Narrow Results

Applications of X-ray fluorescence (XRF) analysis to solid and liquid samples with a pyroelectric X-ray generator are described. The X-ray generator is driven by a 9 V dry electric battery and small dimensions. It enables compact and portable XRF spectrometer. It has disadvantages in low power and periodically changing X-ray flux. Measured solid samples are briquettes from powdery oxides of Ti, V, Cr, Mn, Fe, Co, Ni and Cu, and sulfide of Zn. Each sample is prepared to contain equal molar metal elements. Liquid samples are solutions of Fe, Cr, Zn, Pb, Bi, Cd. Kα and Kβ lines of all metals in solid samples are detected. Although background level was relatively high for liquids, all metals in the measured samples were detected within 70 seconds, except for Cd. The capability of XRF with the pyroelectric X-ray generator is discussed.

The following sections are included:

• Introduction

• X-ray Reflectivity
  • Index on Refraction
  • Reflection from Interfaces
  • The Penetration Depth

• XAFS
  • Basic Principles of EXAFS
  • Detection of XAFS for Thin Films
    • Glancing Angle Techniques
    • Fluorescence Detection
    • Electron Yield Detection

• Experimental Examples
  • Transition Metal/Aluminum Bilayers
  • Total Reflection X-ray Flourescence Spectroscopy
  • Reflectivity Study on Liquid-vapor Interfaces
  • Polarization Dependent XAFS Studies on Thin Hetero-epitaxial Metallic Films
  • In situ MOCVD Growth Studies

• Acknowledgments

• References

The following sections are included:

• Introduction

• Basic Approaches
  • Synchrotron X-ray Production
  • X-ray Cross Sections
  • Synchrotron Radiation Induced X-ray Emission (SRIXE)
  • Extended X-ray Absorption Fine Structure (EXAFS) and Extended X-ray Absorption Near Edge Structure (XANES)
  • Computed Microtomography (CMT)
  • Sample Radiation Damage Effects

• Applications
  • Biological Applications
    • Reversible Effect of Low Lead Levels on Neuronal Growth
    • Analysis of Zinc Binding Capabilities of a Protein Domain
    • Stroke and Calcium Concentrations in the Brain
    • Studies of Bone and Cartilage
  • Geological and Extraterrestrial Materials
    • Microstructure of Shock-recovered Berea Sandstone
    • Internal Structure of Two Type-I Deep Sea Spheres by X-ray Computed Microtomography
    • Hydrothermal Vents
    • Investigation of New York/New Jersey Harbor Dredged Material
  • Environmental Chemistry
    • Secondary Ion Mass Spectroscopy and Synchrotron X-ray Fluorescence in the Study of the Qualitative Variation in Metal Content with Time in Tree Rings
  • Materials Analysis
    • Thermal Spray
    • Study of Supported Catalysts
    • Investigation of Integrated Circuit Structures Using CMT and Microdiffraction

• Summary

• Acknowledgments

• References

Phase-contrast imaging (PCI) on synchrotron radiation (SR) light source has become a paradigm in X-ray biomedical imaging. In vitro and in vivo biomedical research has attracted high attention thanks to its capability of providing high diagnostic significant images in a wide range of organs or viscera, including the breast, joints, cartilage, lung, eyes, vasculature, brain and central nervous system. In this chapter, the basic principle, main phase-contrast imaging methods and their bio-medical applications are introduced. Various imaging methods are described and evaluated. The prospect and limitations of synchrotron-based medical imaging are briefly discussed as well.

A rapidly developed during the last few years micro-X-ray fluorescence spectrometry (µXRF) is a promising multi-elemental technique for non-destructive analysis. Typically it is rather hard to perform laboratory µXRF analysis because of the difficulty of producing an original small-size X-ray beam as well as its focusing. Recently developed for X-ray beam focusing polycapillary optics offers laboratory X-ray micro probes. The combination of polycapillary lens and fine-focused micro X-ray tube can provide high intensity radiation flux on a sample that is necessary in order to perform the elemental analysis. In comparison to a pinhole, an optimized "X-ray source-op tics" system can result in radiation density gain of more than 3 orders by the value. The most advanced way to get that result is to use the confocal configuration based on two X-ray lenses, one for the fluorescence excitation and the other for the detection of secondary emission from a sample studied. In case of X-ray capillary microfocusing a µXRF instrument designed in the confocal scheme allows us to obtain a 3D elemental mapping.

In this work we will show preliminary results obtained with our prototype, a portable X-ray microscope for X-ray both imaging and fluorescence analysis; it enables µXRF elemental mapping simultaneously with X-ray imaging. A prototype of compact XRF spectrometer with a spatial resolution less than 100 µm has been designed.

X-ray emission techniques play important role in the cultural heritage area. They provide information about chemical composition of an object upon bombardment of its surface with electrons, ions, or electromagnetic radiation. Their useful features include non-destructiveness, multielemental capability, and high sensitivity for inorganic components. Especially widely used is the X-ray fluorescence technique. It utilizes electromagnetic radiation generated by X-ray tubes or radioisotope sources. X-ray fluorescence equipment is relatively simple as compared to the charged particle-based spectrometers which are combined with scanning electron microscope or ion beam accelerator. X-ray fluorescence technique can be easily adapted for in situ measurements. A portable X-ray fluorescence spectrometer has been constructed utilizing commercially available, ready made components. The construction details of the spectrometer and examples of its application are given. The key features of the portable system are the use of polycapillary X-ray optics and a vacuum chamber attachment to enhance detection of low atomic number elements such as Mg, Al, Si, P, S, and Cl. The spectrometer was applied for chemical composition analysis of archaeological artifacts and works of arts from the collections of the Museum of Fine Arts (Kunsthistorisches Museum), Vienna, Austria. The investigated objects included ancient bronzes, coins, samples of pigments, and famous goldsmith work "Saliera" by Benvenuto Cellini (1500-1571). This work highlights also other projects related to the applications of nuclear analytical techniques in support of study and preservation of cultural heritage objects supported by the International Atomic Energy Agency and carried out in the Agency's Member States.