This is a description of the input parameters for xcrystal_bent

DABAX f0 file: 
	Select a DABAX file from where the f0 component of the structure 
	factor will be read.

DABAX f1f2 file: Select a DABAX file from where the f1f2 components of 
	the structure factor will be read.

Crystal: Select a crystal from this list of crystals.

h Miller index: obvious
k Miller index: obvious
l Miller index: obvious

Include absorption: Recommended to select *ALWAYS* Yes.

Temperature factor: Three possibilites:
       1) Enter the exp(-M) value (a positive value between 0 and 1)
       2) Enter the absolute temperatute in Kelvin, WITH A MINUS SIGN.
	  The minus sign tells to the code that the number entered
	  refers to a temperature and not to the full debye-waller exp(-M)
	  factor. The minus sign will not be considered for the numerial
	  calculations. 
	  In this case, the Debye-Waller factor is calculated 
	  as a function of the temperature, using a well-known approximation 
	  as a function of sin(theta/lambda)=1/(2d), temperature, atomic 
	  mass and Debye-temperature. In the case of crystal structures 
	  with more that one atomic sites, an independent Debye-Waller 
	  factor is calculated for each atomic site and then putting them 
	  together by averaging the M's. Values for atomic mass and 
	  Debye temperatures are obtained from the DABAX file
	  AtomicConstants.dat. For more info, see the documentation in the
	  function DebyeWaller.pro
       3) Enter a question mark (?). 
	  In this case, the code will perform the calculation as in 
	  point 2), but it will pop-up a window that will permit to modify 
	  the Debye-Waller ingredients (i.e., the sin(theta/lambda)=1/(2d) 
	  ratio, temperatute, atomic mass and Debye temperature). 
	  In the case of crystal structures with several atomic types, 
	  several values of atomic mass and Debye temperature should be entered.
	  The default values are taken from the DABAX file AtomicConstants.dat. 
	  The interest of this option is to allow the user to "improve"
	  the default value of the temperature factor, which is 
	  mostly "structure" dependent rather than dependent on the atomic 
	  types. For example, in the case of AlphaQuartz (SiO2), The Debye 
	  temperature of the oxygen is not defined by default in the 
	  AtomicConstants.dat DABAX file because oxigen does not exist in
	  crystalline state. Therefore the averaged value seems not realistic.
	  This option allows to customize the Debye temperatures from 
	  default (note that values of Debye temperature found in bibliography 
	  change significatively from one reference to another) and also allows
	  to enter average values of atomic mass and Debye temperature by 
	  entering identical values foe all atomic sites. 
	  Note that if values are changed in this window, they are not
	  saved for further runs, nor saved to input files like
	  xcrystal_bent.xop. 

Calculation Theory: Select the desired theoretical model for the bent
	crystal calculations. The options here are initialized in the 
	$XOP_HOME/data/crystal_bent_theories.dat. Some models have 
	limitations that must be kept in mind, because the application
	does not tell the user about a wrong use. 
	For example, Zachariasen theory is only for FLAT crystals (so
	the bent radius and Poisson ration values are ignored) and 
	Penning-Polder theory is only for crystals in LAUE geometry.

Geometry: Select between LAUE or BRAGG.

Min Y value: min value for the rock angle scanning in function of the 
	Y variable. 

Max Y value: max value for the rock angle scanning in function of the 
	Y variable. 

Number of points: the number of points in Y.

Photon EnergY [eV]: The photon energy in eV

Asymmetry Angle [deg]: the angle between the Bragg planes and the crystal 
	surface. It is 0.0 for the symmetrical Bragg case and 90.0 for 
	the symmetrical Laue case.

Polarization: use Sigma for polarization factor P=1.
	Pi for P=cos(2*theta_bragg)
	Total for non-polarized incident ligth P=0.5(1+cos(2*theta_bragg)).

Radius of Curvature [m]: The crystal radius in meters.

Crystal Thickness [mm]: the crystal thickness in mm

Poisson Ratio: The Poisson ration (elastic constant) for the selected crystal.
	Plase note that only homogeneous materials are considered in the
	deformation model.