1992    
1993    
1994    
1995    
1996    
1997    
1998    
1999    
2000    
2001    
2002    
2003    
2004    
2005    
2006    
2007    
2008    
2009    
2010    
2011    
2012    
2013    
2014    
2015    
2016    
Tusche, Christian, Chen, Ying-Jiun, Schneider, Claus M., Kirschner, Jürgen

Imaging properties of hemispherical electrostatic energy analyzers for high resolution momentum microscopy
Ultramicroscopy 206, pp 112815/1-9 (2019)
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.