Bibliography

V. F. Vlasov, Electrovacuum Devices. 2nd edition, Svyazizdat, 1949, p. 519, figs. 455, price 22 rubles 50 kopecks.

In the review of the first edition of this book (UFN 31, 153 (1947)) it was already noted what a favorable impression it made as a very good and serious textbook, and at the same time a number of wishes were expressed for its further improvement. Now, at last, before us lies the next—the second—edition of this book, which appeared six years after the first. What first of all catches the eye is the greatly increased size and format of the book; this, generally speaking, is natural, since this field of modern applied physics and electronics is developing very rapidly and is at present acquiring such great importance that one would naturally expect so considerable an “expansion” of a book devoted to this subject. Interest in this book continues to be very great, since up to the present time it remains the only Soviet textbook on this subject. On the other hand, the content of this book is extremely close to the content of the latest syllabus for the course “Electronic and Ionic Devices,” approved by the Ministry of Higher Education on July 13 of this year (compiled by Senior Lecturer Vasil’ev), so that one is involuntarily compelled to draw parallels between them, especially since in this syllabus the book under review is cited as the only textbook on the subject; therefore much of what is said below about the book under review applies to some degree also to the syllabus.

Even on a first cursory examination, one immediately notices a certain inconsistency connected with the fact that in such a course, very general in its title, the principal place in practice—i.e., approximately two thirds of the total volume—is devoted to a detailed exposition only of the physics of electron tubes; in comparison with this section, all the others, devoted to other vacuum and gas-discharge devices, are presented very briefly and sometimes even superficially. This in itself causes great surprise, since the modern radio engineer has to make extensive use not only of radio tubes, but also of various photo-, secondary-electron, and electron-beam devices, gas-discharge rectifiers and converters, and so on; therefore, if in the present course an entirely correct emphasis is placed on a serious exposition of the physical principles of modern electrovacuum devices, then this should naturally apply to all the basic types of these devices without exception. Let us proceed, however, to a more detailed consideration of the contents of this book.

The book opens with an introductory chapter devoted to general information about electrovacuum devices and ends with a conclusion devoted—

technical problems and prospects for the development of technical electronics. Such an introduction and conclusion are useful for the reader, since they introduce him to the circle of these questions and give him a perspective for the future; to secure the latter, one should develop the rather limited list of literature given at the end of the book.

Chapters II and III, devoted to the physics of electron emission and cathodes, cannot, from the standpoint of their significance for such a course, unfortunately, be considered satisfactory either in scope or in content. Indeed, can six pages be considered sufficient for an exposition of the physics of photo- and secondary emission? It is difficult to agree that a student of a technical higher educational institution beginning the study of this course will really be able to understand the nature of modern effective thermo-, photo-, and secondary cathodes from the exposition presented here.

There is no doubt that this is indeed a very difficult task; however, in view of the circumstance that the cathode is one of the most basic elements of almost all modern electrovacuum devices, including electronic tubes, it is nevertheless absolutely necessary to give a coherent and systematic exposition of the physics of the modern cathode, and this cannot in any way be avoided.

On the other hand, serious objections are also raised by the sections devoted to gas discharge and gas-discharge devices, to which only 44 pages are allotted, of which only 13 pages deal with the physics of all types of gas discharge. This is already one and the same thing, irrespective of considerations, that a reader who has studied these sections will understand the phenomena in a gas discharge very poorly and that the principle of operation of gas-discharge devices will remain, to a considerable extent, unclear to him.

The main part of the book (Chs. V–XVII, comprising three quarters of its volume) is devoted to the physics of various kinds of electronic tubes. These questions, occupying the central place in the first edition of the book, received, in the present—second—edition, very extensive development, thereby showing that precisely this part is the main one, characterizing, as it were, the whole tone of the book. Beginning to read these sections, one immediately feels that it is here that the center of the author’s attention lies; he has considered these questions with the completeness, seriousness, and mastery of exposition exhaustive for such a textbook. Step by step, beginning with the simplest case of a two-electrode tube, the author gradually introduces us into the circle of all the basic types of modern radio tubes, ending with the latest novelties in the field of UHF and pulse radio engineering. It is precisely these sections that received the greatest development in this edition as compared with the first; this development proceeded by broadening those questions which already existed in the first edition (for example, the physics of multielectrode tubes, internal tube noise, etc.), and also by including in it a number of questions, essentially new, among which such interesting and important innovations predominate as the principles of operation and construction of electronic tubes for UHF (Ch. XII—tubes for ultrahigh frequencies, Ch. XVI—klystron, Ch. XVII—magnetron). The author rightly keeps in view the enormous significance that this field and the electronic tubes for it have acquired at the present time, as well as the specifically interesting peculiarity of the electronic processes in these tubes, which usually raises a number of perplexing questions in the beginning reader. The exposition of the material is very well illustrated by a number of examples and in some places reaches the high level of a scientific monograph. The author is not afraid to immerse the reader in certain subtleties of these questions, especially in the question of multielectrode tubes, etc. Reading attentively this main

and in the largest part of the book by volume, it is difficult to find any serious shortcomings; I therefore think that one can say with confidence that in this part of it, devoted to the exposition of physical phenomena in electron tubes, the book, in its high quality, is at present an excellent model as a textbook and deserves the widest possible dissemination.

In conclusion, one should express the hope that in the future—third—edition the exposition of all sections of this course, “Electrovacuum Devices,” which is broad in its title, will be raised to the very high level that characterizes here the part of the book devoted to the physics of electron tubes; in that case our Soviet educational literature on electronics will be enriched by a publication of truly first-rate quality.

N. D. Morgulis