Eppley Institute for Cancer Research

University of Nebraska Medical Center

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Lorentz Correction

The Lorentz correction is a result of the fact that the Ewald sphere has the same angular speed throughout as it spins and intersects the reciprocal lattice, but has different linear speeds at different points on the sphere. Think about the fact that a point at the "top" of the sphere has to go a shorter linear distance than a point at the equator of the sphere. Moving at a faster speed means less intensity will likely be seen than for the slower moving reflections.

The formula for the Lorentz correction used by BEAM-ish is shown below:

In the formula

X - horizontal distance from the the beam center where the phi rotation is considered about the horizontal axis

Y - vertical distance from the beam center

Z - crystal to detector distance