Divergence-slit intensity corrections for Bragg–Brentano diffractometers with circular sample surfaces and known beam intensity distribution

Abstract

Bragg–Brentano powder diffractometers equipped with fixed-divergence slits show a loss of intensity at small 2θ angles as a result of the overflow of the beam exceeding the sample surface. To correct this effect, geometrically derived algorithms are presented to calculate correction factors for circular sample surfaces. It is shown that the algorithms for rectangular samples can be applied to circular samples with sufficient accuracy if the value for the length of the sample is replaced by a value intermediate between the diameter of the circular sample and the length of the corresponding rectangular sample. Inhomogeneous beam intensity distribution also has serious effects on the correction factors, especially for wide divergence-slit apertures.