Yang Xiaowei, Wang Hongchang, Hand Matthew, Sawhney Kawal, Kaulich Burkhard, Kozhevnikov Igor V, Huang Qiushi, Wang Zhanshan
MOE Key Laboratory of Advanced Micro-Structured Materials, Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China.
Diamond Light Source Ltd, Harwell Science and Inovation Campus, Didcot OX11 0DE, UK.
J Synchrotron Radiat. 2017 Jan 1;24(Pt 1):168-174. doi: 10.1107/S1600577516017884.
Collimated plane-grating monochromators (cPGMs), consisting of a plane mirror and plane diffraction grating, are essential optics in synchrotron radiation sources for their remarkable flexibility and good optical characteristics in the soft X-ray region. However, the poor energy transport efficiency of a conventional cPGM (single-layer-coated) degrades the source intensity and leaves reduced flux at the sample, especially for the tender X-ray range (1-4 keV) that covers a large number of K- and L-edges of medium-Z elements, and M-edges of high-Z elements. To overcome this limitation, the use of a multilayer-based cPGM is proposed, combining a multilayer-coated plane mirror with blazed multilayer gratings. With this combination, the effective efficiency of cPGMs can be increased by an order of magnitude compared with the conventional single-layer cPGMs. In addition, higher resolving power can be achieved with improved efficiency by increasing the blaze angle and working at higher diffraction order.
准直平面光栅单色仪（cPGM）由平面镜和平面衍射光栅组成，由于其在软X射线区域具有出色的灵活性和良好的光学特性，是同步辐射源中的关键光学元件。然而，传统的cPGM（单层镀膜）能量传输效率低，会降低光源强度并使样品处的通量减少，特别是对于覆盖大量中Z元素的K边和L边以及高Z元素的M边的嫩X射线范围（1 - 4 keV）而言。为克服这一限制，有人提出使用基于多层膜的cPGM，即将多层镀膜平面镜与闪耀多层光栅相结合。通过这种组合，与传统的单层cPGM相比，cPGM的有效效率可提高一个数量级。此外，通过增加闪耀角并在更高衍射级下工作，可以在提高效率的同时实现更高的分辨率。
