The "Data" pulldown menu:


Activating this button enables to enter or modify crystal data by means of the following menu:

  • Select first the crystal system by clicking on its name (for example Trigonal).

  • Press the "Select space group" button. This will display a selection window:

    in which you may navigate with the vertical scrollbar on the right. To choose a space group just click on its name; then press the "OK" button.

  • Use the "Cell parameters" button. You must enter the cell parameters in the sub-menu:

    The unit is Angstrom for the length and degrees for the angles.


    This button opens a menu which allows you to give the position of the detector (usually a photographic film):

  • In the first box give the distance from the center Od of the detector to the center O of the irradiated zone. For a simulation this distance may be approximative, but for the indexation of an experimental diagram it must be given with the most accurate precision.

  • On the next line enter the width and the height of the detector (in cm).

  • For conventional experiment just select the "Transmission" or "Reflexion" button. The cursors are desactivated, because they are useless.
    Otherwhise, select the "Other" button: this will activate the cursors. In the apparatus axes (see paragraph on set of axes) the center of the detector is given by mean of two angles.
    PhiY, is the rotation angle in degrees around the OY axis; PhiZ is the rotation angle in degrees around the OZ axis:

    If necessary, the program also enables you to rotate the detector around its Xd axis by an angle DeltaXd given by means of the third cursor (left drawing):

    and then around its new Y'd axis by an angle DeltaYd given by the last cursor (right drawing).


    This button is only used when one wants to index an experimental diagram. It displays the menu:

    in whitch the cursor enables you to indicate the number of experimental spots to be used during the indexation (10 maximum).
    Clicking the "Spot coordinates" button opens the sub-menu:

    Give the coordinates (in cm) in the detector axes (see paragraph on set of axes used) of experimental spots. The first two must have low Miller indexes. In the experimental diagram, such spots are recognisable because they are isolated and located at the intersection of zone lines (ellipses, hyperboles or paraboles depending of the geometry of the experiment). For the indexation, the program uses the procedure described in the papers of Riquet & Bonnet and of Laugier & Filhol.


    This button is usefull only when one wants to compute a simulation taking into account spots intensity. It shows the following menu:

    where three kinds of X-ray sources are available:

  • an ideal source with a constant spectrum, that is producing the same intensity for all wavelengths.

  • a conventionnal X-ray tube: when choosen, the "Source characteristic" button opens a sub-menu where one may give the voltage of the tube in kV.

    The program will compute the intensity of the continous background using the Kramers formula (see Preus publication), but without taking into account the characteristic lines.

  • other: in this case supply to the program the spectrum of your X-ray source. This is done by clicking on the "Source characteristic" button: this will direct you to a sub-menu allowing you to read the file containing the spectrum. The format of this file is described in the paragraph "Format of data files".