Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5466662 | Ultramicroscopy | 2017 | 10 Pages |
Abstract
A relatively simple yet accurate analytical model for the image formation in the imaging scanning TEM (ISTEM) imaging mode, which implements partial spatial incoherence using a combination of scanning illumination and conventional imaging, is presented. Based on an object function approximation the ISTEM intensity can be divided into a constant, a linear and a nonlinear term. Under certain conditions, which are discussed, the formation of both linear and nonlinear terms can be expressed by convolutions with point spread functions. A closer inspection of these allows an insight into the advantages of ISTEM compared to conventional TEM (CTEM). The findings of the proposed model are confirmed by comparison to multislice simulations. A close investigation of the linear coherent contrast transfer function allows the derivation of optimal imaging conditions to reach a maximum resolution for a given signal-to-noise ratio. The robustness of ISTEM towards temporal incoherence is finally demonstrated and discussed within the model.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Florian F. Krause, Andreas Rosenauer, Dirk Van Dyck,