CALM is a stand-alone software for determining the lattice parameters of the best-fitting Bravais lattice types and thus the very likely crystal symmetry of a typically unknown phase from a single large-angle EBSD1 or TKD2 pattern.
The animation shows the result from a single pattern which represents an incomplete arrangement of reciprocal lattice points. This is used to identify the Bravais lattice type and decides about the lattice parameters.
For the selected lattice type, the darker dots represent centerings whereas the bright dots indicate unit cell corners. The omnipresent translation symmetry leads to the fact that not all points of the represented unit cell are or have to be occupied.
CALM allows a playful recognition of fundamental relationships between crystal and reciprocal lattice and thus offers interesting options for university education and teaching.
Please note: Lattice parameter determination with CALM only makes sense if much more accurate methods like XRD3 fail, or alternative methods like local phase characterisation in TEM4 are not available, more time consuming and possibly also more complicated.
Operation
The software has a graphical user interface with check boxes and radio buttons and is operated by mouse and keyboard shortcuts. For ergonomic reasons, however, a typical menu- or button bar-driven operating concept is deliberately avoided.
1 electron backscatter diffraction
2 transmission Kikuchi diffraction
3 X-ray diffraction
4 transmission electron microscopy