NANOESCA - ELECTRON SPECTROSCOPY FOR CHEMICAL ANALYSIS IMAGED AT THE NANOSCALE.

NanoESCA是一种超高真空（UHV）光电发射光谱系统，具有亚微米空间分辨率，可从几微米的平坦材料表面进行实空间和k空间（倒易空间）映射，并能够在纳米级进行定量化学状态映射。该系统设计用于安装在同步加速器光束线终端站或纳米科学实验室中。该系统具有多种操作模式。UV光子源用于紫外光电子能谱（UPS）、角分辨UPS和光电子发射显微镜（PEEM），软X射线用于X射线光电子能谱（XPS）。UPS给出了关于弱束缚态和真实的空间中的价带结构以及k空间中的表面电子能带结构的能量过滤信息。XPS用于探测芯能级光谱以获得关于表面的化学组成的定量信息。与高分辨率扫描电子显微镜相比，PEEM直接对发射光电子的表面区域进行真实的成像，而无需扫描。通过能量滤波PEEM图像，可以获得表面功函数的定量图。视场可从毫米到微米进行调节，可对小至30 nm（UPS模式）和480 nm（XPS模式）的特征进行高分辨率成像。所要求的NanoESCA机器代表了成像和光谱PEEM的下一代。它使用了已建立的平行成像技术的扩展，通过使用双半球形（像差校正）电子分析器与高光子通量真空紫外和X射线源相结合，以实现真实的空间和k空间中的纳米尺度成像和光谱学;后一种模式允许关于材料的电子能带结构的信息被可视化并直接与理论模型进行比较。独特的是，这种使用X射线或VUV源获得纳米级光谱的能力是通过相同的PEEM“柱”并行成像获得的，该PEEM“柱”也用作成像光谱仪的入口透镜。

The NanoESCA is an Ultra High Vacuum (UHV) photoemission spectroscopy system with sub-micron spatial resolution for real-space and k-space (reciprocal space) mapping from areas of a few microns of flat material surfaces, and the capability to perform quantitative chemical state mapping at the nanoscale. The system is designed for installation on a synchrotron beam line end-station or in a Nano Science Laboratory.The system has various modes of operation. UV photon sources are used for Ultra-violet Photoemission Spectroscopy (UPS), Angle Resolved UPS, and Photo Emission Electron Microscopy (PEEM), soft X-rays are used for X-ray Photoemission Spectroscopy (XPS). UPS gives energy filtered information on weakly bound states and the valence band structure in real space and the surface electronic band structure in k-space. XPS is used to probe core level spectra to obtain quantitative information on the chemical composition of a surface. In contrast to the high resolution Scanning Electron Microscope, PEEM directly images surface areas emitting photoelectrons in real time without scanning. By energy filtering PEEM images it is possible to obtain quantitative maps of surface work function. The field of view is adjustable from millimetres to microns allowing high resolution imaging of features as small as 30nm (UPS modes) and 480nm (XPS mode).The NanoESCA machine being requested represents the next generation in imaging and spectroscopic PEEM. It uses an extension of the established parallel imaging technique, to simultaneously image and filter photoelectrons, by using a double hemispherical (aberration corrected) electron analyser in combination with high photon flux VUV and X-ray sources, to realise nano scale imaging and spectroscopy in real space and in k-space; the latter mode allows information on the electronic band structure of materials to be visualised and compared directly with theoretical models. Uniquely, this capability to obtain nanoscale spectroscopy using either X-ray or VUV sources is obtained by parallel imaging through the same PEEM 'column' which also acts as the entrance lens of the imaging spectrometer.