FEI Company, P.O. Box 80066, 5600 KA Eindhoven, The Netherlands.
Ultramicroscopy. 2012 Mar;114:72-81. doi: 10.1016/j.ultramic.2012.01.008. Epub 2012 Jan 25.
Chromatic aberration limits the resolution in spherical-aberration corrected Transmission Electron Microscopy to approximately 0.7Å at 300 kV. The energy spread in the beam is the main contribution to the chromatic aberration. This spread can be reduced with a monochromator. Another limitation to the resolution in TEM can be the finite brightness of the source and the consequent partial spatial coherence of the illumination. This limitation becomes important when spherical aberration and/or defocus are present such as in uncorrected TEM or in focal-series reconstruction in TEM. We used a monochromator optimized for minimum brightness loss and a prototype 'high-brightness' gun, and obtained brightness after monochromation comparable to that of the standard Schottky FEG before monochromation. The images were acquired on the prototype TEAM 0.5 microscope, which was developed on a Titan platform by increasing its electrical and mechanical stability.
在 300kV 时，球差校正的透射电子显微镜的分辨率受色差限制，约为 0.7Å。束流的能量弥散是色差的主要贡献。这种弥散可以用单色器来减小。TEM 分辨率的另一个限制因素是光源的有限亮度和照明的部分空间相干性。当存在球差和/或散焦时，例如在未校正的 TEM 或 TEM 的焦面系列重建中，这种限制变得很重要。我们使用了一个针对最小亮度损失进行了优化的单色器和一个原型“高亮度”枪，并在单色化后获得了与未单色化前的标准肖特基 FEG 相当的亮度。这些图像是在原型 TEAM 0.5 显微镜上采集的，该显微镜是在 Titan 平台上开发的，通过提高其电气和机械稳定性。
