Tutorial(First Steps): Difference between revisions

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=== Getting [[XDS.INP]] ===
=== Getting [[XDS.INP]] ===
You must know the type of detector your data were collected on. Then visit the [http://www.mpimf-heidelberg.mpg.de/~kabsch/xds/html_doc/xds_prepare.html XDS Homepage], download the appropriate template and rename it to [[XDS.INP]].
You must know the type of detector your data were collected on. Then visit the [http://xds.mpimf-heidelberg.mpg.de/html_doc/xds_prepare.html XDS Homepage], download the appropriate template and rename it to [[XDS.INP]].


== Editing [[XDS.INP]] ==
== Editing [[XDS.INP]] ==
This tutorial uses the template for XDS-MARCCD.INP (templates can be downloaded from [http://www.mpimf-heidelberg.mpg.de/~kabsch/xds/html_doc/xds_prepare.html].
This tutorial uses the template for XDS-MARCCD.INP (templates can be downloaded from [http://xds.mpimf-heidelberg.mpg.de/html_doc/xds_prepare.html].


Open [[XDS.INP]] with your favourite text editor (e.g. gedit, kate, kwrite, vim, emacs...) and make the following adjustments (from top to bottom):  
Open [[XDS.INP]] with your favourite text editor (e.g. gedit, kate, kwrite, vim, emacs...) and make the following adjustments (from top to bottom):  


# '''Pixel Size'''  Find out the number of pixels of your detector. A very good program to find aus is [http://www.scripps.edu/~arvai/adxv.html adxv]: It allows to view the image header where these numbers often can be found. [[Image:Adxv_menu.jpeg|100px|adxv image viewer, main menu]] [[Image:Adxv_pixelsize.jpeg|100px|adxv showing image header info. Pixel size is highlighted]]
* '''Pixel Size'''  Find out the number of pixels of your detector. A very good program to find this is [http://www.scripps.edu/~arvai/adxv.html adxv] (also see the wiki article [[adxv]]): It allows to view the '''image header''' where these numbers often can be found. [[Image:Adxv_menu.jpeg|200px|adxv image viewer, main menu]] [[Image:Adxv_pixelsize.jpeg|300px|adxv showing image header info. Pixel size is highlighted]]
# '''Adjusting JOB Card''' Make a copy of the '''JOB''' line in [[XDS.INP]] for reference. Comment out one line by putting a exclamation mark "!" at the beginning of the line and prepare the other one to run the steps from XYCORR to CORRECT.[[Image:XDS_INP_adjustingJOB.jpeg|200px|Adjusting the JOB card in XDS.INP]]
* '''Adjusting JOB Card''' Make a copy of the '''JOB''' line in [[XDS.INP]] for reference. Comment out one line by putting a exclamation mark "!" at the beginning of the line and prepare the other one to run the steps from XYCORR to CORRECT.[[Image:XDS_INP_adjustingJOB.jpeg|400px|Adjusting the JOB card in XDS.INP]]
# '''ORGX and ORGY''' Unless you can guess the direct beam position on the images, ''e.g.'' from ice rings, set both these values to half the detector size. In the case of this example, where the MAR-CCD is 3072x3072 pixels, this means
* '''ORGX and ORGY''' Unless you can guess the direct beam position on the images, ''e.g.'' from ice rings, set both these values to half the detector size. In the case of this example, where the MAR-CCD is 3072x3072 pixels, this means
   ORGX=1536.00 ORGY=1536.00  !Detector origin (pixels).
   ORGX=1536.00 ORGY=1536.00  !Detector origin (pixels).
#'''Experiment specific settings''' The following numbers are also usually found in the image header:
* '''Experiment specific settings''' The following numbers are also usually found in the image header (or in your lab notebook, or in logs written by the beamline software):
  DETECTOR_DISTANCE= 150.0  !(mm)
  DETECTOR_DISTANCE= 150.0  !(mm)
  OSCILLATION_RANGE=1.0            !degrees (>0)
  OSCILLATION_RANGE=1.0            !degrees (>0)
  X-RAY_WAVELENGTH=1.07176        !Angstroem
  X-RAY_WAVELENGTH=1.07176        !Angstroem
  NAME_TEMPLATE_OF_DATA_FRAMES=./images/tutorial_????.img  ! TIFF
  NAME_TEMPLATE_OF_DATA_FRAMES=./images/tutorial_????.img  ! TIFF
  DATA_RANGE=1 180    !Numbers of first and last data image collected
  DATA_RANGE=1 180    !Numbers of first and last data image collected
#'''Background range''' The default template suggests to use the first 5 images for detecting the average background per image. It does not harm to increase this number to 20 images. Especially with frame width of less than 1 degree you should do this.
  SPOT_RANGE=1  90    !images to be used for indexing; 1 180 would be better unless there is radiation damage
  BACKGROUND_RANGE=1 20 !Numbers of first and last data image for background
 
Then data processing can 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 ==
== Indexing Fails ==
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  !!! ERROR !!! SOLUTION IS INACCURATE
  !!! ERROR !!! SOLUTION IS INACCURATE
Do the following:
Do the following:
# In IDXREF.LP, find the table '''INDEXING OF OBSERVED SPOTS IN SPACE GROUP'''
* In IDXREF.LP, find the table '''INDEXING OF OBSERVED SPOTS IN SPACE GROUP'''
  ***** INDEXING OF OBSERVED SPOTS IN SPACE GROUP #  1 *****
  ***** INDEXING OF OBSERVED SPOTS IN SPACE GROUP #  1 *****
   16196 OUT OF  76452 SPOTS INDEXED.
   16196 OUT OF  76452 SPOTS INDEXED.
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  DETECTOR ORIGIN (PIXELS) AT                    1514.16  1537.27
  DETECTOR ORIGIN (PIXELS) AT                    1514.16  1537.27
as improved ORGX and ORGY to [[XDS.INP]] and try indexing again.
as improved ORGX and ORGY to [[XDS.INP]] and try indexing again.
XDS is quite robust and in many cases this approach works
XDS is quite robust and in many cases this approach works. If not, read [[Obtaining ORGX ORGY]].
# Check the refined detector distance
* Check the refined detector distance
  DETECTOR ORIGIN (PIXELS) AT                    1514.16  1537.27
  DETECTOR ORIGIN (PIXELS) AT                    1514.16  1537.27
  CRYSTAL TO DETECTOR DISTANCE (mm)      422.92     
  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
If it deviates by more than 1-2mm from the input distance, check all your 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
  SPOT_RANGE = 1 20
== See also ==
[https://{{SERVERNAME}}/pub/MWhitley_CSHL-2018_XDS-Tutorial.pdf Matthew J. Whitley's excellent tutorial] about XDS processing with [[XDSGUI]], from the 2018 Cold Spring Harbor X-Ray Methods in Structural Biology Course.
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