The STAC software can be started by typing the command "stac" in a Unix terminal. Quite often it doesn't start smoothly at the first attempt. Killing the process with CTRL-C and then restarting STAC is the recommended procedure. Once the software is started it comes up with a main window and a small job control window. The main window is organised in different tabs:
Motor Access: Allows to control the rotations omega, kappa, phi and the sample centring stages gonx, samy, samz plus an option to tilt the crystal
Input for Re-orientation: This is where calculation tasks are defined
Vector Evaluation: This tab shows the results of orientation calculations
Strategy: If a strategy at a certain orientation is requested the results will be shown here
STAC provides the following calculation options:
Sometimes an exact orientation cannot be calculated. In this case the user can tick the "Close" tickbox. STAC will then try to calculate a solution that is close to the requested input,
e.g. (0.95, 0, 0) instead of (1, 0, 0).
Examples of input options are given below
Calculation results are presented in the "Vector Evaluation" tab. Sometimes there is a pop-up window indicating the cases for which no solution could be found. The results are presented in a table.
An example screenshot is given below
STAC can calculate data collection strategies based on a chosen orientation solution. These are purely geometric, biased towards completeness, and don't take into account any other sample information. Use of this option is therefore discouraged.
Work is in progress to provide better strategies when using the mini kappa. An automatic workflow is also under development.
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