Materials Science X-Ray Analysis Laboratory

Materials Science X-Ray Analysis Laboratory
The Department of Mechanical Engineering supports and houses the X-Ray Analysis
Laboratory with two Philips x-ray diffractometers, a Materials Research Diffractometer and a
Multi-Purpose Diffractometer. The instrumentation was funded from National Science
Foundation, Division of Materials Research and the U of R with equipment help from Bausch
& Lomb. The facility is about 5 years old. The Materials Research Diffractometer, MRD, is
well suited for very high-resolution work especially for thin films and single crystal multilayer
diffraction analysis; the Multi-Purpose Diffractometer, MPD, is for powder or polycrystalline
diffraction analysis at room or non-ambient temperatures with controlled atmospheres. These
instruments have a wide range of applications: they perform qualitative and quantitative
analysis of powder diffraction data, high resolution rocking curves for electronic epitaxial
wafers, quantifying defects and perfection in high quality crystals, measuring thin film
thickness, layer densities and interface quality. In bulk and thin film materials, one can
determine stresses, textures and
grain sizes. This is made
possible by pre-aligned,
interchangeable x-ray optical
modules for pre and post
processing of the x-ray beam.
The user can select from a
variety of Prefix optics,
depending on requirements for
intensity, focusing and tolerance
for beam divergence. These
modules can be exchanged in a
matter of minutes, without the
need for complicated
dismantling, reassembly and
realignment. Generally, higher
intensity is accompanied with
increased beam divergence. For
example, an asymmetric crystal
module, using a Ge (220) 4
crystal monochromator selects
Cu Kα1 radiation at a beam
divergence as low as 18 arc-
seconds and an intensity of 5
million counts per second. The
line and spot foci have intensity
100 times higher, but at the
expense beam divergence and
dispersion. The new goniometer
has a resolution on θ and 2θ of
0.0001°. The Eulerian cradle has
5 degrees of freedom for sample orientation and position. The x-ray software is extensive with

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programs for performing comparison of the diffraction pattern with known patterns, Rietveld
phase analysis, crystal orientations, textures, residual stresses, particle size analysis, film
thickness, epitaxial layers, etc. The results obtained on complex structures are precise yet very
fast. The data can be exported to spread sheets and other graphical programs. The instruments
are housed in the refurbished x-ray room in Hopeman 111 on River Campus. Both
diffractometers are using the same software so they are operationally transparent. The MPD
and MRD units including the very high resolution modules and goniometer are used in
selected Mechanical Engineering and Materials Science courses. For further information
about the instruments and their capabilities, contact Professor Stephen Burns or Chris Pratt.
See above for the color pictures of the X-Ray Optics for Selected Applications in Materials.

Contacts: Professor Stephen J Burns, at (585) 275-4071, he can be reached in Hopeman 236
or by e-mail at burns@me.rochester.edu ; Chris Pratt, schedules operation and use, she can be
contacted at (585) 275-7807, she is in Hopeman 115 and her e-mail is Pratt@me.rochester.edu.
Below are descriptions of the two x-ray diffraction systems we use for analysis of crystalline
materials.
1. General Purpose X-ray Diffraction System for phase analysis of
polycrystalline micro or bulk samples with a high temperature, controlled
atmosphere sample stage, plus focusing and parallel beam optics.

2. Eulerian Cradle, High Resolution, Horizontal X-ray Diffraction System
with these capabilities:
o
High-Resolution X-Ray Diffraction, HRXRD, double-crystal or 4-bounce
x-ray geometry for studying large-face single crystals and epitaxial thin
films, rocking curve analysis.
o
Bragg geometry for studying stress and texture in polycrystalline solids;
crystallographic alignment of single crystals.
o
Grazing-Incidence geometry for phase analysis of polycrystalline thin
films and x-ray reflection for film thickness.
o
High resolution powder diffraction.
The following information briefly describes these x-ray diffraction systems and provides
an operational overview to facilitate user planning. Additional information is available
via the links shown at the end of this page.
System Configurations and Operational Overview
All work with the following systems and in the X-Ray Analysis Laboratory must be
performed in compliance with established practices and procedures. See x-ray safety
procedures below.

