National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, United Kingdom.
Ultramicroscopy. 2011 Apr;111(5):320-9. doi: 10.1016/j.ultramic.2011.01.012. Epub 2011 Jan 18.
For precise orientation and strain measurements, advanced Electron Backscatter Diffraction (EBSD) techniques require both accurate calibration and reproducible measurement of the system geometry. In many cases the pattern centre (PC) needs to be determined to sub-pixel accuracy. The mechanical insertion/retraction, through the Scanning Electron Microscope (SEM) chamber wall, of the electron sensitive part of modern EBSD detectors also causes alignment and positioning problems and requires frequent monitoring of the PC. Optical alignment and lens distortion issues within the scintillator, lens and charge-coupled device (CCD) camera combination of an EBSD detector need accurate measurement for each individual EBSD system. This paper highlights and quantifies these issues and demonstrates the determination of the pattern centre using a novel shadow-casting technique with a precision of ∼10μm or ∼1/3 CCD pixel.
为了实现精确的取向和应变测量，先进的电子背散射衍射（EBSD）技术需要对系统几何形状进行精确校准和可重复的测量。在许多情况下，需要将花样中心（PC）确定到亚像素精度。现代 EBSD 探测器的电子敏感部分通过扫描电子显微镜（SEM）腔壁的机械插入/缩回也会导致对准和定位问题，并需要频繁监测 PC。EBSD 探测器的闪烁体、透镜和电荷耦合器件（CCD）相机组合内部的光学对准和透镜失真问题需要对每个单独的 EBSD 系统进行精确测量。本文强调并量化了这些问题，并展示了使用一种新颖的阴影投射技术确定花样中心的方法，其精度约为 10μm 或约 1/3 CCD 像素。
