A ray tracing method for predicting contrast in neutral atom beam imaging.
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Publication Date
2018-10Journal Title
Micron (Oxford, England : 1993)
ISSN
0968-4328
Publisher
Elsevier
Volume
113
Pages
61-68
Language
eng
Type
Article
Physical Medium
Print-Electronic
Metadata
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Lambrick, S., Bergin, M., Jardine, A., & Ward, D. (2018). A ray tracing method for predicting contrast in neutral atom beam imaging.. Micron (Oxford, England : 1993), 113 61-68. https://doi.org/10.1016/j.micron.2018.06.014
Abstract
A ray tracing method for predicting contrast in atom beam imaging is presented. Bespoke computational tools have
been developed to simulate the classical trajectories of atoms through the key elements of an atom beam microscope, as
described using a triangulated surface mesh, using a combination of MATLAB and C code. These tools enable simulated
images to be constructed that are directly analogous to the experimental images formed in a real microscope. It is then
possible to understand which mechanisms contribute to contrast in images, with only a small number of base assumptions
about the physics of the instrument. In particular, a key benefit of ray tracing is that multiple scattering effects can be
included, which cannot be incorporated easily in analytic integral models. The approach has been applied to model the
sample environment of the Cambridge scanning helium microscope (SHeM), a recently developed neutral atom pinhole
microscope. We describe two applications; (i) understanding contrast and shadowing in images; and (ii) investigation
of changes in image formation with pinhole-to-sample working distance. More generally the method has a broad range
of potential applications with similar instruments, including understanding imaging from different sample topographies,
refinement of a particular microscope geometry to enhance specific forms of contrast, and relating scattered intensity
distributions to experimental measurements.
Sponsorship
Mathworks Ltd.
Funder references
EPSRC (EP/R008272/1)
EPSRC (1820019)
EPSRC (1491971)
Identifiers
External DOI: https://doi.org/10.1016/j.micron.2018.06.014
This record's URL: https://www.repository.cam.ac.uk/handle/1810/280517