GSAS Nickel example using EXPGUI (Intro)

Introduction

The following pages show how to use EXPGUI to perform the same tutorial refinement for Nickel powder, presented in the GSAS manual (pages 18-63 in the 9/1/94 edition) but using EXPGUI instead of EXPEDT, as done in the manual.

Note:

while it is possible to have your working GSAS files (for example the .EXP file) in a separate directory from the raw data file(s), I discourage this practice as it then becomes quite difficult to later copy or move the .EXP file from one directory or computer to another. For this reason, I suggest copying the data (.RAW) files into the directory where you will create the Experiment (.EXP) file.

For this example, I am working in directory /home/toby/work, and the data files and parameters files are in directory /home/toby/gsas/example, so I copy the Nickel data and instrument parameter file using UNIX commands:

       cp /home/toby/gsas/example/nickel.raw   /home/toby/work/
       cp /home/toby/gsas/example/inst_tof.prm /home/toby/work/

For Windows I would likely copy the files by dragging their icons between the appropriate folders.

Tutorial Outline

1. Create a GSAS Experiment File
2. Add a phase to the Experiment
3. Add data (histograms) to the Experiment
4. Change a profile parameter
5. Run POWPREF
6. Plot data using POWPLOT or LIVEPLOT
7. Setup for Least-Squares Refinement
8. Run GENLES
9. Additional Work

• Other notes (includes RAWPLOT example)

Sample files

Sample .EXP files have been saved at points through the tutorial. These are indicated in the tutorial as ".EXP snapshots". These files have been reformatted for DOS/Windows, but EXPGUI users will have no trouble using them on either platform.

• nickel2.exp -- After adding a phase to the Experiment
• nickel3.exp -- After adding data (histograms) to the Experiment
• nickel5.exp -- After running POWPREF
• nickel7.exp -- After setup for Least-Squares Refinement

Other sample files:

• nickel.raw -- data file
• inst_tof.prm -- instrument parameter file

Acknowledgements

Many thanks to Dr. Egbert Keller of the Kristallographisches Institut of the Albert-Ludwigs-Universität Freiburg for comments on this tutorial.

GSAS is written by Allen C. Larson and Robert B. Von Dreele, MS-H805, Los Alamos National Laboratory, Los Alamos, NM 87545. Problems, questions or kudos concerning GSAS should be sent to Robert B. Von Dreele at vondreele@anl.gov

GSAS is Copyright, 1984-1997, The Regents of the University of California. The GSAS software was produced under a U.S. Government contract (W-7405-ENG-36) by the Los Alamos National Laboratory, which is operated by the University of California for the U.S. Department of Energy. The U.S. Government is licensed to use, reproduce, and distribute this software. Permission is granted to the public to copy and use this software without charge, provided that this notice and any statement of authorship are reproduced on all copies. Neither the Government nor the University makes any warranty, express or implied, or assumes any liability or responsibility for the use of this software.

EXPGUI is written by Brian H. Toby of the NIST Center for Neutron Research, Brian.Toby@NIST.GOV with help from Jonathan Wasserman.

EXPGUI is not subject to copyright. Have fun with it.

Neither the U.S. Government nor any author makes any warranty, expressed or implied, or assumes any liability or responsibility for the use of this information or the software described here. Brand names cited here are used for identification purposes and do not consitute an endorsement by NIST.

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Comments, corrections or questions: crystal@NIST.gov
Last modified 18-July-2003
$Revision: 1.5 $ $Date: 2003/07/18 18:33:29 $