→How it works
== Overview ==
This plugin can be used to quickly calculate the interplanar spacing values ''(d)'' directly within imageJ without copying the results table to another program like Excel to then convert measurements into d-values, which saves you time. It is also remarkably easy to use, accurate, and robust for both spot and ring electron diffraction patterns.
== How it works ==
Use imageJ’s circle tool (shift + oval tool) to measure the spot/ring patterns concentric to the (000) direct beam. From the area measurement, the radius (G) is found. From G = 1/d in reciprocal space, the d-spacing is calculated for each measurement made.
The calculated values for G and d are added to the imageJ Results window in new columns.
You need to have a properly calibrated diffraction pattern for the calculations to work. Most
TEM operators use Gatan’s Digital Micrograph software for image collection. If you are using DM, then it is likely that this plugin will work right away, or will work with the help of your TEM technician.
The preferred image is a .dm3 file (Gatan’s format) that is properly calibrated in reciprocal space (see Gatan’s documentation). The easiest way to check this is that the scale bar in your images is displayed in DM with 1/nm units.
== Example ==
The example below is from a single crystalline STO (strontium titanate) sample. It illustrates how the measurements should be made in order to ensure the plugin is calculating the d-spacing values accurately. Make your measurements working from the inner most spots/rings outwards.
There are 3 new columns in the Results window: G, d, 2% error. The scalar component of the G vector in reciprocal space is found and measured in 1/nm since these are the image units. The d-spacing is listed in Angstroms, and the 2% error is just 2% of the d-spacing. While it is ''not'' an actual uncertainty measurement, it can help you index your sample.
== Tips ==
# If you hold down both control and shift while clicking on one of the white squares on the circle and dragging, the circle expands and contracts concentrically.