lorentzian_precession#

diffsims.utils.shape_factor_models.lorentzian_precession(excitation_error, max_excitation_error, r_spot, precession_angle)[source]#

Intensity profile factor for a precessed beam assuming a Lorentzian intensity profile for the un-precessed beam. This is equation (10) in reference [1].

Parameters:

excitation_error (array-like or float) – The distance (reciprocal) from a reflection to the Ewald sphere
max_excitation_error (float) – The distance at which a reflection becomes extinct
r_spot (array-like or float) – The distance (reciprocal) from each reflection to the origin
precession_angle (float) – The beam precession angle in radians; the angle the beam makes with the optical axis.

Returns:

intensity_factor – Vector representing the rel-rod factor for each reflection

Return type:

array-like or float

References

[1] L. Palatinus, P. Brázda, M. Jelínek, J. Hrdá, G. Steciuk, M. Klementová, Specifics of the data processing of precession electron diffraction tomography data and their implementation in the program PETS2.0, Acta Crystallogr. Sect. B Struct. Sci. Cryst. Eng. Mater. 75 (2019) 512–522. doi:10.1107/S2052520619007534.