Channeling effects in electron diffraction describes the concentration of the electron on the atomic columns. These effects are important when crystals are imaged along high symmetry [uvw] zone axis. They are calculated using the Bloch-wave method described here.
It consists to create a stack of either the wave-functions intensity or the integrated intensity of the wave-functions
as a function of crystal thickness. The calculation uses Bloch-waves and it is controlled in a identical way.
The Channeling pane is shown in Fig. 1. The sliders to adjust the camera length and
deviation are activated by 
tool button.
The Imaging tabbed pane allows to duplicate nx × ny the images.
The sliders of the Image stack pane control the thickness of the crystal (Fig. 2a), the Options pane allows to select the Atomic Form Factors and to save the image stack either as formatted images or raw images, i.e. floating point (Fig. 2b).
The Reflections pane controls the number of reflections included in the stack calculation (Fig. 2c).
The calculation is started using the Start tool button. The calculation time depends on the number of reflections and the number of steps. When finished a stack of images is displayed (Figures 3a, 3b) and the wave-function after each step is displayed in the Wave-functions pane (Fig. 4).
The image stack box contains tool buttons to:
Print the window.
Save the window.
Tranfer the whole window to the clipboard.
Reset gray scale.
Tabulate the displayed image.
Suppress noise (if any).
Show this help file.
The first checkbox colorizes the stack and the second sets a unique intensity scale for each image of the stack (Color lut and Group contrast). The radio buttons x-y, x-z, y-z control the view direction.
The two sliders select the image of the stack to display and modify the image contrast.
The wave-function stack display is controlled by the sliders of the toolbox. Two tool buttons allow to:
- Tabulate the displayed wave-function.
Create a stack of wave-functions.
The stack of wave-functions is shown in Figures 5a, 5b. The intensity at the atomic columns position show the typical increase-decrease as a function of crystal thickness.
