Primary extinction for finite crystals. Cylinder

The results are given for the calculated profile function of the scattering curve and primary extinction factor for a crystal in the form of a cylinder as a function of its diameter τ, expressed in extinction length units and the Bragg angle. The calculations are based on the equations of the dynamical theory of X-ray diffraction. It is shown that the shift of the scattering curve maximum specified by the refraction effect depends on the crystal diameter τ. This shift for normal polarization of the incident X-ray radiation is found to be greater than that for the parallel one but at τ « 1 for both polarizations it is the same. Approximate expressions for estimation of the primary extinction factor as a function of τ at different Bragg angles are given.