Tutorial(First Steps): Difference between revisions

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New page: = A beginner's walk-through to XDS = ''This page is under development. If you think it might be useful to you and worth completing faster, why not simply bother the author by sending him ...
 
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This is it to start. type <pre>#> xds_par </pre> to run xds and wait until it's finished.
This is it to start. type <pre>#> xds_par </pre> to run xds and wait until it's finished.
== Indexing Fails ==
If the detector origin is too far from the image centre, IDXREF is going to stop with the error message
!!! ERROR !!! SOLUTION IS INACCURATE
Do the following:
<source lang=fortran>
# In IDXREF.LP, find the table '''INDEXING OF OBSERVED SPOTS IN SPACE GROUP'''
***** INDEXING OF OBSERVED SPOTS IN SPACE GROUP #  1 *****
  16196 OUT OF  76452 SPOTS INDEXED.
      0 REJECTED REFLECTIONS (REASON: OVERLAP)
  60256 REJECTED REFLECTIONS (REASON: TOO FAR FROM IDEAL POSITION)
EXPECTED ERROR IN SPINDLE  POSITION    2.398 DEGREES
EXPECTED ERROR IN DETECTOR POSITION      1.72 PIXELS
</source>
Unless really hardly any reflections could be indexed (second line in the table), scroll a few lines up and copy the refined values for the beam origin
DETECTOR ORIGIN (PIXELS) AT                    1514.16  1537.27
as improved ORGX and ORGY to [[XDS.INP]] and try indexing again.
XDS is quite robust and in many cases this approach works
# Check the refined detector distance
DETECTOR ORIGIN (PIXELS) AT                    1514.16  1537.27
CRYSTAL TO DETECTOR DISTANCE (mm)      422.92   
If it deviates by more than 1-2mm from the input distance, check all you parameters again. Is the wavelength really correct, as well as the distance? If you are sure about them, try indexing with only a few images
SPOT_RANGE = 1 20