Tusche Christian, Chen Ying-Jiun, Schneider Claus M, Kirschner Jürgen
Forschungszentrum Jülich, Peter Grünberg Institut (PGI-6), Jülich 52425, Germany; Fakultät für Physik, Universität Duisburg-Essen, Duisburg 47057, Germany.
Forschungszentrum Jülich, Peter Grünberg Institut (PGI-6), Jülich 52425, Germany; Fakultät für Physik, Universität Duisburg-Essen, Duisburg 47057, Germany.
Ultramicroscopy. 2019 Nov;206:112815. doi: 10.1016/j.ultramic.2019.112815. Epub 2019 Jul 8.
Hemispherical deflection analyzers are the most widely used energy filters for state-of-the-art electron spectroscopy. Due to the high spherical symmetry, they are also well suited as imaging energy filters for electron microscopy. Here, we review the imaging properties of hemispherical deflection analyzers with emphasis on the application for cathode lens microscopy. In particular, it turns out that aberrations, in general limiting the image resolution, cancel out at the entrance and exit of the analyzer. This finding allows more compact imaging energy filters for momentum microscopy or photoelectron emission microscopy. For instance, high resolution imaging is possible, using only a single hemisphere. Conversely, a double pass hemispherical analyzer can double the energy dispersion, which means it can double the energy resolution at certain transmission, or can multiply the transmission at certain energy resolution.
半球形偏转分析仪是用于先进电子能谱的应用最为广泛的能量过滤器。由于具有高度的球对称性，它们也非常适合用作电子显微镜的成像能量过滤器。在此，我们回顾半球形偏转分析仪的成像特性，重点关注其在阴极透镜显微镜中的应用。特别地，结果表明，通常会限制图像分辨率的像差在分析仪的入口和出口处相互抵消。这一发现使得用于动量显微镜或光电子发射显微镜的成像能量过滤器能够更加紧凑。例如，仅使用单个半球就可以实现高分辨率成像。相反，双通半球形分析仪可以使能量色散加倍，这意味着在特定透射率下它可以使能量分辨率加倍，或者在特定能量分辨率下可以使透射率提高一倍。
