| [159] | 1 | <html> |
|---|
| 2 | <head> |
|---|
| 3 | <META NAME="Author" CONTENT="Brian H. Toby"> |
|---|
| 4 | <title>EXPGUI Tutorial #3</title> |
|---|
| 5 | </head> |
|---|
| 6 | <BODY BGCOLOR="#FFFFFF"> |
|---|
| 7 | |
|---|
| 8 | <A HREF=http://www.ncnr.nist.gov> |
|---|
| 9 | <IMG SRC="http://www.ncnr.nist.gov/images/ncnrtrans.gif" |
|---|
| 10 | alt="Link to NIST Center for Neutron Research home page" |
|---|
| 11 | ALIGN=RIGHT></A> |
|---|
| 12 | <A HREF=http://www.nist.gov> |
|---|
| 13 | <IMG SRC="http://www.ncnr.nist.gov/images/webidblue_2lineright.gif" |
|---|
| 14 | alt="Link to National Institute of Standards & Technology home page" |
|---|
| 15 | ALIGN=LEFT></A> |
|---|
| 16 | <CENTER> |
|---|
| 17 | <A Href="http://www.ncnr.nist.gov/programs/crystallography/software/tclpkgs.html"> |
|---|
| 18 | <IMG SRC="tcltklogo100.gif" |
|---|
| 19 | alt="Link to Tcl/Tk information"> |
|---|
| 20 | </CENTER></A> |
|---|
| 21 | <hr> |
|---|
| 22 | |
|---|
| 23 | <CENTER> |
|---|
| 24 | <H1>GSAS Nickel example using EXPGUI (part 3)</H1> |
|---|
| 25 | </CENTER> |
|---|
| 26 | <H1> |
|---|
| 27 | 3. Add data (histograms) to the Experiment |
|---|
| 28 | </H1> |
|---|
| 29 | |
|---|
| 30 | The next step in the tutorial is to add data. Note that |
|---|
| 31 | GSAS uses the term |
|---|
| 32 | histogram to refer to a powder diffraction data set. |
|---|
| 33 | To add data, switch to the Histogram in EXPGUI pane and press the |
|---|
| 34 | "Add New Histogram" button in the lower right. |
|---|
| 35 | <img src="addhs1.gif" ALIGN=LEFT> |
|---|
| 36 | This brings up the "add new histogram" dialog, to the left. |
|---|
| 37 | Press on the upper "Select File" button for a dialog box to select |
|---|
| 38 | a data file. |
|---|
| 39 | |
|---|
| 40 | <BR clear=left> |
|---|
| 41 | <img src="addhs2.gif" ALIGN=LEFT> |
|---|
| 42 | Select the appropriate file, in this case nickel.raw and press |
|---|
| 43 | the "Open" button. |
|---|
| 44 | |
|---|
| 45 | At this stage, different things can happen. |
|---|
| 46 | If the file is not correctly formatted, |
|---|
| 47 | <A HREF="nickelnotes.html#reformat">a dialog will offer |
|---|
| 48 | to convert the file to the correct format.</a> |
|---|
| 49 | Also, in some cases, the data file specifies the name of the instrument |
|---|
| 50 | parameter file. If so, that name will be loaded into the "Instrument |
|---|
| 51 | Parameter file" box. If not, as in this case, the file must be selected |
|---|
| 52 | by pressing the lower "Select File" button which creates a |
|---|
| 53 | dialog box to select an instrument parameter file, similar |
|---|
| 54 | to the one above. |
|---|
| 55 | |
|---|
| 56 | <BR clear=left> |
|---|
| 57 | <img src="addhs3.gif" ALIGN=LEFT> |
|---|
| 58 | After the appropriate instrument parameter file is located and selected, |
|---|
| 59 | one must select the bank of data (if more than one) and the bank of the |
|---|
| 60 | instrument parameters (if more than one) using the bank checkbuttons. |
|---|
| 61 | Finally one must enter either the minimum d-space or |
|---|
| 62 | maximum time-of-flight or two-theta to be used from the data (note that |
|---|
| 63 | this value can be changed later if need be from EXPEDT). A |
|---|
| [185] | 64 | good way to do this is to use |
|---|
| [159] | 65 | <A HREF="nickelnotes.html#rawplot">RAWPLOT</A> |
|---|
| 66 | to look at the data. This is done |
|---|
| 67 | by pressing the "Run RAWPLOT" button at the |
|---|
| 68 | lower right <A HREF="nickelnotes.html#rawplot">(example).</A> |
|---|
| 69 | |
|---|
| 70 | |
|---|
| 71 | When all input is complete, press Add to run program EXPTOOL and read the |
|---|
| 72 | data into the .EXP file. |
|---|
| 73 | |
|---|
| 74 | <BR clear=left> |
|---|
| 75 | <img src="addhs4.gif" ALIGN=LEFT> |
|---|
| 76 | The results from the EXPTOOL are shown in a separate box, so |
|---|
| 77 | that errors can be noted. |
|---|
| 78 | |
|---|
| 79 | <BR clear=left> |
|---|
| 80 | <img src="addhs5.gif" ALIGN=LEFT> |
|---|
| 81 | The above procedure is then repeated for the third bank of data, but this |
|---|
| 82 | time the maximum time-of-flight is changed to 1.5. |
|---|
| 83 | <P>After Add is pressed, the EXPTOOL results are |
|---|
| 84 | displayed and then the histogram panel is |
|---|
| 85 | updated so that the diffraction parameters |
|---|
| 86 | for each of the two histograms can be examined |
|---|
| 87 | (see below). |
|---|
| 88 | <BR clear=left> |
|---|
| 89 | <img src="addhs6.gif"> |
|---|
| 90 | <BR clear=left> |
|---|
| 91 | There is one deviation in the above |
|---|
| 92 | compared to the tutorial in the GSAS manual. |
|---|
| 93 | In that tutorial the |
|---|
| 94 | data compression factor is set to 2 for the |
|---|
| 95 | first histogram, averaging pairs |
|---|
| 96 | of points to speed up |
|---|
| 97 | the computations. This cannot be done from EXPGUI. |
|---|
| 98 | If desired, it can be done using EXPEDT, but for |
|---|
| 99 | most modern computers this tutorial will still run |
|---|
| 100 | in seconds with no compression. |
|---|
| 101 | |
|---|
| 102 | <P><BR>(.EXP Snapshot: |
|---|
| 103 | <A HREF="ftp://ftp.ncnr.nist.gov/pub/cryst/gsas/tutorials/nickel3.exp"> |
|---|
| 104 | nickel3.exp |
|---|
| 105 | </A>) |
|---|
| 106 | |
|---|
| 107 | <BR clear=left><HR> |
|---|
| 108 | Previous step: <A HREF="nickel2.html"> |
|---|
| 109 | Add a phase to the Experiment</A> |
|---|
| 110 | <BR> |
|---|
| 111 | Next step: <A HREF="nickel4.html"> |
|---|
| 112 | Change a profile parameter</A> |
|---|
| 113 | |
|---|
| 114 | <BR clear=left> |
|---|
| 115 | <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>) |
|---|
| 116 | <BR clear=left> |
|---|
| 117 | $Revision: 185 $ $Date: 2009-12-04 23:01:49 +0000 (Fri, 04 Dec 2009) $ |
|---|
| 118 | </body> |
|---|
| 119 | </html> |
|---|
