The purpose of this program is to save a GEM WorkspaceArray to a data file of the type required by the GSAS Rietveld refinement software. To use this program type writegsas data where data is the  WorkspaceArray to be saved (this may have been produced by the programs GEMSQRAW, READFILE or GEMFOCUS). The program will ask you for a minimum and maximum time-of-flight for the data. In most cases a range of 3000-19900 will be suitable. For the GSAS software it is advisable that the y-values of the data are of order one, say in the range 0.1-10.0. If your data have y-values which differ greatly from one then you should multiply your data by a suitable factor first. This may be done by typing 
, for example. The output file will be named like gem12345.gsas

The files created by WRITEGSAS may be read back into OpenGenie by typing 
or old=loadgsas(), for example.


If you intend to refine data from a file created by the WRITEGSAS command then it is essential that you use a parameter file with a consistent calibration. If you use a parameter file which was created for use with a data file written by the ariel program, then the calibration will not be consistent. Here you can download parameter files for use with data files created by the WRITEGSAS command...

File Suitable for these run numbers
gem_024.prm 10586-12302
gem_051.prm 16505 onwards


Last updated on 14 Dec 2005 by Alex Hannon (a.c.hannon@rl.ac.uk)