Title: The Science and Technology of Undulators and
Wigglers
Author:
James A Clarke
Publisher: Oxford Series on Synchrotron Radiation, 4;
Oxford Science Publications 2004
Price: Price: £85.00 (hardback)
ISBN 0-19-850-8557
Synchrotron radiation is produced when an electron beam in a storage ring is deflected, and hence accelerated, by some type of magnetic insertion device, such as an undulator or a wiggler. This two hundred and thirty page text, number 4 in the Oxford Series on Synchrotron Radiation, starts at a level appropriate to a complete novice, explaining the history and outlining the physics behind such insertion devices in a clear manner. However it swiftly shifts up a gear mathematically, considering the form of synchrotron radiation from a bending magnet (Chapter 2), multipole wiggler (Chapter 3) and undulator (Chapter 4). These are not chapters for the faint hearted, but the explanations start at an appropriately simple (undergraduate) level, and can readily be followed by the more mathematically intrepid. In fact, with graphs given of all the key results, the essentials of the form of the photon flux shape, critical energy, brightness and power generated in each of these cases is readily accessible to all. This is expanded upon in Chapter 5, where a variety of numerical calculations are used to look at the flux obtainable in a range of cases.
The emphasis of the book then shifts into more practical areas. Some of the different insertion devices are introduced in Chapter 6, which uses a mixture of theoretical work and discussion to investigate the types of polarised light which can be produced from each. Chapters 7 to 9 look at the actual construction and installation of these devices. Firstly the advantages and engineering difficulties of using permanent magnets (Chapter 7) or electro-magnets (Chapter 8) are discussed, with many references to undulators and wigglers in use at various synchrotron sources. Chapter 9 considers the different methods for measuring the magnetic fields from both insertion devices and their component blocks, and, building on an earlier section on end design, shows how such results can be used to minimise any disruption to the electron beam and to provide the best possible flux. The effects of insertion devices on the electron beam are considered in more detail in Chapter 10. The fact that this chapter assumes a certain level of knowledge makes it less suitable for the interested novice, although again figures are used to illustrate all of the major points.
Chapter 11 briefly covers the role of undulators in free electron lasers. The book concludes by looking at less standard insertion devices that have been tried, together with some ideas for future devices.
The text has a reasonably useful index, and a helpful number of references. The author has tried, and largely succeeded, to avoid using jargon or terms without defining them. However the nature of the material means that there is not a single natural route through the text, and a glossary might have been useful to enable the more casual reader to dip into the book.
This fact-packed book covers the wide breadth of science underpinning the design and installation of undulators and wigglers in synchrotron radiation sources, and provides an invaluable source for those working in this field. Its direct value for the average crystallographer is less clear, as it concentrates on the devices themselves, rather than why their particular properties are useful in the design and execution of instruments and experiments.
Title: X-Ray and Electron Diffraction studies in Materials
Science
Author: D.J.Dyson
Publisher: Maney 2004
Price: £78 (hardback)
ISBN 0-19-0265 3472 368 pages
It is good to see a new book on x-ray and electron diffraction aimed at the less experienced analyst working in a materials laboratory that will also find use as an undergraduate learning aid. Supplying the units in formulae throughout the text is welcomed and will assist more detailed calculations. The author draws on his 40 years experience in the steel industry to add a wealth of real examples to illustrate the subject. The text covers a wide range of topics including useful sections on texture and electron diffraction which add to a balanced overview of the subject and its everyday application to Phase ID, quantitative and size strain analysis. The book is well supported with photographs and clear diagrams which complement the text as do comprehensive references.
The first half of the book has sections on; real space, crystal chemistry, intensity of diffraction, stereographic projection, instrument consideration and line profiles which provide a good grounding in the basics of crystallography and the theory of diffraction. The first chapter (p1 - 44) on Real Space gives a very clear introduction, through; symmetry, lattices, space groups to Bragg's law, of the basic crystallographic concepts needed for a full understanding of diffraction.
The first half of the book has sections on; real space, crystal chemistry, intensity of diffraction, stereographic projection, instrument consideration and line profiles which provide a good grounding in the basics of crystallography and the theory of diffraction. The first chapter (p1 - 44) on Real Space gives a very clear introduction, through; symmetry, lattices, space groups to Bragg's law, of the basic crystallographic concepts needed for a full understanding of diffraction.
The second chapter (p45 - 76) on Crystal Chemistry encompasses the packing of atoms within the crystal structure, building up from simple to complex inorganic systems and covering interstitial phases, metallic glasses and silicates. The next chapter on Intensity of Diffraction (p77-98) covers the factors which influence the intensity of a reflection and the equations needed to calculate its intensity, focussing particularly on the cubic system. The fourth chapter provides a useful explanation of Stereographic Projection (p99 -114) underpinning its use in later chapters. The next chapter on Instrument Considerations (p115 - 135) covers just the basics for x-ray diffraction and offers simple practical information on instrument parameters. The sixth chapter is devoted to Line Profiles (p136 - 160) and explains the factors which affect the size and shape of diffraction peaks and offers useful advice on the use of peak fitting routines.
Chapter 7 sees a move into applications and covers Phase Identification (p161 - 189). It starts with peak location and associated errors, moves on to intensity and then identification. It has sections on precision, reference materials and the figures of merit used to scale database searches. The next chapter covers Quantitative Analysis (p191 - 234) and starts with validation which is becoming increasingly important as we strive for standardisation. It covers sampling and preparation, instrument considerations specific to quantitative work and the various procedural methods. Particular cases are studied including: airborne dusts, glassy phase, metals and clay minerals. This chapter is supported by 44 references, more than any other. Chapter 9 covers Crystallite Size Analysis (p235 - 248) and offers practical advice on the various methods and their application.
