Changes between Version 1 and Version 2 of DemoCalibrateTilted


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Timestamp:
Jul 30, 2011 5:48:46 PM (11 years ago)
Author:
toby
Comment:

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  • DemoCalibrateTilted

    v1 v2  
    11= Calibration of an area detector in GSAS-II =
    22
    3 ''In this demo, data collected with a GE(?) area detector, intentionally tilted at 45 degrees, are used. Note that menu entries are listed below as Help/About GSAS-II, which lists first the name of the menu (here "Help") and second the name of the entry in the menu (here "About GSAS-II").''
     3''In this demo, data collected with a GE(?) area detector, intentionally tilted at 45 degrees, are used. Note that menu entries are listed below as'' '''Help/About GSAS-II''''', which lists first the name of the menu (here "Help") and second the name of the entry in the menu (here "About GSAS-II").''
    44
    55=== Step 1: download the data file  ===
     
    2929=== Step 3: read in the data file ===
    3030
    31  Use the Data/Read image data menu item to read the data file into the current GSAS-II project.
     31 Use the '''Data/Read image data''' menu item to read the data file into the current GSAS-II project.
    3232 ([https://subversion.xor.aps.anl.gov/trac/pyGSAS/attachment/wiki/DemoIntegrateTilted/d1m1.png view]).
    3333 Select the La_hex_+45deg-00015.tif data file and press Open.
     
    4242=== Step 4: Edit image parameters ===
    4343
    44  Note that, alas, very few image formats allow for storage of important metadata about the image, so this information needs to be added manually. In this case set the '''wavelength to 0.10798'''. It is also helpful to change the display of the image so that it is easier to see the diffraction rings. Lowering the maximum intensity to 10,000 to 20,000 counts will help (note that this can be done by moving the slider, or by typing a value in the box and then clicking on another control). You may also wish to select another color scheme using the color bar selector.
     44 Note that, alas, very few image formats allow for storage of important metadata about the image, so this information needs to be added manually. In this case set the '''''wavelength to 0.10798'''''. It is also helpful to change the display of the image so that it is easier to see the diffraction rings. Lowering the maximum intensity to 10,000 to 20,000 counts will help (note that this can be done by moving the slider, or by typing a value in the box and then clicking on another control). You may also wish to select another color scheme using the color bar selector.
    4545
    4646 Alternately, the view of the image can be enhanced by displaying it on a logarithmic scale. Click on the window and press the upper or lowercase "L" key to toggle logarithmic plotting, or use the keypress selector button at the lower left of this window.
     
    5252
    5353 Second:
    54    Use the Image Operations/Calibrate menu item (note this menu is on the Image Controls window or for the Mac, the Image
     54   Use the '''Image Operations/Calibrate''' menu item (note this menu is on the Image Controls window or for the Mac, the Image
    5555   Controls window must be active to place this into the system menu bar). At this point the status line on the bottom of the
    5656   Image Controls window changes with a prompt to select points for calibration.
     
    7373 To see the actual points selected by the program, click on the "show ring picks?" check button
    7474 ([https://subversion.xor.aps.anl.gov/trac/pyGSAS/attachment/wiki/DemoIntegrateTilted/d1w8.jpg view]).
    75  When this is done, it becomes clear that the points selected for the outermost ring are scattered between that and the next ring. This can be repaired by using the Image Operations/Clear Calibration menu item, lowering the area the program uses for searching for points by changing the "pixel search range" to 10 and then repeating the calibration steps (selecting points again on the first ring and then using the right mouse button)
     75 When this is done, it becomes clear that the points selected for the outermost ring are scattered between that and the next ring. This can be repaired by using the '''Image Operations/Clear Calibration''' menu item, lowering the area the program uses for searching for points by changing the "pixel search range" to 10 and then repeating the calibration steps (selecting points again on the first ring and then using the right mouse button)
    7676 ([https://subversion.xor.aps.anl.gov/trac/pyGSAS/attachment/wiki/DemoIntegrateTilted/d1w10.jpg view]).
    7777 This produces very slightly better calibration constants
    7878 ([https://subversion.xor.aps.anl.gov/trac/pyGSAS/attachment/wiki/DemoIntegrateTilted/d1w9.jpg view]).
    7979
    80  Assuming that these calibration results will be applied to other images in the same GSAS-II project, click on "Use as default for all images." To save the project, including the now-derived calibration information, use the File/Save Project menu item associated with the data tree window.
     80 Assuming that these calibration results will be applied to other images in the same GSAS-II project, click on "Use as default for all images." To save the project, including the now-derived calibration information, use the '''File/Save Project''' menu item associated with the data tree window.
    8181
    8282== Next step: [DemoIntegrateTilted Integrate the Data] ==