Review published in
The Geochemical News, number 113, October 2002, p.13
Synchrotron Radiation: Earth, Environmental and Material Sciences Applications. Grant S. Henderson and Don R. Baker, eds. Short Course Series 30, Mineralogical Association of Canada. Price: US $40, CDN $40
The advent of increasingly more powerful synchrotron instruments is stimulating a revolution in the Earth Sciences. Relatively readily available synchrotron radiation has impacted applications such as X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), X-ray fluorescence (XRF), and X-ray photoelectron spectroscopy (XPS). The importance of synchrotron radiation to Earth Sciences is evident by the publication of two volumes on the subject in the same year - the MAC volume which appeared in May 2002 as part of a short course in Saskatoon, Saskatchewan, and a Reviews in Mineralogy and Geochemistry (RiMG) volume that will appear as part of a short course (Applications of Synchrotron Radiation in Low-Temperature Geochemistry and Environmental Science) to be given in Monterey, California in December 2002.
The MAC volume consists of seven chapters, covering a wide range of topics. The first chapter, by T.K. Sham, is an overview of the properties of synchrotron radiation and also gives a brief history of the development of synchrotron instruments. The author also describes how synchrotron radiation is produced. I found this chapter to be quite terse and additional reading would be required to fully understand the details of what is covered. Nevertheless, it is a useful starting point for those wishing to understand some of the basics. The second chapter is primarily a description of the Canadian Light Source (CLS) by G.M. Bancroft and E.L. Hallin. The CLS is not yet fully operational, and this chapter is essentially a progress report. Thus, this chapter is likely to become obsolete in the not-too-distant future. However, there is some information in this chapter that will be of long-term use. J.S. Tee provides a brief review of powder and single crystal diffraction using synchrotron radiation and D.T. Jiang does the same for X-ray absorption fine structure spectroscopy. Chapter 5, by D.R. Baker, discusses the synchrotron X-ray microprobe. There is some material in this chapter on EXAFS and XANES that is repetitious of material in the chapter by Jiang, but such repetition doesn't hurt when dealing with such relatively complex subjects. My favorite chapter in the book is that by H.W. Nesbitt on XPS. This was the most clearly written and detailed of all the chapters. The book is rounded out by a useful chapter on the application of synchrotron radiation to the study of amorphous materials by G.S. Henderson.
In general, this book provides a lot of useful information for the potential synchrotron user in the earth sciences. The book is by no means comprehensive, but does provide an important starting point with references for delving deeper into the various subjects. The volume looks to be complementary to the upcoming RiMG volume on synchrotron radiation, and many people will want to own both volumes. The paperback book is attractive with a reasonable size font, and the price is quite affordable. The only drawback to the volume is that many of the figures are of low resolution and hence fuzzy. Few of the figures are so low resolution as to inhibit understanding, but they do detract from the volume aesthetically. Nevertheless, this is a volume worth owning.
Scott A. Wood
Department of Geosciences
University of Idaho
Review published in
Synchrotron Radiation: Earth, Environmental and Materials Sciences Applications
Edited by G. S. Henderson and D. R. Baker. Volume 30 in the Short Course Series of the Mineralogical Association of Canada (www.mineralogicalassociation.ca). Pp. 178. 2002. Price: $40 (paperback). ISBN 0921294301
Synchrotron radiation (SR) is generated when the trajectory of accelerated electrons, with a speed close to that of the speed of light, is bent by means of powerful magnets. The radiation is very intense and covers the full electromagnetic range, i.e. from the far infra-red to the hard X-ray region. Starting to become accepted as a scientific tool in the 1970, currently the research that employs SR is growing exponentially, with over 55 SR sources being planned, built or operational in 22 countries all over the world.
The material presented in this volume attempts to introduce to the general earth science community some of the basics of synchotron radiation-based research. Although the most important literature on the various areas discussed is included, it is not intended as a comprehensive review of all aspects of the techniques mentioned. Instead, it covers the basics of SR research at a level suitable for those interested in starting to perform SR experiments as part of their own research.
