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). 2017 Jun 1;66(3):172-181. doi: 10.1093/jmicro/dfx002.
We have developed a real-time wave field reconstruction transmission electron microscope system that enables auto focus tracking at a video rate. In the developed system, a high-speed image calculation technique using a graphical processing unit was incorporated along with two techniques facilitating high-speed focus control using high-voltage modulation and weighted image integration using exposure time control. By utilizing these techniques, the sample drift induced in the Z-axis direction can be measured and automatically corrected for every 1/30 of a second. The auto focus tracking system can be operated in the sample drift range of ±150 nm with a precision of ~0.4 nm. In addition to amorphous samples, the system can be used to examine thin crystalline samples, which indicates that atomic structure analysis can be performed in real time with high reliability even when heavy drift occurs in the Z-axis direction.
我们开发了一种实时波场重建透射电子显微镜系统，该系统能够以视频速率进行自动聚焦跟踪。在所开发的系统中，结合了使用图形处理单元的高速图像计算技术以及两种有助于高速聚焦控制的技术，即利用高压调制的高速聚焦控制技术和利用曝光时间控制的加权图像积分技术。通过运用这些技术，可在每1/30秒的时间内测量并自动校正Z轴方向上引起的样品漂移。自动聚焦跟踪系统能够在±150 nm的样品漂移范围内运行，精度约为0.4 nm。除了非晶态样品外，该系统还可用于检查薄晶体样品，这表明即使在Z轴方向发生严重漂移时，也能够以高可靠性实时进行原子结构分析。
