Pdsxrrmodelbuildergui

Xrr model builder

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This window provides an interface to construct reflectivity models and computing reflectivity and fluorescent yield profiles. Various interfacial chemical distributions may be computed using the Interface Model GUI application.

`attachment:xrrmodelgui.png`_

Model

• An existing model defined in the workspace may be read in using the 'Model' menu. Hit update to make sure these lists are synced with the shell program.
• If this is a new model (or you want to rename the existing model) enter a name in the 'Save Model' field to save/write the model to the data list.
• Slab Delta Z = target slab thickness for a 'slabified' model (see Interface Model GUI and Xrr modeling for more info).
  • Note if this value is less than or equal to zero, the layer thicknesses are used as the to construct the slab model (ie the slab model = layer model)
  • Note for a slabified model using slab Delta Z > 0 the roughness values within the interface region are ignored! ie we assume that roughness is modeled with density variations
• The 'Save/Slabify' button save the model and generates the slab model if appropriate. Note you must save the model before doing any calculations within this interface

Layers

• Note layers are numbered starting with zero as the substrate. We require at minimum two layers to exist - an infinitely thick substrate (layer 0) and an infinitely thick cap layer (layer n). The cap layer should generally taken as N2 gas, ie model it as air.

• Composition = layer composition in terms of chemical components. Use the following syntax:

    {(1.0)[Si_O2]}{(1e-7)[Fe_O]}{(0.12)[Ca0.8_Na0.4_O1]}
  
  The {} is used to separate chemical components, the relative number of moles of a component is given in ().  Separate elements in a component with underscore.
  
  Note the advantage of this approach is that individual chemical components of arbitrary stiochiometry may be defined, eg. neutral species...
  

• Thickness = layer thickness in angstroms. The thickness value listed for layer 0 and layer n (the substrate and top respectively) are used for plotting / display purposes. These are assumed to be infinitely thick with respect to x-ray properties.

• Density = layer density in g/cm^3.

• Roughness = layer roughness in angstroms.

Data

• Select arrays that are defined in the shell for theta, Rdata and FYdata. Note you may also given an expression for theta array (e.g. arange(0.01,1,0.01) to define an array that goes from 0.01 to 1 degree theta by 0.01 degree steps).

Params

• Energy = Incident beam energy (eV)

• Convolution width = width of convolution function (in degrees)

• Sample length = length of the sample (mm)

• Beam vert = vert beam size (mm)

• Beam horz = horz beam size (mm)

• Model Area variation = Area flag to indicate if area calculation should be performed. ie model predicts FY change due to active area variation with theta: 0.0 no, 1.0 yes

• FY Element = Element symbol or Z value for FY calcs. Use 0 to turn off the FY calculations

• FY Energy = Energy (eV) of FY line (e.g. 'Fe Ka')

• FY Detector Angle = detector angle, ie take off angle btwn

  substrate and det. (deg)

• Theta Norm = theta value to use for yield normalization. (deg)

• Roughness Flag = roughness flag

  0.0 ignore roughness effect on t,
  1.0 use t = 1+r*exp(-(q*sigma)^2)
  Note for slabified model using slab delta > 0 (see model builder) the roughness values within the interface region are ignored!  ie we assume that roughness is modeled with density variations...
  

• Integration Delta Z = delta z for FY int (angstroms)

• FY Base base penetration depth factor = Mulitple of the substrate penetration depth to use as integration depth. Use 0.0 to ignore, ie use d[0] (given substrate thickness)

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