source: trunk/tutorial1/nickel3.html @ 206

Last change on this file since 206 was 206, checked in by toby, 13 years ago

# on 2000/06/09 03:57:42, toby did:
incorporate many useful comments by Egbert Keller

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  • Property rcs:date set to 2000/06/09 03:57:42
  • Property rcs:lines set to +4 -1
  • Property rcs:rev set to 1.3
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  • Property svn:keywords set to Author Date Revision Id
File size: 4.1 KB
3   <META NAME="Author" CONTENT="Brian H. Toby">
4   <title>EXPGUI Tutorial #3</title>
8<A HREF=>
9<IMG SRC="" 
10alt="Link to NIST Center for Neutron Research home page"
12<A HREF=>
13<IMG SRC="" 
14alt="Link to National Institute of Standards & Technology home page"
17<A Href="">
18<IMG SRC="tcltklogo100.gif" 
19alt="Link to Tcl/Tk information">
24<H1>GSAS Nickel example using EXPGUI (part 3)</H1>
273. Add data (histograms) to the Experiment
30The next step in the tutorial is to add data. Note that
31GSAS uses the term
32histogram to refer to a powder diffraction data set.
33To 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>
36This brings up the "add new histogram" dialog, to the left.
37Press on the upper "Select File" button for a dialog box to select
38a data file.
40<BR clear=left>
41<img src="addhs2.gif" ALIGN=LEFT>
42Select the appropriate file, in this case nickel.raw and press
43the "Open" button.
45At this stage, different things can happen.
46If the file is not correctly formatted,
47<A HREF="nickelnotes.html#reformat">a dialog will offer
48to convert the file to the correct format.</a>
49Also, in some cases, the data file specifies the name of the instrument
50parameter file. If so, that name will be loaded into the "Instrument
51Parameter file" box. If not, as in this case, the file must be selected
52by pressing the lower "Select File" button which creates a
53dialog box to select an instrument parameter file, similar
54to the one above.
56<BR clear=left>
57<img src="addhs3.gif" ALIGN=LEFT>
58After the appropriate instrument parameter file is located and selected,
59one must select the bank of data (if more than one) and the bank of the
60instrument parameters (if more than one) using the bank checkbuttons.
61Finally one must enter either the minimum d-space or
62maximum time-of-flight or two-theta to be used from the data (note that
63this value can be changed later if need be from EXPEDT). A
64good way to do this is to use
65<A HREF="nickelnotes.html#rawplot">RAWPLOT</A>
66to look at the data. This is done
67by pressing the "Run RAWPLOT" button at the
68lower right <A HREF="nickelnotes.html#rawplot">(example).</A>
69This invokes the GSAS RAWPLOT program. Note that you will need to specify the
70same data and instrument parameters file names to RAWPLOT to see a
71plot of the data.
74When all input is complete, press Add to run program EXPTOOL and read the
75data into the .EXP file.
77<BR clear=left>
78<img src="addhs4.gif" ALIGN=LEFT>
79The results from the EXPTOOL are shown in a separate box, so
80that errors can be noted.
82<BR clear=left>
83<img src="addhs5.gif" ALIGN=LEFT>
84The above procedure is then repeated for the third bank of data, but this
85time the maximum time-of-flight is changed to 1.5.
86<P>After Add is pressed, the EXPTOOL results are
87displayed and then the histogram panel is
88updated so that the diffraction parameters
89for each of the two histograms can be examined
90(see below).
91<BR clear=left>
92<img src="addhs6.gif">
93<BR clear=left>
94There is one deviation in the above
95compared to the tutorial in the GSAS manual.
96In that tutorial the
97data compression factor is set to 2 for the
98first histogram, averaging pairs
99of points to speed up
100the computations. This cannot be done from EXPGUI.
101If desired, it can be done using EXPEDT, but for
102most modern computers this tutorial will still run
103in seconds with no compression.
105<P><BR>(.EXP Snapshot:
106<A HREF="">
110<BR clear=left><HR>
111Previous step: <A HREF="nickel2.html">
112Add a phase to the Experiment</A>
114Next step: <A HREF="nickel4.html">
115 Change a profile parameter</A>
117<BR clear=left>
118<HR><p><a href="">Brian Toby</a> (<a href="">Brian.Toby@NIST.GOV</a>)
119<BR clear=left>
120$Revision: 206 $ $Date: 2009-12-04 23:02:10 +0000 (Fri, 04 Dec 2009) $
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