scholarly journals Effects of Misalignment of Parallel Beam Optics on Thin Film Stress Analysis

2014 ◽  
Vol 996 ◽  
pp. 141-146
Author(s):  
Nicholas Norberg ◽  
Arnold C. Vermeulen

Collecting reliable data is crucial in the research of residual stresses in thin films using X-ray diffraction. The parallel beam geometry has advantage of reliability compared to focusing beam geometry. Though care must be taken to the alignment. A small alignment error may cause a significant error in the stress value. We will show the sensitivity for the misalignment of the parallel beam optics, discuss requirements on hardware alignment and demonstrate a software correction for the presence of remaining hardware errors.

1988 ◽  
Vol 32 ◽  
pp. 311-321 ◽  
Author(s):  
R.A. Larsen ◽  
T.F. McNulty ◽  
R.P. Goehner ◽  
K.R. Crystal

AbstractThe use of conventional θ/2θ diffraction methods for the characterization of polycrystalline thin films is not in general a satisfactory technique due to the relatively deep penetration of x-ray photons in most materials. Glancing incidence diffraction (GID) can compensate for the penetration problems inherent in the θ/2θ geometry. Parallel beam geometry has been developed in conjunction with GID to eliminate the focusing aberrations encountered when performing these types of measurements. During the past yearwe developed a parallel beam attachment which we have successfully configured to a number of systems.


2011 ◽  
Vol 681 ◽  
pp. 115-120 ◽  
Author(s):  
Matteo Ortolani ◽  
Cristy Leonor Azanza Ricardo ◽  
Andrea Lausi ◽  
Paolo Scardi

The main instrumental characteristics of MCX, the new beamline at the Italian synchrotron Elettra in Trieste, are presented. Design and geometrical set-up are well suited to the X-ray diffraction stress and texture analysis of thin films and surfaces, and are such to guarantee a full control of the main instrumental errors. Besides exploiting the typical features of synchrotron radiation, like high brilliance, tuneable beam energy and optimal beam geometry, MCX can also host tools for in-situ studies, like X-ray diffraction during four point bending. A few examples of current applications are shown.


2002 ◽  
Vol 35 (2) ◽  
pp. 196-206 ◽  
Author(s):  
U. Welzel ◽  
M. Leoni

Corrections for instrumental aberrations of X-ray diffraction texture measurements (pole-figure measurements) conducted in quasi-parallel-beam geometry using an X-ray lens have been investigated on the basis of measurements on (texture-free) reference samples. It has been shown that a defocusing correction, which is a major correction in the case of pole figures recorded with divergent-beam geometries, is not necessary when a parallel beam, produced by an X-ray lens, is used. In this case, the major instrumental sources of error stem from the illumination of areas outside the sample surface,i.e.the finite sample size, and the finite area of the detector, both giving rise to a reduction of the recorded signal. Two correction procedures for this reduction, an experimental one and a numerical one, have been tested and are described.


1976 ◽  
Vol 20 ◽  
pp. 393-402 ◽  
Author(s):  
Richard M. Chrenko

X-ray residual stress measurements have been made with a commercial portable X-ray diffraction apparatus that uses parallel beam optics and that was specifically designed for residual stress measurements. This machine differs from X-ray diffraction units using the usual parafocusing geometry in several respects, most notably reduced sample placement errors and larger sample sizes that can be accommodated. Two special modes of operation are available and will be discussed. These are the ability to use the side inclining method for stress analysis and the ability to use an oscillating ψ motion, the latter mode being useful for examining large grain size materials.


2002 ◽  
Vol 17 (2) ◽  
pp. 81-93 ◽  
Author(s):  
Licai Jiang ◽  
Zaid Al-Mosheky ◽  
Nick Grupido

Multilayer optics is one of the widely applied optics for conditioning an X-ray beam in the region of X-ray diffraction. Multilayer optics offers a well-balanced performance. The beam conditioned by a multilayer optic is characterized by low divergence, good spectrum purity, and high intensity. This article will start with a short historical note of the development of X-ray multilayer and a summary on the basic performance characteristics of X-ray multilayer, then move on to the discussion on the design principle of one- and two-dimensional optics. Both parallel beam optics and focusing optics will be addressed. As examples, selected applications of multilayer optics are also briefly discussed. Finally, the main problems associated with the application of multilayer optics are identified and the future developments are discussed.


