Get dSpace

Revision as of 20:32, 14 May 2018 by Makoten (talk | contribs) (Getting Started)

This plugin provides a more impartial and mathematically sound way of calculating interplanar spacing, which makes it more accurate than calc dSpace. It is also easier to use on diffraction patterns where it is hard to tell which reflections originate at like planes in the crystal. Get dSpace helps the user figure this out.

How it Works

A threshold is applied to the diffraction pattern that the user can manipulate so it suites their image. The centroid of the thresholded region is then found, and the d-spacing value is calculated for each spot as the inverse of the distance from the center spot. If you did not use a beamstop for image capture, the direct beam spot corresponds to one of the spots in the image, and the user tells the plugin which spot to use. If a beamstop was used for image capture, then the user picks a pair of spots symmetric about the direct beam spot and the plugin finds the center from those two positions. It then bins the measurements according to their difference and plots the values for the user to see and confirm that it is binning like reflections and coming up with an accurate value for that plane.


Getting Started

This is the window that opens up when you first start the plugin. All you need for the plugin to work is an opened diffraction pattern that is calibrated and saved as a .dm3 file.

First Window1.jpg
  • Minimum diffraction spot size: is on less pixel than the number of pixels you choose as constituting a diffraction spot. It is good for ignoring cosmic rays that might be captured in you SADP, and small fringe spots that sometimes show up near diffraction spots.
  • Beamstop Status: choose the appropriate option regarding whether or not a beamstop was used to block the direct beam.
  • Display modes: these options allow the user to operate the plugin in three different modes. The Measurements mode does not give you a summary plot or table, which is convenient if you are optimizing your settings for a single SADP. The Summary mode closes the two measurement windows (so you don't have to) and only shows the summary table and plot. All leaves all four windows open, so you see everything.
  • d-spacing list: yet a fifth window that you can enable, which allows you to view the list of d-spacing values in a text window on a single line.

Adjust Threshold

Adjust Threshold 1.jpg

Direct Beam Spot

Direct Beam Center 1.jpg


Measurements 1.jpg

Results Windows

Results Windows 1.jpg