   Exercise: Refinement of standard samples in TOF diffractometers
   ----------------------------------------------------------------
   Here we provide a series of folders containing TOF powder diffraction data of standard
   samples for calibrating ISIS instruments. The data are provided just for training and
   learning how to create IRF files for TOF.
   
   We reproduce here some information from fp2k.inf document:
   
 ----------------------
 >> 18 April   2011:      Changes in R-Bragg and the IRF-files for TOF
 ----------------------

   - The calculation of R-Bragg and RF-factor has been changed in order to take into account
     the fact that in many cases in profile intensities have been normalised to values that
     are much smaller than "counts". This eliminates the necessity to multiply the profile
     intensities and standard deviations by a factor of the order of 1000 in order to obtain
     correct values for R-Bragg and RF. The change has no effect for intensities corresponding
     to counts.

   - In all TOF cases Res=5 and Res=6 the new keyword ZD2TOF (and ZD2TOT) can be given instead
     of D2TOF (and D2TOT). In such cases the zero point value is given before Dtt-values.
     Examples:
     For Res=5 the line  "ZD2TOF  Zero  Dtt1  Dtt2" may replace the old line "D2TOF  Dtt1  Dtt2 [Zero]"

     For Res=6, the following lines may replace D2TOF and D2TOT lines
!        Zero       Dtt1
ZD2TOF   1.23     7478.332
!       Zerot      Dtt1t        Dtt2t    x-cross    Width
ZD2TOT   0.48     7459.7754    19.9522    1.2640    2.3630

   - Changes in the comments of the PCR file for Npr=10 have been introduced to be consistent
     with  Npr=9,13 if an IRF-file is used. Now only the shifts w.r.t. IRF values are refined
     in the PCR file if Res=6.

   - The most important changes concern lookup tables for profile functions Npr=9 and Npr=13
     (Res=5). Two new keywords LIST_SHIFT and LIST_SIG_GAM_ALF_BET_SHIFT have been introduced
     (see note of 25 October 2009 and 12 December 2005 for previous changes and details).
     As for other cases the keywords are followed by the number of points given in the lines
     following the keyword line.

      LIST_SHIFT  npoints  (in this case, the instrumental SIGMA, GAMMA and ALFBE parameters should be given)
      LIST_SIG_GAM_ALF_BET_SHIFT  npoints ( no SIGMA, GAMMA or ALFBE keywords should appear in the IRF file)

     In all LIST cases the keyword and number of points (npoints) is followed by a list of npoints lines
     containing:
             d-spacing, Shift (in micro-seconds)              (for LIST_SHIFT)
             d-spacing, sigma^2, gamma, alpha, beta and Shift (for LIST_SIG_GAM_ALF_BET_SHIFT)


 ----------------------
 >>  25 October 2009:     Output of IRF files for TOF and new lookup tables for treating
 ----------------------   the resolution of TOF diffractometers

    - A file called "TOF_irf_file.irf" is automatically created if no resolution file is used for
      treating a TOF diffraction pattern. This file contains the information needed to use it as
      an IRF file using Res=5 (see next item) after some minor editing.

    - New keywords for TOF when Res=5 using the profile function Npr=9 have been introduced. This
      concerns the cases of lookup tables. Up to now, only the the case of the alpha and beta, rise
      and decay, parameters was possible to be treated with a lookup table (see note of 12 December 2005)
      using the keyword LISTALFBET followed by the number of points and a list of d-spacing, alpha and
      beta values. Now we can use also sigma^2 (Gaussian variance) and gamma (FWHM of Lorentzian component)
      or the whole set of the four items: sigma^2, gamma, alpha, beta as a function of d-spacing.

      The keywords available for using lookup tables are:

      LISTALFBET  npoints  (in this case, the instrumental SIGMA and GAMMA parameters should be given)

      LISTSIGGAM  npoints  (in this case, the instrumental ALFBE parameters should be given)

      LIST_SIG_GAM_ALF_BET  npoints    ( no SIGMA, GAMMA or ALFBE keywords should appear in the IRF file)

      In all LIST cases the keyword and number of points (npoints) is followed by a list of npoints lines
      containing:
                  d-spacing, alpha and beta                 (for LISTALFBET)
                  d-spacing, sigma^2 and gamma              (for LISTSIGGAM)
                  d-spacing, sigma^2, gamma, alpha and beta (for LIST_SIG_GAM_ALF_BET)

      The last case is generated by FullProf itself in the case of not using an IRF file (see previous item)
      The maximum number of points should be lower than 400 (npoints_max=400).

