CCD CAMERA CHARACTERIZATION FOR 400 KEV ELECTRON MICROSCOPY

以葡萄糖包埋的紫膜为测试标本， 400kV点扫测相可靠性的评估 由Gatan制造的1024x1024慢扫描CCD相机获取的图像。 之所以选择这个标本，是因为它代表了一个广泛的类别 低对比度辐射敏感生物体及其结构 已经很有名气了。计算的反射幅度来自 这些图像受到调制传递函数的强烈抑制 摄像机的镜头。尽管如此，它们的相位平均为&lt； 12-与恒基的参考数据不同，最高可达8.8 分辨率，相当于Nyquist频率的0.8 摄影机。用不同的相机也能观察到类似的结果 由Tietz制造，带有100千伏电子。这些结果证实了电荷耦合器件 照相机可以是可替代照相的可行记录介质 用于记录紫色等结晶样品的图像的胶片 薄膜。

Glucose-embedded purple membranes were used as a test specimen to evaluate the reliability of phases retrieved from 400 kV spot-scan images acquired on a 1024x1024 slow-scan CCD camera made by Gatan. This specimen was chosen because it represents a broad class of low-contrast radiation-sensitive biological objects and its structure is well established. The amplitudes of computed reflections from these images were strongly damped by the modulation transfer function of the camera. Nevertheless, their phases on average were < 12-different from the reference data of Henderson up to 8.8
resolution, which corresponds to 0.8 of the Nyquist frequency of the camera. Similar results are also observed with a different camera made by Tietz with 100 kV electrons. These results confirm that CCD camera can be a viable recording medium that can replace photographic film for recording images of crystalline specimens such as purple membrane.