Package reflectometry :: Package model1d :: Package model :: Module calcRefl

Module calcRefl

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Basic reflectometry calculations.

reflectivity, reflectivity_amplitude:: Slab model with optional absorption and roughness. The function reflectivity returns the magnitude squared of the waveform. The function reflectivity_amplitude returns the complex waveform.
magnetic_reflectivity, magnetic_amplitude, unpolarized_magnetic:: Slab model with supporting magnetic scattering. The function magnetic_reflectivity returns the magnitude squared for the four spin polarization cross sections [++, +-, -+, --]. The function magnetic_amplitude returns the complex waveforms. The function unpolarized_magnetic returns the expected magnitude for a measurement of the magnetic scattering using an unpolarized beam.
convolve, fixedres, varyingres: Functions for estimating the resolution and convolving the the profile with the resolution function.

Author: Paul Kienzle

Functions

reflectivity(*args, **kw)
Return reflectivity R^2 from slab model with sharp interfaces.

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reflectivity_amplitude(Q, depth, rho, mu=0, sigma=None, wavelength=1)
Returns the complex reflectivity waveform.

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magnetic_reflectivity(*args, **kw)
Magnetic reflectivity for slab models.

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unpolarized_magnetic(*args, **kw)
Returns the average of magnetic reflectivity for all cross-sections.

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magnetic_amplitude(Q, depth, rho, mu=0, wavelength=1, rho_m=0, theta_m=0, Aguide=-90.0)
Returns the complex magnetic reflectivity waveform.

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fixedres(wavelength, dLoL, dT, Q)
Return resolution dQ for fixed slits.

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varyingres(wavelength, dLoL, dToT, Q)
Return resolution dQ for varying slits.

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convolve(Qi, Ri, Q, dQ)
Return convolution R[k] of width dQ[k] at points Q[k].

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Function Details

reflectivity(*args, **kw)

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Return reflectivity R^2 from slab model with sharp interfaces. returns reflectivities.

The parameters are as follows:

Q (angstrom**-1): points at which to evaluate the reflectivity
depth (angstrom): thickness of the individual layers (incident and substrate depths are ignored)
rho (microNb): Scattering length density.
mu (microNb): absorption. Defaults to 0.
sigma (angstrom): interface roughness between the current layer and the next. The final layer is ignored. This may be a scalar for fixed roughness on every layer, or None if there is no roughness.
wavelength (angstrom): Incident wavelength (only affects absorption). May be a vector. Defaults to 1.

This function does not compute any instrument resolution corrections.

Use reflectivity_amplitude to return the complex waveform.

reflectivity_amplitude(Q, depth, rho, mu=0, sigma=None, wavelength=1)

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Returns the complex reflectivity waveform.

See reflectivity for details.

magnetic_reflectivity(*args, **kw)

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Magnetic reflectivity for slab models.

Returns the expected values for the four polarization cross sections (++,+-,-+,--).

Return reflectivity R^2 from slab model with sharp interfaces. returns reflectivities.

The parameters are as follows:

Q (angstrom**-1): points at which to evaluate the reflectivity
depth (angstrom): thickness of the individual layers (incident and substrate depths are ignored)
rho (microNb): Scattering length density.
mu (microNb): absorption. Defaults to 0.
wavelength (angstrom): Incident wavelength (only affects absorption). May be a vector. Defaults to 1.
rho_m (microNb): Magnetic scattering length density correction.
theta_m (degrees): Angle of the magnetism within the layer.
Aguide (degrees): Angle of the guide field; -90 is the usual case

This function does not compute any instrument resolution corrections or interface diffusion

Use magnetic_amplitude to return the complex waveform.

unpolarized_magnetic(*args, **kw)

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Returns the average of magnetic reflectivity for all cross-sections.

See magnetic_reflectivity for details.

magnetic_amplitude(Q, depth, rho, mu=0, wavelength=1, rho_m=0, theta_m=0, Aguide=-90.0)

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Returns the complex magnetic reflectivity waveform.

See magnetic_reflectivity for details.

fixedres(wavelength, dLoL, dT, Q)

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Return resolution dQ for fixed slits.

Angular divergence dT is (s1+s2)/d, where d is the distance between the slits and s1,s2 is the slit openings. Slits and distances should use the same units.

varyingres(wavelength, dLoL, dToT, Q)

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Return resolution dQ for varying slits.

Angular divergence dT/T is (s1+s2)/d/theta(Q(s1,s2)).