 
 
     D I X I E  -  Qu'est-ce donc ?
     ------------------------------
 
 
            The preceding page demonstrates how one is greeted when he
 
 enters the command DIXIE/G on a well educated Perkin Elmer. DIXIE simply
 
 stands for DIX, IX and E, e.g. Display Ix and  Energy (Routhian). It
 
 originates from IX (used to calculate  Ix and aligned angular momentum) and
 
 from  DIX (which was used to display them) both written by our skillful
 
 David. DIXIE will do the same things IX and DIX were doing but without the
 
 inconvenients of having to run from one terminal to another each time one
 
 wanted to modify the moments of inertia for the reference nucleus. Many will
 
 ask why this had not been done before... There are whole new features too:
 
 DIXIE will calculate Ix and ix, and will also calculate the first and second
 
 moment of inertia and the experimental Routhian, for the same price ! This
 
 is so useful that we are still wondering why it was left over up to now.
 
 
     Comment ca marche ?
     -------------------
 
 
   To use DIXIE one has to setup an input file first. To performs its
 
 calculations DIXIE needs to know the gamma-ray energies of course but it also
 
 needs a first estmate for the reference moment of inertia (I0 and I2), then
 
 the spin (I) and the absolute energy (E0) of the last level of the cascade and
 
 finally the K of the band. Here is how an input file must be setup:
 
    First line: I0,I2
   Second line: Ifinal,K,E0
    Third line: Egamma-1
                  .
                  .
                  .
      n+3 line: Egamma-n
      n+4 line:                  (spaces only)
      n+5 line: I0,I2            (for a second band)
      n+6 line: Ifinal,K,E0
      n+7 line: Egamma-1
                  .
                  .
                  .
 
                 ect...
 
 
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   See one of the next pages for an example. As many band as one needs
 
 can be stacked in one file. An output file created by DIXIE can also be given
 
 to DIXIE as an input file. DIXIE will recongnize its work. The input file
 
 format is similar to the one IX was using. Only E0 was added to allow DIXIE
 
 to calculate the experimental Routhian.
 
 
 
     La cle du pouvoir
     -----------------
 
    All the features of DIXIE can be accessed from a "keypad menu" which is
 
 displayed on the sceen at all time. Each key performs a simple action. For
 
 example, one can display Ix by pressing the PF4 key (the "Display Ix" key).
 
 Here is what each key does:
 
 
 "Display Ix":  Displays the values of Ix (the projection of the spin along
 
                the axis of rotation) vs homega or homega square. Ix is
 
                calculated using the formalism sumerized by de Voigt et al.
 
                in Reviews of Modern Physics, 56, 1983, pp 988-989.
 
                Ix = sqrt( I(I+1) - K^2 ) where I is the average spin of the
 
                levels linked by the transition:
 
                   ---------------- I initial  (=I+1)
                           |
                           |
                           |
                   - - - - | - - -  I
                           |
                           |
                           V
                   ---------------- I final    (=I-1)
 
 
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                                                        Egamma
                 In this scheme homega is:  hw = ---------------------
                                                 Ix(Iinit) - Ix(Ifinal)
 
 "Display Alignment":  Displays the aligment vs homega or homega square.
 
                       It is calculated from Ix by subtacting from it a
 
                       reference which is parametrised by I0 and I2:
 
                       ix = Ix - [ I0 + I2(hw)^2 ]hw
 
 "Display Routhian":  Displays the experimental Routhian. It is computed using
 
                      E(I) (the average absolute energy of the level I and Ix):
 
                      E'exp = E(I) - hw Ix(I)
 
                      and is further subtracted by the reference:
 
                      E'ref = -.5 I0 (hw)^2 -.25 I2 (hw)^4 +.125/I0
 
                      The values for the Routhian are then negative and one
 
                      must set the Y scale accordingly before trying to display
 
                      it (see "Change Y0").
 
 "Display 1st Moment":  This will display the first moment of inertia I(1) vs
 
                        homega or homega square. It is given by:
 
                                  2I + 1
                        I(1) = ------------
                               Eg(I+1->I-1)
 
 "Display 2nd Moment":  This will display the second moment of inertia vs
 
                        homega or homega square. It is given by:
 
                                           4
                        I(2) = ---------------------------
                               Eg(I+1->I-1) - Eg(I-1->I-3)
 
 "Toggle w <-> w^2":  Toggle the x axis between homega and homega square.
 
 "Change X0", "Change NX", "Change Y0" and "Change NY":  These commands
 
              behave exactly as those GELIFT taught us. When one press one of
 
              these key, the old value is written and a prompt is given for a
 
              new one. If one types return without giving any new value, the
 
              old one is retained.
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 "Change I0 and I2":  This will change the value of the reference and will
 
                      recalculate ix and the Routhian. First the current
 
                      values of I0 and I2 are written and requests for the new
 
                      values are made. Return with no answer will kept the
 
                      old values untouched.
 
 "Call Cursor":  Like the GELIFT call cursor command this command allows
 
                the user to point at data points to obtained their coordinates.
 
 "Expand Display":  This command will prompt for an interval using the cursor
 
                    and will display the last data with an expanded x axis.
 
 "Fit a Line":  This command will prompt for an interval like expand cursor
 
                does and will trace the best line through the selected data
 
                points. It is very useful to extrapolate Routhian and/or to get
 
                its slope.
 
 "Next Data":  This will read from the input file the next set of data. If
 
               the end of the file is reached, the name of a new data file is
 
               asked. Return will reopen the previous data file. If I0 and I2
 
               in the data set are different from the one beeing used, DIXIE
 
               will ask to the user if he wants to change them.
 
 "New Data File":  This will allow the user to change the input data file.
 
 "Write Data to Disk File":  This commands writes to disk everythings it
 
                             knows. An example of such a file follows. This
 
                             type of file can also be used as an input file.
 
 "Exit":  Will do so...
 
 
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     La cerise sur le sorbet
     -----------------------
 
 
    The following pages complete this presentation. The next one is
 
 representation of the keypad commands. Then comes the example of an input
 
 file refered to above. It was taken from Victor's data for Platnium 185.
 
 A typical output file from DIXIE and some hard copies from a session with
 
 DIXIE where added to show what DIXIE can do for you. Have fun working with
 
 DIXIE, it was fun to write.
