Department of Physics, University of Alberta, Edmonton, Alberta, Canada.
Ultramicroscopy. 2013 Jun;129:42-52. doi: 10.1016/j.ultramic.2013.02.021. Epub 2013 Mar 15.
We developed a new method for characterization of detector performance used in the transmission electron microscope (TEM) based on the measured contrast of holographic fringes. The new method changes spatial frequency of the measured holographic fringes, generated by an electrostatic biprism and Schottky or cold field-emission gun, to sample the modulation-transfer function (MTF) of the detector. The MTF of a Gatan Ultrascan™ 1000 charged-coupled detector (CCD) is evaluated using the new method and the results are compared to the established noise and slanted-edge method results. Requirements for accuracy of the edge and noise MTF methods are discussed. We consider issues surrounding incomplete read-out and how it affects the gain reference normalization of the detector. We evaluate how the MTF affects optimization of experimental parameters in the TEM.
我们开发了一种基于测量全息条纹对比度的新方法来描述透射电子显微镜（TEM）中使用的探测器性能。该新方法改变了由静电双棱镜和肖特基或冷场发射枪产生的测量全息条纹的空间频率，以对探测器的调制传递函数（MTF）进行采样。使用新方法评估了 Gatan Ultrascan™ 1000 电荷耦合探测器（CCD）的 MTF，并将结果与已建立的噪声和倾斜边缘方法的结果进行了比较。讨论了边缘和噪声 MTF 方法的精度要求。我们考虑了不完整读出的问题以及它如何影响探测器的增益参考归一化。我们评估了 MTF 如何影响 TEM 中实验参数的优化。
