tth_eta_to_k_out#

anri.diffract.tth_eta_to_k_out(tth, eta, wavelength)[source]#

Convert from (tth, eta) angles to scaled normalised \(\vec{k_{\text{out}}}\) in the lab frame.

Parameters:
  • tth (Array) – \(2\theta\) angle in degrees

  • eta (Array) – \(\eta\) angle in degrees

  • wavelength (float) – wavelength in angstroms

Returns:

k_out (jax.Array) – [3] Outgoing scaled normalised wave-vector

Notes

From equation 39 [1]:

\[\begin{split}\vec{k_{\text{out}}} = \frac{1}{\lambda} \begin{bmatrix} \cos(2\theta) \\ -\sin(2\theta) \sin(\eta) \\ \sin(2\theta) \cos(\eta) \end{bmatrix}\end{split}\]

References