The effects of simultaneous reflections on single-crystal neutron diffraction intensities

Abstract

The intensity changes produced in single-crystal diffraction reflections when one or more secondary reflections occur simultaneously are discussed both theoretically and experimentally. The theory is an extension of the usual treatment of secondary extinction, based on the mosaic crystal model. An approximate solution, valid in the thin crystal limit, is in good agreement with neutron diffraction experiments on single crystals of iron. Both theory and experiment demonstrate the importance of sample geometry on the magnitude and sign of the simultaneous reflection effects. The effects may be minimized by controlling the sample geometry in addition to the usual precautions taken to reduce secondary extinction.

X-ray Multiple Diffraction Phenomenon in the Evaluation of Semiconductor Crystalline Perfection

“…The MD events assuming either ideally imperfect or highly perfect crystals have been studied by several authors, namely Chang (1984), Caticha-Ellis (1969), Moon & Shull (1964), Colella (1974) and Pinsker (1977). In the ideally imperfect crystal, small perfect regions (mosaic blocks) diffract according to the kinematical theory and the diffracted beams are the sum of incoherent intensities scattered by several mosaic blocks.…”

Treatment of secondary extinction and multiple scattering in polarized neutron scattering: an improved method. I. Method

“…4). The effects of such a situation have been described by Moon & Shull (1964) new channel into which the once-diffracted beam can be rediffracted with reflectivity rt2. These two processes reduce the observed intensity (Aufhellung).…”

“…4. The sphere of reflection showing two diffraction spots 1 and 2 as well as the origin 0 in the sphere (after Moon & Shull, 1964).…”

Examination of n-beam interaction: X-ray experiment and simulation for KMnF3

“…The other is, in contrast, based on the kinematical theory, and mainly related to the correction of the intensity data for structure determination. The papers by Tanaka & Saito (1975) and LePage & Gabe (1979), both following the intensity equation given by Moon & Shull (1964), are examples of the second branch. Overall effects on the intensity data and consequently on the structure determination are examined.…”