 ---------------------
 >> 10 February 2004 : IRF files. DLIM in TOF. Changes in profile matching
 >>                    modes. Generation of *.int files for TOF. New files
 >>                    of extension *.seq putting Rpa=-2 in sequential refinements.
 ---------------------

    Several changes have been performed in the current version of
    FullProf.

 - The keyword "WAVE" followed by three real numbers can now be included
   in IRF files corresponding to Res=4, before giving the number of points
   to be read.
   Example (header of the file):
          My resolution file: diffractometer with Cu ka1-ka2
          !This is a comment: File prepared using LaB6 and WinPLOTR
          WAVE 1.5406 1.5444 0.497
          25
          ...........

   Another IRF format is available. Putting Res=8 a similar file to that
   described for Res=4 is read. The only difference is that in each line
   the asymmetry parameters S_L,D_L due to axial divergence (L. Finger,
   et al.) are also read. In principle all the asymmetry parameters
   should have the same values but this has been included in each line to
   take into account other possible causes of asymmetry. Then the lines
   read with Res=4 have as items "2theta  HG  HL" and those read with
   Res=8 are of the form  "2theta  HG  HL  S_L  D_L".

 - In the IRF files for Res=5 (T.O.F.) the keyword "NPROF" has been included.
   It tells the program what kind of profile function has been used to
   create the IRF file itself. NPROF is followed by an integer that can
   be 9 for the back-to-back exponentials  or 13 for the Ikeda-Carpenter
   function convoluted with a pseudo-Voigt.
   In the lines starting with the keyword D2TOF a third item (in addition
   to Dtt1_i and Dtt2_i) can be read representing the zero point of the bank
   in micro-seconds.

 - Some tuning of special variables controlling the range in different banks
   of TOF multi-pattern refinement has been performed. This concerns mostly
   the cutting at low d-spacing and the way of generating satellite reflections
   at low Q (high d-spacing) for propagation vectors near the zone boundary.
   The range of TOF in the instrumental resolution files has a higher priority
   than the effective range read from the input data file.

 - The generation of *.int files for simulated annealing in TOF has been
   totally revised. Instead of storing sums of integrated intensities in a
   cluster (j.Lp.C.F2), we use just sums of F2 (without multiplicities and
   Lorentz factors) in order to get the same units for data coming from
   different banks. The reflections in *.int files, for each bank, are
   re-ordered in order to put on top the most important ones (those at low Q).

 --------------------
 >> 12 October 2003  : IRF files for TOF.                  
 --------------------


 - The refinement flags concerning different patterns are now output explicitly
   in the PCR file even if the user has not given zero values.
   Now the output of the NPATT line adopts the following aspect:

   NPATT      3       1 1 1   <- Flags for patterns (1:refined, 0: excluded)

   When using zero flags for some patterns remember that the weighting
   factor of each pattern is changed by the program, so that the sum of
   weights of all considered patterns is equal to 1. If one wants to re-start
   with more patterns, check the weighting factors before running the program.

 - The resolution function of the different banks corresponding to a TOF diffractometer
   can now be included in a single file. One has to repeat the name of the file for
   each pattern in the PCR file. The different bank information has to be separated
   by the keyword "END" (without quotes) within the IRF file.
   Now the intrumental parameters + refined shifts are output as comments in the
   PCR file when an IRF file is used in TOF.
   The keyword TOFRG is now used for limiting the TOF read in the input data file.
   Only the points satisfying: TOF_min <= TOF <= TOF_Max, are used in the program.
   Examples of IRF files will be provided in the subdirectory "IRF-files"
   of the FullProf suite directory.

 ------------------
 >> 10 May  2003     : New keywords in IRF files. 
 ------------------

 - New keywords have been introduced for IRF files. The interface program EdPCR
   is now able to write an IRF using a template. A subdirectory called IRF-files
   will be created on installing the FullProf suite where several examples of
   IRF files can be found.


