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****************   Documentation for SHADOW   *****************
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  PROGRAM AUTHOR  :  S. A. Howard,
                     Materials Data Inc.,
                     P. O. Box 791,
                     Livermore,
                     CA 94551-0791,
                     UNITED STATES.
                     Tel. : (1) 415-449-1084
                     Fax. : (1) 415-373-1659


 -------------------------------------------------------



     SHADOW - a general pattern analysis program.



       The two areas of SHADOW which we aim to utilise
  here are :

  (1). Peak-searching,
  (2). Peak-fitting by refinement of peak parameters.



  PLEASE NOTE : The graphics package associated with SHADOW
                has not yet been incorporated into the CCP14 
  Suite on account of portability problems.  However, it is 
  intended to make this addition as soon as possible. 




  INPUT DATA FILES  :  Three example input data files are         
                       provided in the current directory,
  namely "SIBAG2.XDA", "SRM0509.XDA" and "GSA0509.XDA".


  The format of all of these files is :

    line 1     -  experimental title (text).

    line 2     -  date and time of experiment (text).

    line 3     -  2theta value at start of 2theta range (degrees),
                  2theta value at end of angular range (degrees),
                  angular increment in 2theta (degrees) and
                  step time (seconds).

    line set 4 -  counts at each angular setting, expressed in
                  an array with 10 columns.  Counts for increasing
                  2theta are found by reading across each row, and
                  carrying on to the next row.




  OPERATIONAL DETAILS :  


    * PEAK-SEARCHING ...

        To invoke the program, simply type "shadow" from the same
      directory as the appropriate ".XDA" input data file, and then
      follow the prompts given by the program.  At the appropriate
      prompt, users should select the "s" option from the list of
      SHADOW functions, to perform peak-searching.

        PLEASE NOTE - if the default option is not obtained simply
      by pressing RETURN following the prompt, then the user should
      try pressing "/" followed by RETURN.

        The file "pksearch.txt" in the current directory is a
      complete listing of the screen output during a run of SHADOW
      to search for peaks in the range 20 degrees to 80 degrees,
      based on the data from the pattern file "SIBAG2.XDA".
      
        Users may like to repeat this process on the pattern files
      "SRM0509.XDA" and "GSA0509.XDA".


    * PEAK-FITTING ...

        Having obtained the approximate peak positions as above,
      the user may now use the "r" option from the list of functions
      performed by SHADOW to refine peak parameters by profile        
      fitting.  The user need not exit the program in order to carry
      on with the peak-fitting option.  

        The file "pkfit.txt" in the current directory is a complete
      listing of the screen output during a run of SHADOW to refine 
      peak parameters.  The peak at 2theta = 28.4432 degrees from the 
      earlier peak-search stage is used as an example here.

        Users may like to repeat this process on the pattern files
      "SRM0509.XDA" and "GSA0509.XDA".




  DEFAULT VALUES  :  The file "SHADOW.DFT" contains keywords and
                     parameter values that may be used as defaults by
                     the SHADOW program.  This file is located in the
                     current directory.          
     
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