Feja B, Aebi U
Maurice E. Müller Institute for Microscopy, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
J Microsc. 1999 Jan;193(1):15-19. doi: 10.1046/j.1365-2818.1999.00436.x.
The inelastic mean free path of 120 keV electrons in vitrified ice layers has been determined in an energy-filtering TEM. From the ratio of the unfiltered and zero-loss-filtered image intensities recorded with a slow-scan CCD camera, the relative sample thickness t/Lambda can be calculated. For calibration, the geometric ice thickness was measured by imaging a tilted view of a cylindrical hole which had been burnt into the ice layer. The total inelastic mean free path was found to be 161 nm, and the partial inelastic mean free path for an acceptance angle of 4.2 mrad was 232 nm. These results were built into a standard protocol for use in cryo-electron microscopy allowing on-line measurements of local ice-layer thicknesses by zero-loss-filtered/unfiltered imaging.
在能量过滤透射电子显微镜中测定了120 keV电子在玻璃态冰层中的非弹性平均自由程。根据用慢扫描电荷耦合器件相机记录的未过滤图像强度与零损失过滤图像强度的比值，可以计算出相对样品厚度t/Λ。为了进行校准，通过对烧蚀在冰层中的圆柱形孔的倾斜视图成像来测量几何冰厚度。发现总的非弹性平均自由程为161 nm，接受角为4.2 mrad时的部分非弹性平均自由程为232 nm。这些结果被纳入低温电子显微镜的标准协议中，允许通过零损失过滤/未过滤成像在线测量局部冰层厚度。