Chapter 1 and 2 cover the physics of synchrotron radiation and storage rings in general; the newly built Canadian Light Source (CLS), Saskatoon, Saskatchewan, Canada, is described as a concrete example. In Chapter 3, diffraction experiments conducted with SR are discussed, including both powder and singly crystal studies. X-ray absorption spectroscopy (EXAFS - Extended X-ray absorption fine structure, and XANES - X-ray absorption near-edge spectroscopy) is introduced to the novice user in Chapter 4, including a description of data reduction procedures. In Chapter 5, the experimental capabilities of the X-ray microprobe are outlined by using geological materials as examples. Such a facility allows a combination of micro-XRF (X-ray fluorescence), micro-XAS and imaging measurements to be performed. The use of synchrotron-based photoelectron spectroscopy (XPS) in the context of mineralogical and geochemical studies is discussed in Chapter 6. Finally, Chapter 7 discussed synchrotron experiments on amorphous materials.
The chapter authors and editors of this volume are all affiliated to Canadian research institutes and universities. In my opinion, they are to be complimented as they have succeeded in finding exactly the right level to introduce a rapidly expanding series of related analytical techniques to the analytical community. In most chapters, the theoretical basics of the methods are concisely described, allowing for a general understanding of the underlying principles but without excessive physical detail. Similarly, the salient features of the instrumental components are succinctly mentioned and the specific adaptations necessary for their use at a synchrotron explained. Whereas many recent papers describing geological, environmental and material science applications of the techniques can be found in the reference lists, the results actually discussed in detail were carefully selected so as to provide the reader with the maximum insight into the concrete possibilities of the techniques in the various above-mentioned fields. This volume can therefore be regarded as a very useful introductory document for natural scientists that are comtemplating to start employing SR in their own research in these fields.
Department of Chemistry
University of Antwerp, Belgium
Review published in
Chemical Geology (2003) 194,349-350
Synchrotron radiation: earth, environmental and material sciences applications
Grant S. Henderson and Don R. Baker, Editors (Short Course Series, Vol. 30, Robert Raeside, Series Editor), Mineralogical Association of Canada, Ontario, Canada, 2002, 178 pp., ISBN 0-921294-30-1 ($40)
This book is the latest in a series of volumes from by the Mineralogical Association of Canada presenting a range of science- and technique-based reviews in various areas of mineralogy. The present volume describes applications of synchrotron radiation (SR) to probe systems of relevance to the earth, environmental, and material sciences.
Synchrotron radiation is the light produced by energetic charged particles, typically electrons, as they are accelerated within a storage ring, as was first observed in the 1940s. When the energy of the electron beam is highly relativistic (i.e., its energy is substantially larger than its rest mass energy, m0c2), SR has a number of special properties that distinguish it from other sources of light. These characteristics are (1) brightness (an optical parameter that describes the ability to focus SR beams), (2) tunability (the ability to choose an arbitrary photon energy, e.g., from the infrared to hard X-rays), (3) polarization (SR is typically linearly polarized; circularly polarized SR sources are also available), (4) time structure (SR emerges in nano-to picosecond pulses), and (5) coherence (the degree to which SR exhibits "laser-like" properties). Synchrotron sources and their characteristics have evolved rapidly over the past half-century. For example, brightness for available synchrotron sources is now more than a billion times greater than that for traditional laboratory X-ray sources in the hard X-ray regime.
Synchrotron radiation sources are well matched to many of the diverse needs of the earth and environmental science communities. There are, however, few comprehensive reviews that attempt to describe both the relevant fundamentals of synchrotron facilities and the application of SR techniques to the earth and environmental sciences. Although active SR scientists often rely on the "X-ray data booklet" produced by the Center for X-ray Optics and the Advanced Light Source at the Lawrence Berkeley National Laboratory, this compact booklet is not well suited as a general introduction. The present volume, a more elementary introduction to the characteristics of SR and its applications, is derived from a short course held at the University of Saskatoon (Canada) on May 25-26, 2002. In many ways, this volume acts as a "calling card" for the new Canadian Light Source (CLS; currently under construction, to be commissioned by early 2004); it provides summaries by Canadian-based SR scientists of the main techniques that will be employed at the CLS.
