Chi Gradient Correction

Apply chi COM optical correction to remove the geometrical gradient introduced by the DFXM imaging optics.

The correction subtracts a position-dependent angular shift along the horizontal direction:

\[\chi_\text{corr}(y) = \chi_\text{meas}(y) - \frac{\xi \cdot y_s}{2 \sin(\theta)}\]

where:

• \(y_s\) — horizontal position relative to image center (meters)

• \(\theta\) — half Bragg angle \(= \theta_\text{obpitch} / 2\)

• \(\xi = 1 / d_1\)

with \(d_1 = \frac{obx}{\cos(\theta_\text{obpitch})}\)

(algorithm by Marcelo Demetrio De Magalhaes).

Signals

Inputs: GrainProperties

Outputs: GrainProperties

Note

This widget has no visualisation. Connect a second Grain Plot to its output to display the corrected maps.

Prerequisites

transformation must be placed upstream to provide the pixel size in microns, which the correction algorithm requires.