Optimizing experimental parameters for the projection requirement in HAADF-STEM tomography
Autor: | Zhichao Zhong, Kees Joost Batenburg, Richard Aveyard, Bernd Rieger |
---|---|
Přispěvatelé: | Centrum Wiskunde & Informatica, Amsterdam (CWI), The Netherlands |
Rok vydání: | 2017 |
Předmět: |
HAADF
Microscope Computer science 02 engineering and technology 01 natural sciences Signal Projection (linear algebra) law.invention law 0103 physical sciences Multislice 010306 general physics Tomography Instrumentation Tomographic reconstruction Linearity STEM 021001 nanoscience & nanotechnology Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Crystallography Transmission (telecommunications) Projection requirement 0210 nano-technology Algorithm Simulation |
Zdroj: | Ultramicroscopy, 177, 84-90 Ultramicroscopy, 177 |
ISSN: | 0304-3991 |
DOI: | 10.1016/j.ultramic.2017.03.009 |
Popis: | Tomographic reconstruction algorithms offer a means by which a tilt-series of transmission images can be combined to yield a three dimensional model of the specimen. Conventional reconstruction algorithms assume that the measured signal is a linear projection of some property, typically the density, of the material. Here we report the use of multislice simulations to investigate the extent to which this assumption is met in HAADF-STEM imaging. The use of simulations allows for a systematic survey of a range of materials and microscope parameters to inform optimal experimental design. Using this approach it is demonstrated that the imaging of amorphous materials is in good agreement with the projection assumption in most cases. Images of crystalline specimens taken along zone-axes are found to be poorly suited for conventional linear reconstruction algorithms due to channelling effects which produce enhanced intensities compared with off-axis images, and poor compliance with the projection requirement. Off-axis images are found to be suitable for reconstruction, though they do not strictly meet the linearity requirement in most cases. It is demonstrated that microscope parameters can be selected to yield improved compliance with the projection requirement. |
Databáze: | OpenAIRE |
Externí odkaz: |