The first two chapters provide background and overview. Chapter 1 (by T.K. Sham) begins with a history of synchrotron radiation and the physical basis for synchrotron radiation facilities. Descriptions are given for synchrotron facilities, their relevant storage ring parameters, and the magnetic optics that are used to produce SR. Various characteristics of SR are described: its spectral distribution, angular distribution, polarization, time structure, photon flux, and brightness. The chapter concludes by describing the fundamental mechanisms by which X-rays interact with matter (e.g., absorption and scattering). The characteristics of the CLS are described in Chapter 2 by G.M. Bancroft and E.L. Hallin. This chapter provides an overview of the techniques anticipated for the CLS and its planned operating parameters, along with a brief description of infrared and soft-X-ray microscopy capabilities not described elsewhere in this volume.
The subsequent chapters describe the following individual SR techniques that represent the traditional SR approaches to studies of materials:
The principles of powder and single-crystal dif
fraction, described in Chapter 3 by J.S. Tse, are
accompanied by descriptions of data analysis,
detection systems, and applications (primarily in
high-pressure research and time-resolved studies).
The principles of X-ray absorption spectroscopy,
described in Chapter 4 by D.-T. Jiang, include
descriptions of the X-ray absorption fine structure
(XAFS) and X-ray absorption near edge structure
(XANES) techniques, plus relevant and detailed
descriptions of experimental procedures and data
The X-ray interactions that led to the development
of the X-ray microprobe are described in Chapter 5
by D.R. Baker. The X-ray microprobe uses X-ray
fluorescence to spatially resolve the compositional
and chemical distributions with micrometer reso
lution. The necessary beamline optics and detectors
are also described, with examples in disciplines
ranging from geochemistry and ore deposits to
materials and biomedical sciences.
A review of the principles of X-ray photoelectron
spectroscopy, given by H.W. Nesbitt in Chapter 6,
covers the excitation process, equipment and
sample preparation, data analysis, and nomencla
ture. Examples include the determination of
chemical states and redox reactions through core
level shifts and the enhancement and optimization
of surface signals.
Techniques to probe amorphous materials are
discussed in Chapter 7 by G.S. Henderson, along
with the different types of order in glasses and
other amorphous materials and the use of diffrac
tion (including the use of anomalous X-ray
diffraction techniques to obtain elemental sensi
tivity) and XANES to probe short- and medium-
Some errors in the volume are likely to cause confusion for the target audience (i.e., those new to the field). These include the statement that an "EXAFS spectrum is well understood in terms of the X-ray scattering due to the presence of atoms that are neighbors". (Instead, EXAFS is due to the scattering of photoelectron waves by neighboring atoms.) Another misstatement asserts the "monochromator reduces the brilliance of the X-ray beam hitting the sample". (Instead, monochromators are designed to maintain the source brilliance but may decrease the X-ray flux.) Another error is an incorrect representation (Figs. 1-3) of the change in the electron momentum, dp, that was used to illustrate the derivation of a synchrotron's radiated power. There also are some overstatements ("To obtain microscopic information on chemical states in earth science samples, PEEM or STXM have to be used" or "The greatest impact SR has had in X-ray crystallography is on the revital-ization of powder diffraction").
Overall, this volume provides a clear and useful introduction of the topics presented, which cover the most widely used SR techniques in the area. Substantial overlap between chapters on certain common topics has the advantage of allowing each chapter to be read individually. One limitation of the volume is that it emphasizes, by design, the most widely used techniques at the expense of other powerful techniques that are not yet routinely used, such as X-ray microtomographic imaging and the X-ray scattering and absorption techniques used specifically to probe interfacial structures. However, as an introduction to synchrotron sources, the characteristics of synchrotron radiation, and the application of the most widely used SR techniques, this inexpensive volume will be a valuable reference book
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