitatively measuring the spatial coherence over a wide wavelength range including the X-ray region. However, this method cannot be used for the analysis of spatial coherence when the two evaluation points are separated by a large distance of the order of millimetres owing to the extremely narrow spacing between the interference fringes. A Fresnel-mirror-based optical system can produce interference patterns by crossing two beams from two small mirrors separated in the transverse direction to the X-ray beam. The fringe spacing can be controlled via the incidence angles on the mirrors. In this study, a Fresnel-mirror-based optical system was constructed at the soft X-ray beamline (BL25SU) of SPring-8. The relationship between the coherence and size of the virtual source was quantitatively measured at 300 eV in both the vertical and horizontal directions using the beam. The results obtained indicate that this is a valuable method for the optimization of optical systems along beamlines.