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Van Dyck D

Publications and source records attributed to Van Dyck D.

6 recordsLinked to original sources
PubMed2000

Inelastic scattering and holography

The controversy about whether or not an inelastically scattered electron wave can still interfere with a reference wave is solved by treating the whole problem rigorously and describing electron, source and object in one Hamiltonian. It turns out that, in principle, interference can occur between an inelastically scattered wave and a reference wave from the incident beam spectrum provided the energy difference is smaller than about 10(-15) eV. However, it is argued that the density of states in source object and electron wave is much too small to make this effect observable.

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PubMed1999

Towards an exit wave in closed analytical form.

A simple but sufficiently accurate expression is obtained for the exit wave of a crystal in zone-axis orientation. The exit wave at each atom column can be parametrized with only one parameter, which is a function of the projected 'weight' of the column.

Journal Article↗
PubMed1999

How to optimize the design of a quantitative HREM experiment so as to attain the highest precision.

Using parameter estimation theory, an expression is derived for the maximum precision with which the position of a single atom can be estimated from high resolution transmission electron microscopy images. This expression, being a complicated function of the object as well as of the microscope parameters and the electron dose, can be used to optimize the design of an HREM experiment so as to attain the highest precision.

Journal Article↗
PubMed1998

Does Crystal Tilt Enhance the Electron Interaction?

: We have observed that a slight crystal tilt away from the zone axis paradoxically decreases the dynamical extinction length, as if the electron-crystal interaction increases. This effect disappears at larger tilt angles. Using the simplified channeling theory, this behavior is explained.

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PubMed1998

Desktop X-ray microscopy and microtomography.

Recent developments in X-ray microtomography have made it possible to miniaturize a CT scanner into a versatile and cost-effective desktop system that fits into any laboratory environment. The possibilities of the technique are demonstrated for a range of applications. It is also shown how an existing scanning electron microscope with an X-ray detector can, with a specially developed attachment, be transformed into an X-ray microscope and microtomograph.

Journal Article↗