Diffraction contrast imaging using virtual apertures

Author(s)
Christoph Gammer, V. Burak Ozdol, Christian H. Liebscher, Andrew M. Minor
Abstract

Two methods on how to obtain the full diffraction information from a sample region and the associated reconstruction of images or diffraction patterns using virtual apertures are demonstrated. In a STEM-based approach, diffraction patterns are recorded for each beam position using a small probe convergence angle. Similarly, a tilt series of TEM dark-field images is acquired. The resulting datasets allow the reconstruction of either electron diffraction patterns, or bright-, dark- or annular dark-field images using virtual apertures. The experimental procedures of both methods are presented in the paper and are applied to a precipitation strengthened and creep deformed ferritic alloy with a complex microstructure. The reconstructed virtual images are compared with conventional TEM images. The major advantage is that arbitrarily shaped virtual apertures generated with image processing software can be designed without facing any physical limitations. In addition, any virtual detector that is specifically designed according to the underlying crystal structure can be created to optimize image contrast.

Organisation(s)
Physics of Nanostructured Materials
External organisation(s)
Lawrence Berkeley National Laboratory, University of California, Berkeley
Journal
Ultramicroscopy
Volume
155
Pages
1-10
No. of pages
10
ISSN
0304-3991
DOI
https://doi.org/10.1016/j.ultramic.2015.03.015
Publication date
08-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Instrumentation, Atomic and Molecular Physics, and Optics
Portal url
https://ucrisportal.univie.ac.at/en/publications/diffraction-contrast-imaging-using-virtual-apertures(227ddbba-e898-4203-89d5-17d2fc654d6c).html