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1. General Purpose X-ray Diffraction System: Philips MPD
The general purpose X-ray diffractometer is a Philips X'Pert MPD system with a
vertical Θ-2Θ goniometer (160 mm radius). The x-ray source is a long-fine-focus,
ceramic x-ray tube with Cu anode. Normal operating power is 40 kV, 30 mA (or
less than 1.8 kW). The system optics consist of fixed divergence, anti-scatter, and
receiving slits, incident and diffracted beam Soller slits, a curved graphite
diffracted beam monochromator, and a proportional counter detector in Bragg-
Brentano, parafocusing geometry. The principal application of this system is for
phase analysis of polycrystalline samples. The Bulk Multi-Purpose Sample Stage
supports typical powder mounts but primarily accommodates large monolithic
specimens of a wide variety of sizes and shapes. In addition, specialized micro-
capillary sample tubes mounted on Supper goniometers with a rotatable sample
stage has been constructed. An environmental chamber is available for use with
non-ambient conditions. See details on the Anton-Paar TTK 450 from-193°C to
+400°C; the non-ambient sample stage can accommodate powder specimens and
small, flat monolithic solids e.g., thin film specimens in controlled atmosphere.
2. Eulerian Cradle, High Resolution, Horizontal X-ray Diffraction System:
Philips MRD
The x-ray diffractometer is a Philips X'Pert MRD PRO system with a horizontal,
high-resolution Ω-2Θ goniometer (320 mm radius). An open Eulerian cradle and
sample holder provides two additional axes of rotation (-90° < Ψ < 90°, and -360°
< Φ < +360°). The X-ray source is a long-fine-focus, ceramic x-ray tube with Cu
anode. Normal operating power is 45 kV, 40 mA (again less than 1.8 kW). The
sample stage supports monolithic and powder specimens of a wide variety of
shapes and sizes.
In the high resolution configuration, the x-ray source is used in spot-focus and the
incident-beam optic is a Bartells 4-bounce Ge (220) monochromator which
provides an intense, highly collimated beam with a divergence of ∆Θ ~ 18 arc-
seconds. The typical receiving optic is a sealed Xe proportional counter detector.
This configuration is for high-resolution, double-crystal diffraction, or HRXRD.
Alternatively, the detector can be placed behind thin film attachments using the
Ge (220) prefix optics or more divergent spot or line focus x-ray sources. The
principal application of this setup is structure analysis of epitaxial thin films
(rocking curve measurements, etc.).
In Bragg geometry, the x-ray source is used in line-focus. The incident beam optic
is a crossed-slit collimator or a programmable slit. Receiving optics consist of a
programmable receiving slit, soller slit, curved graphite monochromator, and a Xe
proportional counter detector. Typical applications include powder diffraction,
stress and texture analysis of polycrystalline solids.

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In Grazing-Incidence geometry, the x-ray source is used in line or spot focus. The
incident beam optic is typically a fixed divergence slit assembly. Receiving optics
consist of a 0.027 radian parallel plate collimator, flat graphite monochromator,
and proportional counter detector. Applications include phase analysis of
polycrystalline thin film samples and x-ray reflectivity (XRR).
Analysis Software
The principal x-ray diffraction data analysis program is X’Pert High Score and X’Pert
Plus. There are extensive software packages available on line but they are not supported
by the X-Ray Analysis Laboratory. It is suggested that any interested researcher consider
using Jade (Materials Data Inc., Livermore, CA.). Jade supports comprehensive analysis
of x-ray diffraction patterns, including Search/Match (phase identification), peak profile
fitting, indexing, unit cell refinement, etc. Other programs include Riqas (MDI) and
X'Pert Plus (Philips) for Rietveld analysis. In addition, the Philips programs X'Pert
Texture, X'Pert Epitaxy, and WINGIXA, and the Bede Scientific programs RADS and
REFS, facilitate analysis of the various data obtainable from the Special Applications and
Four-Circle X-ray Diffraction Systems.
Databases
The principal reference database is the current issue of the Powder Diffraction File
(International Centre for Diffraction Data, Newtown Square, PA.). The lab also can
obtain access to the Inorganic Crystal Structure Database (NIST, Gaithersburg, MD and
FIZ-Karlsruhe, Germany). These data are now incorporated into ICDD Powder
Diffraction Data Base V.
Additional Information
PANalytical (formerly Philips Analytical)
http://www.panalytical.com/
Anton-Paar
http://www.anton-paar.com/
International Centre for Diffraction Data: PDF Database
http://www.icdd.com/
FIZ/NIST: ICSD Database
http://www.nist.gov/srd/nist84.htm
International Union of Crystallography
http://www.iucr.org/iucr-top/welcome.html
Materials Data Inc.
http://www.materialsdata.com/

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Introduction to X-ray Diffraction
This is intended as a (very) brief introduction to some of the common x-ray diffraction
techniques used in materials characterization. It is designed for people who are novices in
this field but are interested in using the techniques in their research. Extensive and
authoritative discussions can be found in the numerous books and journal articles on this
subject. Some references are listed below.
1. Elements of Modern X-ray Physics, by Jens Als-Nielsen and Des McMorrow,
John Wiley & Sons, Ltd., 2001 (Modern x-ray physics & new developments)
2. X-ray Diffraction, by B.E. Warren, General Publishing Company, 1969, 1990
(Classic x-ray physics book)
3. Elements of X-ray Diffraction,2nd Ed., by B.D. Cullity, Addison-Wesley, 1978
(Covers most techniques used in traditional material characterization)
4. High Resolution X-ray Diffractometry and Topography, by D. Keith Bowen and
Brian K. Tanner, Taylor & Francis, Ltd., 1998 (Semiconductors and thin film
analysis)
5. Modern Aspects of Small-Angle Scattering, by H. Brumberger, Editor, Kluwer
Academic Publishers, 1993 (SAXS techniques)
6. Principles of Protein X-ray Crystallography, by Jan Drenth, Springer, 1994
(Crystallography)

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