| 1 | <html> |
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| 2 | <head> |
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| 3 | <META NAME="Author" CONTENT="Brian H. Toby"> |
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| 4 | <title>EXPGUI Tutorial #3</title> |
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| 5 | </head> |
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| 6 | <BODY BGCOLOR="#FFFFFF"> |
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| 7 | |
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| 8 | <A HREF=http://www.ncnr.nist.gov> |
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| 9 | <IMG SRC="http://www.ncnr.nist.gov/images/ncnrtrans.gif" |
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| 10 | alt="Link to NIST Center for Neutron Research home page" |
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| 11 | ALIGN=RIGHT></A> |
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| 12 | <A HREF=http://www.nist.gov> |
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| 13 | <IMG SRC="http://www.ncnr.nist.gov/images/webidblue_2lineright.gif" |
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| 14 | alt="Link to National Institute of Standards & Technology home page" |
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| 15 | ALIGN=LEFT></A> |
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| 16 | <CENTER> |
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| 17 | <A Href="http://www.ncnr.nist.gov/programs/crystallography/software/tclpkgs.html"> |
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| 18 | <IMG SRC="tcltklogo100.gif" |
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| 19 | alt="Link to Tcl/Tk information"> |
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| 20 | </CENTER></A> |
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| 21 | <hr> |
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| 22 | |
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| 23 | <CENTER> |
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| 24 | <H1>GSAS Nickel example using EXPGUI (part 3)</H1> |
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| 25 | </CENTER> |
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| 26 | <H1> |
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| 27 | 3. Add data (histograms) to the Experiment |
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| 28 | </H1> |
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| 29 | |
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| 30 | The next step in the tutorial is to add data. Note that |
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| 31 | GSAS uses the term |
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| 32 | histogram to refer to a powder diffraction data set. |
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| 33 | To add data, switch to the Histogram in EXPGUI pane and press the |
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| 34 | "Add New Histogram" button in the lower right. |
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| 35 | <img src="addhs1.gif" ALIGN=LEFT> |
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| 36 | This brings up the "add new histogram" dialog, to the left. |
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| 37 | Press on the upper "Select File" button for a dialog box to select |
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| 38 | a data file. |
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| 39 | |
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| 40 | <BR clear=left> |
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| 41 | <img src="addhs2.gif" ALIGN=LEFT> |
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| 42 | Select the appropriate file, in this case nickel.raw and press |
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| 43 | the "Open" button. |
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| 44 | |
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| 45 | At this stage, different things can happen. |
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| 46 | If the file is not correctly formatted, |
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| 47 | <A HREF="nickelnotes.html#reformat">a dialog will offer |
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| 48 | to convert the file to the correct format.</a> |
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| 49 | Also, in some cases, the data file specifies the name of the instrument |
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| 50 | parameter file. If so, that name will be loaded into the "Instrument |
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| 51 | Parameter file" box. If not, as in this case, the file must be selected |
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| 52 | by pressing the lower "Select File" button which creates a |
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| 53 | dialog box to select an instrument parameter file, similar |
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| 54 | to the one above. |
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| 55 | |
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| 56 | <BR clear=left> |
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| 57 | <img src="addhs3.gif" ALIGN=LEFT> |
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| 58 | After the appropriate instrument parameter file is located and selected, |
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| 59 | one must select the bank of data (if more than one) and the bank of the |
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| 60 | instrument parameters (if more than one) using the bank checkbuttons. |
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| 61 | Finally one must enter either the minimum d-space or |
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| 62 | maximum time-of-flight or two-theta to be used from the data (note that |
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| 63 | this value can be changed later if need be from EXPEDT). A |
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| 64 | good way to do this is to use |
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| 65 | <A HREF="nickelnotes.html#rawplot">RAWPLOT</A> |
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| 66 | to look at the data. This is done |
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| 67 | by pressing the "Run RAWPLOT" button at the |
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| 68 | lower right <A HREF="nickelnotes.html#rawplot">(example).</A> |
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| 69 | This invokes the GSAS RAWPLOT program. Note that you will need to specify the |
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| 70 | same data and instrument parameters file names to RAWPLOT to see a |
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| 71 | plot of the data. |
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| 72 | |
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| 73 | |
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| 74 | When all input is complete, press Add to run program EXPTOOL and read the |
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| 75 | data into the .EXP file. |
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| 76 | |
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| 77 | <BR clear=left> |
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| 78 | <img src="addhs4.gif" ALIGN=LEFT> |
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| 79 | The results from the EXPTOOL are shown in a separate box, so |
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| 80 | that errors can be noted. |
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| 81 | |
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| 82 | <BR clear=left> |
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| 83 | <img src="addhs5.gif" ALIGN=LEFT> |
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| 84 | The above procedure is then repeated for the third bank of data, but this |
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| 85 | time the maximum time-of-flight is changed to 1.5. |
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| 86 | <P>After Add is pressed, the EXPTOOL results are |
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| 87 | displayed and then the histogram panel is |
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| 88 | updated so that the diffraction parameters |
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| 89 | for each of the two histograms can be examined |
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| 90 | (see below). |
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| 91 | <BR clear=left> |
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| 92 | <img src="addhs6.gif"> |
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| 93 | <BR clear=left> |
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| 94 | There is one deviation in the above |
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| 95 | compared to the tutorial in the GSAS manual. |
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| 96 | In that tutorial the |
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| 97 | data compression factor is set to 2 for the |
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| 98 | first histogram, averaging pairs |
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| 99 | of points to speed up |
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| 100 | the computations. This cannot be done from EXPGUI. |
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| 101 | If desired, it can be done using EXPEDT, but for |
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| 102 | most modern computers this tutorial will still run |
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| 103 | in seconds with no compression. |
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| 104 | |
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| 105 | <P><BR>(.EXP Snapshot: |
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| 106 | <A HREF="ftp://ftp.ncnr.nist.gov/pub/cryst/gsas/tutorials/nickel3.exp"> |
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| 107 | nickel3.exp |
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| 108 | </A>) |
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| 109 | |
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| 110 | <BR clear=left><HR> |
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| 111 | Previous step: <A HREF="nickel2.html"> |
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| 112 | Add a phase to the Experiment</A> |
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| 113 | <BR> |
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| 114 | Next step: <A HREF="nickel4.html"> |
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| 115 | Change a profile parameter</A> |
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| 116 | |
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| 117 | <BR clear=left> |
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| 118 | <HR><p><a href="http://www.ncnr.nist.gov/staff/toby/">Brian Toby</a> (<a href="mailto:brian.toby@nist.gov">Brian.Toby@NIST.GOV</a>) |
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| 119 | <BR clear=left> |
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| 120 | $Revision: 206 $ $Date: 2009-12-04 23:02:10 +0000 (Fri, 04 Dec 2009) $ |
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| 121 | </body> |
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| 122 | </html> |
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