Introduction to modern microscopy

Introduction to modern microscopy

Micron, 1976, Vol. 7: 75. Pergam~n Press. Printed in Great Britain. Book R e v i e w s I n t r o d u c t i o n to M o d e r n M i c r o s c o p y . H...

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Micron, 1976, Vol. 7: 75. Pergam~n Press. Printed in Great Britain.

Book R e v i e w s I n t r o d u c t i o n to M o d e r n M i c r o s c o p y . H. N. S O U T H W O R T H , Wykeham Science Series, Wykeham Publications Ltd., London and Winchester, pp. xiii + 218, August 1975. Price: £3.00. It is always a pleasure to be able to recommend a book because it sets out to do something worthwhile and does it well. Such is the case with this book. The author's intention--and achievement--is accurately represented by the title. In a little over two hundred pages he presents in a very readable form the necessary theory required for understanding optical systems at first year undergraduate level together with a discussion of all the major methods of microscopical examination. These include not only true optical systems such as the light and electron microscopes but also X-ray techniques, field ion and field emission microscopy and related methods of chemical and microstructural analysis. The text explains clearly the advantages and limitations of the techniques discussed but does not attempt to extend the discussion of the theory involved beyond a simple introduction. This is desirable in a first year undergraduate text: however, a well chosen list of reference texts at the end of the book will enable the reader to readily pursue any topic to a more advanced level. The examples used in the text are taken predominantly from the field of Materials Science but a number of suitable examples are included from the Biological Sciences and the text would be of equal benefit to students in either the Biological or Materials Sciences. For a modest outlay of £3 students can, with this book, provide themselves with an excellent first year text which will be of continuing use throughout their entire undergraduate course. HARVEY S, FLOWER

Practical Scanning Electron M i c r o s c o p y , Elect r o n and Ion M i c r o p r o b e Analysis. J. I. GOLDSTEIN and H. Y A K O W I T Z (editors), Plenum Press, New York and London, pp. 582 -+ xviii, 1975. Price: $42.00. The function of this book is to provide a straightforward and comprehensive introduction to scanning electron microscopy, electron and ion-microprobe analysis. The six authors, all from the United States, have adopted the tutorial style of presentation, drawing upon the valuable experience they ac-

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quired when giving undergraduate and summer school courses. Although scanning electron microscopes and electron probe microanalysers developed as separate instruments, the recent trend has been to design dual-purpose instruments. The coherent presentation of the information in the book shows that the authors have fully recognised this trend. The first chapter, on electron optics, gives the reader a clear understanding of the functioning of the electron-probe forming column, so that for any normal specimen he should be able to strike an optimum balance between the conflicting requirements of small spot size, high beam current and good depth of focus. This chapter also contains a good survey of recent developments in electron source design such as the use of field emission and lanthanum hexaboride cathodes. In the following chapters the electron beam-specimen interaction is discussed, with good explanations of electron channelling, magnetic contrast and voltage contrast. A chapter on displays includes sections on the origins and statistics of picture noise~ on the use of)/-correction and on the advantages of coloured displays, the latter topic being well illustrated with colour plates. The chapters on X-ray analysis include a clear discussion of the factors affecting sensitivity, spatial resolution and the depth of X-ray production. The use of computer programs in quantitative analysis is described in some detail and the relative merits of wavelength and energy dispersive X-ray analysis are well illustrated by comparing the spectra obtained with the two systems from a variety of specimens. The special problems encountered in analysing light elements and in dealing with delicate biological specimens are considered, including the use of critical point drying and low temperature plasma ashing in specimen preparation. The final chapter is an introduction to ion microprobe analysis, and is especially useful for its description of the application of this technique to indepth compositional profiling. In conclusion, this book can be thoroughly recommended. There is a good balance between theory and practice, the diagrams and micrographs are clear, there are hundreds of references and a good index. Although not cheap, the cost is less than the typical hire charge for an hour's use of an electron microprobe instrument. P. R. STUART