Multilayer Reflectivity vs Angle

• Top Material: Density: gm/cm^3.
  (enter negative value to use tabulated values.)
• Bottom Material: Density: gm/cm^3.
• Multilayer Period: nm.
• Gamma = Bottom layer thickness/period: .
• Interdiffusion thickness: nm (Sigma).
• Number of periods: (enter negative value for semi-infinite multilayer.)
• Substrate Material: Density: gm/cm^3.
• Polarization: (-1 < pol < 1) where s=1, p=-1 and unpolarized=0.
• Photon Energy: eV. (NOTE: Energies must be in the range 30 eV < E < 30,000 eV).

• Scan Grazing Angle from to degrees with steps (< 500).
  

To reset to default values, press this button: .

Reflectivity

The reflectivity is calculated using the Fresnel equations and the analytic formula given by V. G. Kohn in Phys. Stat. Sol. (b) 187, 61 (1995).

Material

The chemical formula is required here. Note that this is case sensitive (e.g. CO for Carbon Monoxide vs Co for Cobalt).

Density

If a negative value is entered, the chemical formula is checked against a list of some common materials. If no match is found then the density of the first element in the formula is used.

Grazing Angle

In keeping with the standard notation for the x-ray region the incidence angle is measured relative to the surface (NOT the surface normal).

Polarization

Pol = 1 corresponds to s-polarization (electric field perpendicular to the plane of incidence). Pol=-1 corresponds to p-polarization (electric field in the plane of incidence). Pol=0 for unpolarized radiation.

Interdiffusion

Interdiffusion/roughness is modeled using the Nevot-Croce factor which multiplies the reflection coefficient of each interface. This assumes an error function profile for the interface with the specified rms thickness.

Output

A GIF plot may be generated for quick viewing of the results. If you need anything fancier, the results are provided as a text file for use with your favorite plotting package.