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GSAS Nickel example using EXPGUI:


Below is an example of how to plot diffraction data in RAWPLOT. RAWPLOT is a good program for checking that data are appropriately formatted for GSAS. The screen input and output are shown in the box below. Computer output is formatted like this while user input is shown in bold. The generated plots are shown below the screen output.

                   |      Program RAWPLOT Version Linux6     |
                   |     Powder pattern plotting program     |
                   | Distributed on Sat Mar 25 18:15:44 2000 |

        |            Allen C. Larson and Robert B. Von Dreele           |
        |      Manuel Lujan, Jr. Neutron Scattering Center, MS-H805     |
        |      Los Alamos National Laboratory, Los Alamos, NM  87545    |
        |                                                               |
        | Copyright, 2000, The Regents of the University of California. |

 Enter graphic screen option (<?>,A,B,C) >B
 Do you want to save graphics output (Y,<N>)? >N
 Enter raw histogram input file name (<?>,$,QUIT)
 Header on file:
   NICKEL POWDER STANDARD, ROOM TEMP      22:32:50  9/ 8/1984
 Is this the correct file (<Y>/N/Q)? >y
 Enter POWDER instrument parameter file name (<?>,$,QUIT)
 The raw data file is : nickel.raw
 Enter bank number desired (<0 for list) >2
 Reading histogram - please wait
 Bank  2 DIFC =    4368.97 2-theta =     88.050
 Enter rawplot command (<?>,B,C,F,I,K,L,O,P,R,S,T,X) >
 RAWPLOT Commands:
  <?> - Type this help listing
  B   - Read new bank of data
  C   - Toggle cursor control
  F   - Read new raw data set
  I   - I/Io or I on Y-axis toggle
  K c - Enter compression ratio "c"
  L   - List plot options
  O   - Output text file of raw data
  P   - Plot histogram
  R   - Refine peak profiles
  S   - Set initial plot ranges toggle
  T   - D-spacing or TOF/2-theta/keV on X-axis toggle
  X   - Exit from RAWPLOT
 Enter rawplot command (<?>,B,C,F,I,K,L,O,P,R,S,T,X) >t p
 Plot will use TOF in msec
 Data compressed to  5119 channels by grouping  1 together
 Give X-min and X-max for next plot
  (default plot="0 0" & <CR> for no plot) >.5 2 a
 Give X-min and X-max for next plot
  (default plot="0 0" & <CR> for no plot) >
 Enter rawplot command (<?>,B,C,F,I,K,L,O,P,R,S,T,X) >x
STOP RAWPLOT terminated successfully statement executed
Press Enter to continue

After the "t" and "p" commands are typed (t for time-of-flight/two-theta and p to plot), the entire range of data are plotted.
Entering a range of TOF values, in this case 0.5 to 2.0 with automatic y-axis scaling (.5 2 a) displays this plot.

On-the-fly reformatting

GSAS has fairly strict formatting requirements. In UNIX experiment, raw data and instrument parameter files must be 80 characters to a line and may not have any line separators (no carriage return or line-feed characters). In Windows and DOS, these files must again be exactly 82 characters per line and each line must end with a carriage return and line-feed character. (These restrictions are being removed from newer versions of GSAS).

EXPGUI attempts to fix incorrectly formatted files when they are encountered. Experiment (.EXP) files are read (when possible) automatically. No warning messages are given, by this can be detected because the title bar will not that the file is "modified" immediately after the file is read. When a file is saved, it is rewritten in the correct format.

When histograms and instrument parameter files are read, their format is inspected. If an error is noted an error message is displayed, for example to the left. If OK is presses, the original file is renamed and a properly formatted file is created. In this example file test.raw is renamed to test.raw.original and a properly formatted version of test.raw file is created.

Brian Toby (Brian.Toby@NIST.GOV)
$Revision: 188 $ $Date: 2009-12-04 23:01:52 +0000 (Fri, 04 Dec 2009) $