Secondary Extinction Correction Used in Pole Density Measurements by X-Ray Diffraction

I Tomov,K Ivanova

doi:10.1155/tsm.26-27.59

Abstract

A new X-ray diffraction method for a more accurate determination of film pole densities is developed by introducing a secondary extinction correction. To this end an equation based on the kinematic theory of X-ray diffraction and the mosaic crystal model is derived. Pole densities were computed either by using the two order reflections techniques or by the least-square method. The discussion of results shows that the correct study of film structure by X-ray diffraction requires in general the secondary extinction to be taken into account.

Highlights

In a previous paper it was established that the integrated intensity of the strongest Xray diffraction lines of textured films was lower than the kinematic theory premises (Tomov 1976)
The compatibility of the mosaic structure model with the structure of textured films is illustrated by pictures obtained in an electron microscope using PtC replicas
The cross sections show that crystalline distribution in the film is in some degree similar to that in the mosaic structure model where a requirement is postulated for X-ray optical independence and random distribution of blocks in the depth of the crystal

Summary

Introduction

In a previous paper it was established that the integrated intensity of the strongest Xray diffraction lines of textured films was lower than the kinematic theory premises (Tomov 1976). The mosaic structure model of a real crystal was proposed by Darwin, 1922, to account for its reflecting power which is affected by extinctions. The motivation to introduce a secondary extinction correction in observed intensity is related to the accuracy in pole density measurements.

Results

Conclusion