ess.estia.conversions.reflectometry_q_x#

ess.estia.conversions.reflectometry_q_x(wavelength, theta, sample_rotation)[source]#

Compute momentum transfer in off-specular direction.

\[Q_x = \frac{2 \pi}{\lambda} (cos(\theta_o) - cos(\theta_i))\]

Where \(\theta_o\) is the reflection angle (theta()) and \(\theta_i\) is the incident angle on the sample surface.

Note that here we assume the incident angle is equal to sample_rotation.

Source: Frédéric Ott, “Off-specular data representations in neutron reflectivity”

Parameters:

  • wavelength (Variable) – Wavelength values for the events.

  • theta (Variable) – Angle of reflection for the events.

  • sample_rotation (Variable) – Angle of incidence.

Returns:

Variable – Qx-values.