A new method for determination of the crystal setting matrix for interpreting oscillation photographs

The standard procedure for indexing oscillation photographs makes use of the partial reflections from two Laue photographs of a crystal taken with the incident beam parallel to any two principal axes of the crystal. A procedure is described using a graphics terminal of a microcomputer to display the calculated and observed diffraction patterns for an oscillation photograph and to examine visually all necessary rotations to get the best orientation matrix for the crystal. This method is particularly useful when the crystal is sensitive to X-rays and not easily amenable to setting photographs or Laue photographs.