X-ray Microprobe for Fluorescence and Diffraction Analysis
- ORNL
X-ray diffraction (see unit 1.1) and x-ray excited fluorescence analysis are powerful techniques for the nondestructive measurement of crystal structure and chemical composition. X-ray fluorescence analysis is inherently nondestructive with orders of magnitude lower power deposited for the same detectable limit as with fluorescence excited by charged particle probes (Sparks, 1980). X-ray diffraction analysis is sensitive to crystal structure with orders-of-magnitude greater sensitivity to crystallographic strain than electron probes (Rebonato, et al. 1989). When a small-area x-ray microbeam is used as the probe, chemical composition (Z>14), crystal structure, crystalline texture, and crystalline strain distributions can be determined. These distributions can be studied both at the surface of the sample and deep within the sample (Fig. 1). Current state-of-the-art can achieve an {approx}1 mm-D x-ray microprobe and an {approx}0.1 mm-D x-ray microprobe has been demonstrated (Bilderback, et al., 1994). Despite their great chemical and crystallographic sensitivities, x-ray microprobe techniques have until recently been restricted by inefficient x-ray focusing optics and weak x-ray sources; x-ray microbeam analysis was largely superseded by electron techniques in the 50's. However, interest in x-ray microprobe techniques has now been revived (Howells, et al., 1983; Ice & Sparks, 1984; Chevallier, et al., 1997; Riekel 1992; Thompson, el al., 1992; and Making and Using... 1997) by the development of efficient x-ray focusing optics and ultra-high intensity synchrotron x-ray sources (Buras & Tazzari, 1984; Shenoy, et al., 1988). These advances have increased the achievable microbeam flux by more than 11 orders of magnitude (Fig. 2) (Ice, 1997); the flux in a tunable 1 mm-D beam on a 'so called' 3rd-generation synchrotron source such as the APS can exceed the flux in a fixed-energy mm2 beam on a conventional source. These advances make x-ray microfluorescence and x-ray microdiffraction analysis techniques some of the most powerful techniques available for the nondestructive measurement of chemical and crystallographic distributions in materials. This unit reviews the physics, advantages, and scientific applications of hard x-ray (E > 3 keV) microfluorescence and x-ray microdiffraction analysis. Because practical x-ray microbeam instruments are extremely rare, a special emphasis will be placed on instrumentation, accessibility, and experimental needs which justify the use of x-ray microbeam analysis.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1008360
- Resource Relation:
- Related Information: Published in Methods in Materials Research: A Current Protocols Publication
- Country of Publication:
- United States
- Language:
- ENGLISH
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Subgroup report on hard x-ray microprobes
Analysis of heterogeneous materials with x-ray microfluorescence and microdiffraction
Related Subjects
43 PARTICLE ACCELERATORS
CHARGED PARTICLES
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON PROBES
ELECTRONS
FLUORESCENCE
FOCUSING
NONDESTRUCTIVE ANALYSIS
OPTICS
PHYSICS
PROBES
STRAINS
SYNCHROTRONS
TEXTURE
TRACE AMOUNTS
X-RAY DIFFRACTION
X-RAY FLUORESCENCE ANALYSIS
X-RAY SOURCES