Tamura Takahiro, Kimura Yoshihide, Takai Yoshizo
Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Microscopy (Oxf). 2018 Feb 1;67(1):37-45. doi: 10.1093/jmicro/dfx127.
In this study, a function for the correction of coma aberration, 3-fold astigmatism and real-time correction of 2-fold astigmatism was newly incorporated into a recently developed real-time wave field reconstruction TEM system. The aberration correction function was developed by modifying the image-processing software previously designed for auto focus tracking, as described in the first article of this series. Using the newly developed system, the coma aberration and 3-fold astigmatism were corrected using the aberration coefficients obtained experimentally before the processing was carried out. In this study, these aberration coefficients were estimated from an apparent 2-fold astigmatism induced under tilted-illumination conditions. In contrast, 2-fold astigmatism could be measured and corrected in real time from the reconstructed wave field. Here, the measurement precision for 2-fold astigmatism was found to be ±0.4 nm and ±2°. All of these aberration corrections, as well as auto focus tracking, were performed at a video frame rate of 1/30 s. Thus, the proposed novel system is promising for quantitative and reliable in situ observations, particularly in environmental TEM applications.
在本研究中，一种用于校正彗差、三倍像散以及实时校正两倍像散的功能被新纳入到最近开发的实时波场重建透射电子显微镜（TEM）系统中。如本系列第一篇文章所述，像差校正功能是通过修改先前为自动聚焦跟踪设计的图像处理软件而开发的。使用新开发的系统，在进行处理之前，利用实验获得的像差系数对彗差和三倍像散进行校正。在本研究中，这些像差系数是从倾斜照明条件下产生的表观两倍像散中估算出来的。相比之下，两倍像散可以从重建的波场中实时测量和校正。在此，发现两倍像散的测量精度为±0.4纳米和±2°。所有这些像差校正以及自动聚焦跟踪均以1/30秒的视频帧率进行。因此，所提出的新型系统对于定量和可靠的原位观察具有前景，特别是在环境透射电子显微镜应用中。
