ar345 Program Manual 2 2
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.14 X−ray Setup
When producing images during data collection many parameters concerning the curren
experiment are automatically written into the output image headers, so this information ca
be retrieved later on. This is most relevant for parameters like the distance and th
goniometer positions. It might, however, be useful to add also some information about th
state of the X−ray source. Unfortunately, the program mar345 does not have knowledg
about the generator and collimator settings, so this information must be entered manuall
For this purpose, open the mar345−X−ray Setup window. This window can be popped u
manually from the main window menubar or by pressing the F3 key. All information give
here is really not essential but it may help later on to track down problems during dat
processing.
The center of diffraction is supposed to be a physical constant (for one data set) and is val
for all scan modes, regardless if working at 0.15 or 0.10 mm pixelsize. This is why the cente
should not be entered in absolute pixels or millimeters referring to an origin in the lower le
corner but as a deviation from the center of the image plate. These values should be given
mm, not in pixels, and can become negative. Negative x deviation means that the center o
diffraction is left of the IP−center. A negative y deviation would be underneath the IP−center
