Changes between Version 7 and Version 8 of DemoCalibrateTilted

Sep 6, 2012 4:12:21 PM (10 years ago)



  • DemoCalibrateTilted

    v7 v8  
    55=== Step 1: download the data file  ===
    66Download the sample data file from one of these links:
    8     or
     8    or
    1010=== Step 2: Start GSAS-II ===
    3131 Use the '''Data/Read image data''' menu item to read the data file into the current GSAS-II project.
    32  ([ view]).
     32 ([ view]).
    3333 Select the {{{La_hex_+45deg-00015.tif}}} data file and press Open.
    3535 At this point the data tree window will have several entries
    36  ([ view]); the plot window
     36 ([ view]); the plot window
    3737 shows a faint image
    38  ([ view]) and a new window
     38 ([ view]) and a new window
    3939 is opened to edit the image controls
    40  ([ view]). 
     40 ([ view]). 
    4242=== Step 4: Edit image parameters ===
    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.
    57    ([ view]).
     57   ([ view]).
    5959 Third:
    6060  Use the left mouse button to click on at least five locations on the innermost ring. As each point is defined, a red "+" is added to the plot
    61   ([ view]). 
     61  ([ view]). 
    6363  To remove a point added in error click on that point with the right mouse button [on the Mac, if you have a single-button mouse, hold the Command (⌘) key down and click].
    6666  When done, press the right mouse button well away from any points that have been added [on the Mac, if you have a single-button mouse, hold the Command (⌘) key down and click].
    6767 The calibration is then performed. First the rings are located and an ellipse is optimized for each ring. The indexed rings are first shown in red as the calibration proceeds and center of each ellipse is noted with a blue "+". When all rings have been fitted, the entire ensemble of rings are refitted to the detector parameters and the rings are then shown in blue.
    68  ([ view]).
     68 ([ view]).
    6969 The derived calibration results are shown in the Image Controls window.
    70  ([ view]).
     70 ([ view]).
    7171 and the console window shows details of the fit; a trial refinement for the wavelength is also given for you to consider.
    7272 To see the actual points selected by the program, click on the "show ring picks?" check button
    73  ([ view]).
     73 ([ view]).
    7474 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 changing the "pixel search range" to 10 and then repeating the last calibration step (using the right mouse button)
    75  ([ view]).
     75 ([ view]).
    7676 This produces very slightly better calibration constants
    77  ([ view]).
     77 ([ view]).
    7979 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.