2008 ◽  
Vol 41 (1) ◽  
pp. 124-133 ◽  
Author(s):  
M. Wohlschlögel ◽  
T. U. Schülli ◽  
B. Lantz ◽  
U. Welzel

Instrumental aberrations of a parallel-beam diffractometer equipped with a rotating anode X-ray source, a single-reflection collimating multilayer optic and a parallel-plate collimator in front of the detector have been investigated on the basis of standard measurements (i.e.employing stress- and texture-free isotropic powder specimens exhibiting small or negligible structural diffraction line broadening). It has been shown that a defocusing correction, which is a major instrumental aberration for diffraction patterns collected with divergent-beam (focusing) geometries, is unnecessary for this diffractometer. The performance of the diffractometer equipped with the single-reflection collimating multilayer optic (single-reflection mirror) is compared with the performance of the diffractometer equipped with a Kirkpatrick–Baez optic (cross-coupled Göbel mirror) on the basis of experimental standard measurements and ray-tracing calculations. The results indicate that the use of the single-reflection mirror provides a significant gain in photon flux and brilliance. A high photon flux, high brilliance and minimal divergence of the incident beam make the setup based on the single-reflection mirror particularly suitable for grazing-incidence diffraction, and thus for the investigation of very thin films (yielding low diffracted intensities) and of stress and texture (requiring the acquisition of large measured data sets, corresponding to the variation of the orientation of the diffraction vector with respect to the specimen frame of reference). A comparative discussion of primary optics which can be used to realise parallel-beam geometry shows the range of possible applications of parallel-beam diffractometers and indicates the virtues and disadvantages of the different optics.


2005 ◽  
Vol 490-491 ◽  
pp. 131-136 ◽  
Author(s):  
Arnold C. Vermeulen

The sensitivity of various combinations of optics to alignment errors is investigated. A large number of tests with varying specimen displacements and incident beam misalignments are performed for both line and point focus residual stress optics combinations. This investigation includes experiments with mixed combinations of typical “focusing beam optics” and “parallel beam optics”. It is verified if the peak positions are either sensitive to height errors like for the focusing beam geometry or insensitive like for the parallel beam geometry. The peak position sensitivity is classified for all combinations of incident beam and diffracted beam optics modules.


2021 ◽  
Vol 3 ◽  
pp. 53-65
Author(s):  
С.П. Осипов ◽  
И.Г. Ядренкин ◽  
С.В. Чахлов ◽  
О.С. Осипов ◽  
Е.Ю. Усачёв

A computational model of X-ray computed tomography with a density estimation function in the parallel beam geometry is proposed. The model includes blocks for simulating and correcting sinograms and reconstructing slices of test object. When generating sinograms, the parameters of the test object, source and detector of X-ray radiation are taken into account. Algorithms of simulation are implemented in the MathCad software and are tested on virtual test objects.


1992 ◽  
Vol 36 ◽  
pp. 373-377
Author(s):  
Mary F. Garbauskas ◽  
Donald G. LeGrand ◽  
Raymond P. Goehner

AbstractThe physical properties of polymer blends consisting of one or more crystallizable components are affected by the microstructure of these materials. In particular, the degree of crystallinity can be influenced by processing parameters, and the crystallinity, as well as the phase distribution, may vary as a function of depth through an injection molded part. Conventional x-ray diffraction techniques can provide information regarding both phase composition and degree of crystallinity, but, because of the relative transparency of these materials to wavelengths generally available in the laboratory, these techniques provide information representative of only the bulk. By employing parallel beam optics at varying grazing incidence angles, the x-ray sampling depth can be varied without loss of resolution, This technique can be used to vary the effective analysis depth from the top several hundred angstroms for low grazing incidence to centimeters for transmission diffraction patterns, Grazing incidence techniques have found initial application in the characterization of thin metallic and ceramic films. This paper demonstrates the feasibility of using parallel beam optics to depth profile low atomic number materials. The specific application of this technique to the characterization of injection molded polymers, including a blend of bisphenol-A polycarbonate (PC) and polybutylene terephthalate (PBT), will be presented.


1988 ◽  
Vol 32 ◽  
pp. 481-488
Author(s):  
W. Parrish ◽  
M. Hart

AbstractComparison of results using synchrotron radiation and X-ray tubes requires a knowledge of the fundamentally different profile shapes inherent in the methods. The varying asymmetric shapes and peak shifts in focusing geometry limit the accuracy and applications of the method and their origins are reviewed. Most o f the focusing aberrations such as specimen displacement, flat specimen and θ-2θ mis-setting do not occur in the parallel beam geometry. The X-ray optics used in synchrotron parallel beam methods produces narrow, symmetrical profiles which can be accurately fit with a pseudo-Voigt function, They have the same shape in the entire pattern. Only the width increases as tanθ due to wavelength dispersion but with higher resolution systems dispersion can be eliminated. The constant instrument function contribution to the experimental profile shape is an important advantage in studies involving profile shapes, e.g., small particle sizes and microstrains, and accurate integrated intensities. The absence of systematic errors leads to more precise lattice parameter determinations.


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