Large Angle Convergent Beam patterns without CBED disks overlap are calculated when the LACBED check box is selected. Combined with a dark field condition (i.e. optical axis set to the (h,k,l) disk or LACBED selector at (h,k,l) disk) and the shift, the dark field disk can be shifted to the middle of the CBED pattern. When the LACBED selector is set at a (h,k,l) disk and the optical axis in not set to the same (h,k,l) disk the pattern is shifted in order to set the optical axis at the center. The size of the LACBED selector aperture (SAED aperture) is irrelevant. The ZOLZ option shows the position of ZOLZ deficiency lines. The Area option only calculates the CBED pattern in a rectangular area. LACBED patterns with beam half convergence up to 100 mrad can be calculated. The next figure shows a LACBED pattern form Si [0,3,-4] at 300 kV and convergence 13.44 mrad. The specimen thickness and the contrast are changed by sliders activated by the tool button.
The tool button superpose the kinematically calculated HOLZ lines on the dynamically calculated LACBED (with 55 reflections, 228'965 iterations, 12 seconds Apple Macbook Pro M1).
