L. KOLLER. The physics of electron tubes. International series on physics. McGraw-Hill Book Company. New York and London 1934, p. 205, 3.00.

L. KOLLER. Physics of Electron Tubes.

The contents of this book are based on lectures by the author, a member of the research laboratory of the American firm General Electric Company, at the Massachusetts Institute of Technology in the summer of 1931. The book contains 13 chapters, namely:

I. Theory of thermionic emission.
II. Various thermionic emitters, including the thoriated one.
III. Oxide cathodes.
IV. Thermionic emission of cesium.
V. Emission of secondary electrons.
VI. Determination of temperature.
VII. Getters and absorbing gases; gases in metals.
VIII. Space charge.
IX. Discharge in gases.
X. Grid-controlled arc.
XI. Photoelectric effect.
XII. Photoconductivity.
XIII. Photogalvanic effect.

And appendices:

A. Richardson’s equation.
B. Schottky’s equation.
C. Derivation of the three-halves law for coaxial cylinders.

The book is provided with a number of tables and a small number of problems.

In his preface to this book the author indicates that its main subject is the physical processes in electron tubes, and not their circuits and applications. A similar point of view, to one degree or another, is now taken by almost all authors of basic books on electron tubes (Chaffee, Barkhausen, Meller, etc.), since the experience of recent years has shown what an enormous role in the development of electron-tube technology has been played by work in the physics of electronic and ionic processes, and how essential, therefore, for the fruitful and broad application of these tubes is a clear understanding of the physical processes occurring in them. The book under review belongs to the category in which this point of view has found its maximum expression: to the detriment of consideration of the most varied physical processes occurring in tubes of different types (ordinary electron tubes, thyratrons, photoelements with external and internal photoeffect, etc.), almost no space is allotted to the physical processes characterizing the tube as a whole; for example, only one page is devoted to the principle of grid action in a triode, and not a word is said about its characteristics and parameters, to say nothing of multi-electrode tubes. On the other hand, Chapter X considers the principle of controlling the current in a thyratron in an alternating-current circuit. Thus the reader who has read this book with interest will nevertheless be unable to obtain an idea of how the physical processes discussed in the book find their, so to speak, formulation in that instrument so important for modern physics and technology, the name of which stands in the title of the book, i.e. in the electron tube.

As for the basic physical processes, their exposition is notable for great clarity and simplicity and is given in a popular descriptive form, only rarely going into a more detailed analysis of the processes considered. It should be noted that to encompass such a broad complex of questions in only 205 pages is no easy task, and in solving it the author, along with an interesting and fresh presentation of a whole series of questions (carbide and oxide cathodes, determination of temperature, etc.), has a number of shortcomings, above all an excessively (even against the general background of the book) superficial and schematic …

the presentation of a number of questions, such as, for example, the discharge gap, the valve photoeffect, etc. In general, Kohler’s book under review may be recommended as an interesting manual, written in good popular language, for an initial acquaintance with the “range” of questions considered in it, especially as the first step toward a deeper study of these processes and their application in electron tubes.

N. D. Morgulis