==============================  xmlayer   =====================================

 Mlayer is a widget based graphical interface to calculate multilayer 
 reflectivities as a function of either the photon energy or incident angle.

 Limitations: This code only handles elements as materials (no mixtures or
 compounds implemented). It does not calculate the influence of interface 
 roughness.

 ***Note: The functionality of this code is quite limited. A much more
 performant code for multilayer calculations is IMD, available as an XOP
 extension.

 The mlayer code has been witten by J.H. Underwood at CXRO and is part of the 
 SHADOW package. M. Sanchez del Rio has modified it to directly call 
 an optical library, which gives correct values of refraction indeces when the 
 energy is scanned.  M. Sanchez del Rio has also writen this graphic interface 
 called mlayer too. 

 Schematic representation of the multilayer:

               vacuum
    |------------------------------|  \
    |          odd (1)             |  |
    |------------------------------|  | BILAYER # n_bilayers
    |          even (2)            |  |
    |------------------------------|  /
    |          .                   |
    |          .                   |
    |          .                   |
    |------------------------------|  \
    |          odd (2n - 1)        |  |
    |------------------------------|  | BILAYER # 1
    |          even (2n)           |  |
    |------------------------------|  /
    |                              |
    |///////// substrate //////////|
    |                              |



 DESCRIPTION OF THE CONTROLS IN THE MAIN WINDOW:

  File:
   MLayer input parameters: This option allows to save the current
		parameters to a file for later loading. It also allows
		to save the current parameters as defaults for being
		used when the application is initialized. In the last
		case, the file is named "application".xop (where 
		"application " is the name of the current XOP
		application) and is written in the directory pointed
		by the XOP_DEFAULTS_DIR environment variable (which
		must be set). The parameter file is ASCII and can be
		read and edited with care.
  Quit: to exit from the program

 Set_Parameters:
  Set Parameters: to define the parameters for the calculation.
		The same result is obtained pressing the "Set Parameters"
		button in the main mlayer window. 
                Please refer to the information under the HELP
		button for a complete description of the parameters. After 
		pressing the ACCEPT button, mlayer starts running.
  Set Defaults: Sets the default parameters.

  Show: Display results
    Plot Results: Plots the mlayer results.
    Show/Edit material file mlayer.f12: mlayer creates the material information
          into a file named mlayer.f12 in the case that the 
          "Material parameters" entry is set to "Create on the fly". 
          However, this mlayer.f12 file can be edited by hand and reused 
          in a next run of mlayer where the "Material parameter" entry is set 
          to "Use existing file: mlayer.f12".  
          This option allows the used to customize the materials, optical 
          constants, densities, etc.
          ****Note that the file mlayer.f12 is overwritten when the "Material 
          parameters" entry is set to "Create on the fly". It is also deleted
          when quitting the mlayer application. Therefore, be sure to save
          a security copy.

  Help:   Shows the mlayer help (this text).


 COPYRIGHT:
	MLAYER belongs to XOP package and it is distributed within XOP.
	PLEASE REFER TO THE XOP COPYRIGHT NOTICE

 REFERENCE:
	Published calculations made with XOP should refer:

	 M. Sanchez del Rio and R. J. Dejus 
         "Status of XOP: an x-ray optics software toolkit"
         SPIE Proceedings Vol. 5536 (2004) pp.171-174

         http://dx.doi.org/10.1117/12.560903

	In addition, published calculations using the mlayer aplication 
	should also cite:

	  C. Welnak, G.J. Chen and F. Cerrina, "SHADOW: a synchrotron 
          radiation X-ray Optics simulation tool",
	  Nucl. Instr. and Meth. in Phys. Res. A347 91994) 344
	or
	  SHADOW WEB Page: http://www.nanotech.wisc.edu/shadow/

 LAST MODIFICATION: srio@esrf.eu 2008-01-28