Hybrid Pixel Detectors for Next-Generation Diffraction Cameras in Scanning Electron Microscopy

电子背散射衍射（EBSD）是一种扫描电子显微镜（SEM）技术，用于分析从纳米和微观到宏观水平的晶体材料的特性。它使用一个灵敏的相机来记录在样品上的一系列纳米级斑点上产生的电子后向散射衍射图（EBSP），因为它被聚焦的电子束“映射”。EBSD是许多领域研究和开发的重要工具，包括：冶金；半导体;和地质学。在许多EBSD实验中，分析的灵敏度和速度受到当前可用相机的限制，并且证明需要改进。相机灵敏度的提高将允许用较低的电子剂量捕获高质量的ebsp。开发更高灵敏度的EBSD相机将允许更高速度的操作，从而增强EBSD在所有应用中的吸引力。它将为学术界和工业界开辟新的兴趣领域，包括迄今为止尚未适用于EBSD的光束敏感材料。目前的EBSD相机使用间接电子检测（IeD），其灵敏度受到光子（由荧光粉屏幕上的电子产生）通过光学器件到图像传感器的低效耦合的限制。相反，图像传感器上的直接电子检测（DeD）（即去除低效的光学器件）可以提高灵敏度，并且可以通过使用混合像素检测器（HPD）来实现，该检测器包括一个半导体传感器，连接到电子计数专用集成电路（ASIC），例如Medipix家族中的那些。该项目旨在建立在我们早期工作的基础上，开发基于最新一代Medipx4 ASIC的HPD，针对EBSD进行了优化，并大大提高了灵敏度。”

"Electron Backscatter Diffraction (EBSD) is a Scanning Electron Microscopy (SEM) technique to analyse the properties of crystalline materials at scales from the nano- and micro-, up to the macroscopic level. It uses a sensitive camera to record the Electron Backscatter Diffraction Pattern (EBSP) generated at each of a series of nano-scale spots on a specimen as it is ""mapped"" by the focussed electron beam.EBSD is an important tool for research and development in many fields, including: metallurgy; semiconductors; and geology. In many EBSD experiments the sensitivity and speed of analysis is limited by the cameras currently available, and there is a demonstrated need for improvement. Increased sensitivity of the camera would allow for the capture of high-quality EBSPs with lower electron doses applied to the specimen. Development of a higher-sensitivity EBSD camera will allow for higher-speed operation and hence enhance the appeal of EBSD across all applications. It will open new areas of both academic and industrial interest, including for beam-sensitive materials that have not so far been amenable to EBSD.Current EBSD cameras use Indirect electron Detection (IeD) with sensitivity limited by inefficient coupling of photons (generated by electrons at a phosphor screen) via optics to the image sensor. Instead, Direct electron Detection (DeD) at the image sensor (i.e. removing the inefficient optics) can enhance sensitivity and may be realised by the use of a Hybrid Pixel Detector (HPD) comprising a semiconducting sensor bonded to an electron-counting Application Specific Integrated Circuit (ASIC) such as those in the Medipix family. The project seeks to build on our early work and develop an HPD based on latest-generation Medipx4 ASIC, optimised for EBSD and with substantially enhanced sensitivity."