The next chapter covers the specialised field of Thin Layers (p249 - 271) and introduces the use of high resolution equipment and is followed by Crystallographic Texture (p273 - 317) which is well supported with useful pictures and diagrams which help put across what is often a difficult subject in a comprehensible way. A section on Electron Backscatter leads on to the final chapter on Electron Diffraction and its Relation to XRD (p319 - 354). Here theoretical aspects including the reciprocal lattice are interspersed with practical explanations and comparisons to provide a useful grounding in understanding the complementary nature of the two disciplines.
All laboratories working on the everyday applications of x-ray and electron diffraction will find this book a useful addition to their bookshelf.
Title: International Tables for Crystallography: Vol A1:
Symmetry relations between space groups
Editors:
Hans Wondratschek and Ulrich Müller
Publisher: Published for the International Union of Crystallography by Kluwer Academic publications, 2004
Price: £155 (hardback), Euro 240 $250 (institutions /
libraries, half price for personal use
ISBN 1-4020-2355-3 731 +xii pages.
This extensive supplement to Volume A of International Tables has now appeared, and is almost as long as the volume itself. As it is an extension of the tables of sub- and supergroups in Volume A, it might be assumed to be for a very small number of specialists. In fact, it should be useful for a wide variety of crystallographers. The book is divided into three parts.
Fundamental to the organisation of the tables is the distinction between t-groups and k-groups, (here invariably given their full German names with an inflexional "e" on the end). In the first, the unit cells of the two groups are the same, while in the second, the crystal classes are the same, and a maximal subgroup or minimal supergroup must be one or the other.
With the rapid rise in the number of crystal structures determined, chemical crystallographers will increasingly need to compare structures whose similarities are masked by different space groups. For example, recently I had to compare two very similar structures in P212121 and P21/n. The relationship became clear when it was seen that these are both maximal t-subgroups of Pnma. The tables proved very useful, as they neatly relate the origin shifts and alteration in vectors required.
While this book is certainly not light reading in any sense, it will prove a valuable tool to a range of crystallographers.
Title: Mathematical Techniques in Crystallography and
Materials Science
Author: Edward Prince
Publisher: Springer Verlag 3rd edition 2004
Price: £ 30.50 (paperback)
ISBN 35 402 1111 X 224 pages
Prince's book, Mathematical Techniques in Crystallography and Materials Science, is something of a 'Desert Island' book for crystallographers, and is amongst the most important texts available in computational crystallography. Springer have now released a Third Edition, though there seem to be few, if any, differences between this and the Second Edition published in 1994. However, the book is now available in paperback costing about £30, instead of over £60 for previous hardback editions.
The book starts with a revision chapter on matrix algebra; rotations of axes, Euler angles and the metric tensor are also discussed. Chapters 2 and 3 are about symmetry, covering point groups and then developing the concepts to repeated patterns and space groups. The basics of vector algebra are covered in Chapter 4.
The material in Chapters 1-4 is mostly also available in other text-books, including for example, Giacovazzo's Fundamentals of Crystallography. Prince's book is indispensable because of what is presented in the later chapters. Chapter 5 covers tensors. More exhaustive treatments of tensor methods, with all the ramifications of co- and contra-variance, are available elsewhere, particularly in Sands' Vectors and Tensors in Crystallography. However, Prince's development of the concept of the normal distribution into a discussion of anisotropic thermal motion is particularly lucid; the discussion is developed to include higher-order models of thermal motion. Rigid body motion and the TLS model is also covered, and also extended to cover higher order terms.
Chapter 6 is entitled Data Fitting, and starts with a justification for the use of least squares. The concepts of robustness and resistance and their implementation in crystallographic weighting schemes are very clearly described, though it would have been nice at this point to have included an example or two to illustrate the effect of a robust-resistant weight-modifier on a refinement, or even to have included a reference to the author's own work in this area. Indeed, this is a more general criticism of the book, which would greatly benefit from more numerical examples and literature citations. The value of numerical illustration is evident in the following section on minimisation, in which a linear least squares example is given. The same example is developed in later chapters in sections on estimation of uncertainty (Chapter 7), correlation and the projection matrix, greatly enhancing the clarity of the text.
Chapter 8, entitled Significance and Accuracy, contains a superb discussion of correlation and methods for treating correlated refinements. It also contains a section on the projection matrix, and a description of a method for finding out which reflections are most influential for determining the precision of selected parameters. Chapter 9 deals with constraints in refinement, and includes a section on the use of rigid body constraints on thermal motion. The latter reflects Princes's work in application of the TLS model during refinement. The final chapter concerns fast Fourier transforms. There are, in addition, a number of useful appendices including listings of matrices for generating sub- and superlattices, symmetry constraints on tensor components and some useful computer subroutines. It would have been useful for the last of these to have been made available electronically.
Prince has written one of the finest accounts available on crystallographic least squares, and every graduate student should own a copy. The book makes no claim to be exhaustive in other areas of mathematical methods, however, and techniques such as simulated annealing, crystallographic uses of spherical harmonics or uses of quaternions are not discussed. Since these (and numerous other) techniques have become quite common in software, there might be scope for including some of them in future editions of this excellent book.
Simon Parsons