E0	actual energy of the photons being measured
ΔE	energy correction due to axial divergence
Δy	height of one row pixels in the x-ray detector
ψ	the angle of the photon path from the perpendicular to the crystal axes (assuming crystals are aligned)
r0	the row number on the camera which is estimated to correspond to a photon path perpendicular to the crystal axes
r1	corrected central row number as a result of one pass of the calculation
z0	an estimate of the distance from the slit to the x-ray detector
z1	corrected distance from the slit to the x-ray detector as a result of one pass of the calculation
Emax	corrected energy for a ray measured at ψ = 0 (extremum of parabola)