Package reflectometry :: Package reduction :: Module qxqz

Module qxqz

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Translate coordinates between real and reciprical space.

Functions

ABL_to_QxQz(sample_angle, detector_angle, wavelength)
Compute Qx,Qz given incident and reflected angles and wavelength

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QxQzL_to_AB(Qx, Qz, wavelength)
Guess incident and reflected angles given Qx, Qz and wavelength.

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QxQzA_to_BL(Qx, Qz, alpha)
Guess detector angle and wavelength given Qx, Qz and sample angle.

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test()

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Function Details

ABL_to_QxQz(sample_angle, detector_angle, wavelength)

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Compute Qx,Qz given incident and reflected angles and wavelength

Returns (Qx,Qz)

If all inputs are scalars the result will be a scalar.

QxQzL_to_AB(Qx, Qz, wavelength)

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Guess incident and reflected angles given Qx, Qz and wavelength.

This transform is not invertible: for any Qx, Qz there are two separate choices for sample angle and detector angle which give the same Q. We choose the one for which detector angle matches the sign of Qz.

Returns sample angle, detector angle

Sample angle is also called the incident angle, theta_i. Dectector angle is incident angle plus reflected angle, or theta_i + theta_f.

If all inputs are scalars the result will be a scalar.

Error is in the order of 1e-12 for off-specular coordinates.

QxQzA_to_BL(Qx, Qz, alpha)

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Guess detector angle and wavelength given Qx, Qz and sample angle.

The detector angle is branch cut between -180 and 180 degrees.

Returns detector angle, wavelength

Sample angle is also called the incident angle, theta_i. Dectector angle is incident angle plus reflected angle, or theta_i + theta_f.

If all inputs are scalars the result will be a scalar.

Error is in the order of 1e-12 for off-specular.